Home

The New SU User`s Manual

1. 122 APPENDIX B HELP FACILILTIES Items labeled with an asterisk are C programs that may or may not have a self documentation feature Items labeled with a pound sign are shell scripts that may or may not have a self documentation feature To find information about these codes type sudoc program_name B 3 Suhelp html This is the text listing of Chris Liner s SU Help page SeismicUn x Version 33 5 April 1999 An HTML Help Browser This is a help browser for the SeismicUn x free software package developed and maintained by the Center for Wave Phenomena at the Colorado School of Mines The SU project is directed at CWP by John Stockwell The author of this help facility is Dr Christopher Liner an alumnus of CWP who is a faculty member in the Department of Geosciences at The University of Tulsa Last updated January 16 1998 o The arrangement below is by funtionality o Clicking on a program name pulls up the selfdoc for that item o Your web browser s Find capability is useful if you have a fragment in mind e g sort or nmo o While programs may logically apply to more than one catagory below each program appears only once 1 Functional Listing 1 Data Compression Migration and Dip Moveout Simulation and Model Building Utilities 2 Editing Sorting and Manipulation 3 Filtering Transforms and Attributes 4 Gain NMO Stack and Standard Processes 5 Graphics 6 Import Export 7 8 9
2. Alphabetical name list 280 items B 3 SUHELP HTML List is for scanning only it does not pull up the selfdoc of a selected item 123 For further info on an interesting item use your browser s find command then follow the link Data Compression Discrete Cosine Transform dctcomp dctuncomp Packing supacki suunpack1 supack2 suunpack2 wpcicomp2 wpcluncomp2 Wavelet Transform wpccompress wpcuncompress wptcomp wptuncomp wtcomp wtuncomp Go to top Editing Sorting and Manipulation suabshw suazimuth suquantile surange Edit tools subset sushw suchw suedit sutab sugethw suwind sukill suxedit Sort susort fcat suramp maxdiff surecip recip suaddnoise suresamp resamp Manipulate sudiff suswapbytes suflip sutaper suinterp suvcat sunull suzero suop swapbytes suop2 transp Go to top Filtering Transforms and Attributes suband supef One Dimensional filtering subfilt sushape suconv sufilter sutvband sufrac Ssuxcor 124 Two Dimensional filtering Transforms and Attributes sudipfilt sufxdecon sukik2filter entropy suamp suattributes suenv suhilb sufft suifft sugabor suharlan sulog suilog XK XA XA XX XX X Go to top Gain NMO Stack and Standard Processes Standard Procs Miscellaneous Velocity Analysis Graphics X window for SU format input data
3. exit 10 Discussion of numbered lines 1 This elaborate construction gets some information from the first trace header of the data set The program sugethw lists the values of the specified keys in the successive traces For example suplane sugethw tracl ns tracl 1 ns 64 tracl 2 ns 64 tracl 3 ns 64 82 CHAPTER 8 PROCESSING FLOWS WITH SU tracl 4 ns 64 tracl 5 ns 64 tracl 6 ns 64 Although sugethw is eager to give the values for every trace in the data set we only need it once The solution is to use the UNIX stream editor sed In fact we use it twice By default sed passes along its input to its output Our first use is merely to tell sed to quit after it puts the first line in the pipe The second pass through sed strips off the unwanted material before the integer In detail the second sed command reads replace or substitute everything up to the characters ns with nothing i e delete those characters We are proud of this trick The Bourne shell does not provide floating point arithmetic Where this is needed we use the UNIX built in be calculator program with the here document facility Here we make the commonly needed conversion of sampling interval which is given in micro seconds in the SEG Y header but as seconds in SU codes Note carefully the backquotes around the entire calculation we assign the result of this calculation to the shell variable on the left of the equal sign here dt The
4. Acknowledgements SU stands for CWP SU Seismic Un x a processing line developed at Colorado School of Mines partially based on Stanford Exploration Project SEP software lv Contents Acknowledgements 1 About SU Pel What UNS tas she cae A A A Te 12 What SU is not 25 4 40 2 baw aa be ee eb A a ees 1 3 Obtaining and Installing SU o e 2 Help facilities 2 1 SUHELP List the Executable Programs and Shell Scripts 2 2 SUNAME Lists the Name and Short Description of Every Item in SU 2 3 The Selfdoc Program Self Documentation o 2 4 SUDOC List the Full Online Documentation of any Item in SU 2 5 SUFIND Find SU Items with a Given String 2 5 1 Getting information about SU programs 0 2 6 GENDOCS An Instant LaTeX Document Containing All Selfdocs 2 wouhelp siti heck ate oA ae Pot ae Uy eh es be Ee Mg ed 28 MEMOS ae a Oi eke ok ee A eos Gee Ea By Se a oe OE 2 9 Other Help Mechanisms 0 000 pee ee Core Seismic Unix Programs 3 1 Reading and Writing Data to and from Tapes 00 3 1 1 The SEGY format and the SU data format 3 1 2 SEGYREAD Getting SEG Y dataintoSU 3 1 3 SEG abuses aoa a E a 3 1 4 SEGYWRITE Writing an SEGY Tape or Diskfile 3 1 5 SEGYHDRS make SEG Y ascii and binary headers for segywrite 3 1 6 BHEDTOPAR SETBHED Editing the bina
5. PWN Ee 0UR Pe 10 7 Call this file data ascii Then use a2b to convert the file to binary and then plot it with psgraph a2b lt data ascii ni 2 gt data bin n 5 psgraph lt data bin n 5 gt data6 eps Note that the n 5 that is echoed by a2b is the same as the input to psgraph This permits the following trick to be used a2b lt data ascii outpar junk par n1 2 gt data bin psgraph lt data bin par junk par gt data6 eps to yield the same output 4 1 6 PostScript Plotting of SU Data Just as there are X Windows codes for plotting SU data there are also codes for making PostScript plots of these data The programs for PostScript graphics are e SUPSCONTOUR PostScript CONTOUR plot of an SU data set e SUPSIMAGE PostScript IMAGE plot of an SU data set e SUPSCUBE PostScript CUBE plot of an SU data set e SUPSGRAPH PostScript GRAPH plot of an SU data set 48 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT e SUPSWIGB PostScript Bit mapped WIGele plot of an SU data set e SUPSWIGP PostScript Polygon filled WIGele plot of an SU data set e SUPSMAX PostScript of the MAX min or absolute max value on each trace of a SU data set We can use suplane data to test each of these programs as we did with the X Windows codes e suplane gt junk su supscontour lt junk su title contour gt datal eps supsimage lt junk su title image labeli sec label2 trace number gt data2 eps
6. short vpol vibratory polarity code code seismic signal lags pilot by 1 337 5 to 22 5 degrees 2 22 5 to 67 5 degrees 3 67 5 to 112 5 degrees 4 112 5 to 157 5 degrees 5 157 5 to 202 5 degrees 6 202 5 to 247 5 degrees 7 247 5 to 292 5 degrees 8 293 5 to 337 5 degrees HELP FACILILTIES B 4 SUKEYWORD LIST THE SU DATATYPE SEGY KEYWORDS short hunass 170 unassigned bhed DEFINES define gettr x fgettr stdin x define vgettr x fvgettr stdin x define puttr x fputtr stdout x define gettra x y fgettra stdin x y The following refer to the trid field in segy h CHARPACK represents byte packed seismic data from supack1 define CHARPACK 101 SHORTPACK represents 2 byte packed seismic data from supack2 define SHORTPACK 102 TREAL represents real time traces define TREAL 1 TDEAD represents dead time traces define TDEAD 2 TDUMMY represents dummy time traces define TDUMMY 3 TBREAK represents time break traces define TBREAK 4 UPHOLE represents uphole traces define UPHOLE 5 SWEEP represents sweep traces define SWEEP 6 TIMING represents timing traces define TIMING 7 WBREAK represents timing traces define WBREAK 8 TCMPLX represents complex time traces define TCMPLX 13 TAMPH represents time domain data in amplitude phase form define TAMPH 15 FPACK represents packed frequency domain
7. we can see that this program uses the values of 2 header fields key2 and key3 to compute a third key3 via the equation val key1 a b val key2 c val key3 d 40 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS For example to shift the values of the cdp header field by a constant amount say 1 suchw lt data gt outdata a 1 or to add a constant amount say 1000 to a header field say tracr suchw keyl tracr key2 tracr a 1000 lt infile gt outfile Another possible example is that of setting the gx field by summing the offset and sx shot point values using sushw and then computing the cdp field by averaging the sx and gx Here we are using the actual cpp locations as the cdp numbers instead of the conventional 1 2 3 enumeration suchw lt indata keyl gx key2 offset key3 sx b 1 c 1 suchw key1 cdp key2 gx key3 sx b 1 c 1 d 2 gt outdata It is possible to perform both operations in one call via suchw lt indata keyl gx cdp key2 offset gx key3 sx sx b 1 1 c 1 1 d 1 2 gt outdata 3 5 9 SUEDIT and SUXEDIT Edit the Header Words in SU Data Finally it may be that you wish to examine and possibly change just few headers For this purpose we have suedit and suxedit the SU editing programs are executed via suedit diskfile open for possible header modification if writable suedit lt diskfile open read only and permit the interactive viewing and editing of the h
8. short duse data use 1 production 2 test int offset distance from source point to receiver group negative if opposite to direction in which the line was shot int gelev receiver group elevation from sea level above sea level is positive int selev source elevation from sea level above sea level is positive int sdepth source depth positive int gdel datum elevation at receiver group int sdel datum elevation at source int swdep water depth at source int gwdep water depth at receiver group short scalel scale factor for previous 7 entries with value plus or minus 10 to the power 0 1 2 3 or 4 if positive multiply if negative divide short scalco scale factor for next 4 entries with value plus or minus 10 to the power 0 1 2 3 or 4 if positive multiply if negative divide int sx X source coordinate int sy Y source coordinate int gx X group coordinate int gy Y group coordinate short counit coordinate units code for previous four entries 1 length meters or feet 2 seconds of arc in this case the X values are longitude and the Y values are latitude a positive value designates 129 130 APPENDIX B the number of seconds east of Greenwich or north of the equator short wevel weathering velocity short swevel subweathering velocity short sut uphole time at sour
9. suvlength lt vdata gt stdout us Required parameters Ms de none TY n 2 Optional parameters MS ns output number of samples default 1st trace ns NULL Jo end self doc RRE a oR RR kkk kok kk Credits CWP Jack Cohen John Stockwell Trace header fields accessed ns Trace header fields modified ns prototype int fvgettr FILE fp segy tp segy tr main int argc char argv int ns samples on output traces 10 3 WRITING A NEW PROGRAM SUVLENGTH 103 Initialize initargs argc argv requestdoc 1 Get info from first trace if fvgettr stdin amp tr err can t get first trace if getparint ns amp ns ns tr ns Loop over the traces do int nt tr ns if nt lt ns pad with zeros memset void tr data nt 0 ns nt FSIZE tr ns ns puttr amp tr while fvgettr stdin amp tr return EXIT_SUCCESS include header h fvgettr get a segy trace from a file by file pointer nt can vary Returns int number of bytes read on current trace 0 after last trace Synopsis int fvgettr FILE fp segy tp Credits Cloned from su lib fgettr c int fvgettr FILE fp segy tp Remark In the actual SU the subroutine fvgettr has been extracted as a library function and we also made a convenience macro vgettr for the case of standard input But these are secondary considerations tha
10. DZDV determine depth derivative with respect to the velocity FARITH File ARITHmetic perform simple arithmetic with binary files FTNSTRIP convert a file of binary data plus record delimiters created FTNUNSTRIP convert C binary floats to Fortran style floats GRM Generalized Reciprocal refraction analysis for a single layer H2B convert 8 bit hexidecimal floats to binary KAPERTURE generate the k domain of a line scatterer for a seismic array MAKEVEL MAKE a VELocity function v x y z MKPARFILE convert ascii to par file format PRPLOT PRinter PLOT of 1 D arrays f x1 from a 2 D function f x1 x2 RAYT2D traveltime Tables calculated by 2D paraxial RAY tracing RECAST RECAST data type convert from one data type to another REGRID3 REwrite a ni3 ni2 ni1 GRID to a no3 no2 no1 3 D grid RESAMP RESAMPle the ist dimension of a 2 dimensional function f x1 x2 SMOOTH2 SMOOTH a uniformly sampled 2d array of data within a user SMOOTH3D 3D grid velocity SMOOTHing by the damped least squares SMOOTHINT2 SMOOTH non uniformly sampled INTerfaces via the damped SUBSET select a SUBSET of the samples from a 3 dimensional file SWAPBYTES SWAP the BYTES of various data types TRANSP TRANSPose an ni by n2 element matrix UNIF2 generate a 2 D UNIFormly sampled velocity profile from a layered UNISAM UNIformly SAMple a function y x specified as x y pairs UNISAM2 UNIformly SAMple a 2 D function f x1 x2 V
11. Stack and Standard Processes 5 Graphics 6 Import Export 7 Migration and Dip Moveout 8 Simulation and Model Building 9 Utilities Alphabetical name list 280 items List is for scanning only it For further info on an does not pull up the selfdoc of interesting item use your a selected item browser s find command then follow the link Data Compression Discrete Cosine Transform dctcomp dctuncomp 16 CHAPTER 2 HELP FACILITIES Packing supacki suunpack1 supack2 suunpack2 wpcicomp2 wpcluncomp2 Wavelet Transform wpccompress wpcuncompress wptcomp wptuncomp wtcomp wtuncomp Go to top To see the full listing see Appendix B or point your web browser to the http address above 2 8 Demos The SU package contains a suite of demos which are shell scripts located in the directory CWPROOT src demos The instructions for accessing the demos are located in the CWPROOT src demos README e The Making Data demos shows the basics of making synthetic data shot gathers and common offset sections using susynlv Particular attention is paid to illustrating good display labeling The Filtering Sufilter demo illustrates some real data processing to eliminate ground roll and first arrivals The demos in the Filtering subdirectories give instructions for accessing the data from the CWP ftp site e The Deconvolution demo uses simple synthetic spike traces to illustrate both dereverber ation and spiking decon us
12. e PSMOVIE PostScript MOVIE plot of a uniformly sampled function f x1 x2 x3 e PSWIGB PostScript WIGele trace plot of f x1 x2 via Bitmap e PSWIGP PSWIGP PostScript WIGele trace plot of f x1 x2 via Polygons 4 1 X WINDOWS PLOTTING PROGRAMS 47 Again you may create binary data to test these programs by stripping off the headers of some suplane data suplane sustrip gt data bin ni 64 n2 32 di 0 004000 nt 64 ntr 32 dt 0 004000 ns 64 The dimensions of the data are n1 64 samples per trace by n2 32 traces pscontour lt data bin n1 64 n2 32 title contour gt datal eps psimage lt data bin n1 64 n2 32 title image gt data2 eps pscube lt data bin n1 64 n2 32 title cube plot gt data4 eps pswigb lt data bin n1 64 n2 32 title bitmap wiggle trace gt data3 eps pswigp lt data bin n1 64 n2 32 title wiggle trace gt data4 eps psmovie lt data bin n1 64 n2 32 title movie gt datab eps The output files contain Adobe Level 2 Encapsulated PostScript You should be able to view these files with any standard X windows PostScript previewer such as ghostview Please note that the output from psmovie may not work on your system This output works under NeXTStep but is multi page Encapsulated PostScript which is not generally supported by PostScript devices To test psgraph make an ascii file containing a double column listing of pairs of data to be plotted such as the following
13. sometimes data don t have the dt field set Let s say that the data are sampled at 2 ms By using sukeyword we see that dt is in microseconds sukeyword dt skipping unsigned short ns number of samples in this trace unsigned short dt sample interval in micro seconds This means that the following command sequence will set all dt values to 2000 microseconds sushw lt data su key dt a 2000 gt data out su A more tangible example can be seen by piping suplane data into sushw suplane sushw key dt a 2000 sugethw key dt more 161 wenzel gt suplane sushw key dt a 2000 sugethw key dt more dt 2000 dt 2000 dt 2000 dt 2000 dt 2000 From the selfdoc for sushw we see that the following optional parameters are defined Optional parameters key cdp header key word s to set a 0 value s on first trace b 0 increment s within group c 0 group increment s d 0 trace number shift s j ULONG_MAX ULONG_MAX number of elements in group These extra options permit more complicated operations to be performed This is necessary because often there is a relationship between header fields and the position of the trace within the dataset The value of the header field is computed by the following formula i itr d val key at b i j c i 3 where itr is the trace number first trace has itr 0 NOT 1 3 5 SETTING EDITING AND VIEWING TRACE HEADER FIELDS 37 where
14. sufind ints8r Which yields INTSINC8 Functions to interpolate uniformly sampled data via 8 coeff sinc approximations ints8c interpolation of a uniformly sampled complex function y x via an For more information type sudoc program_name lt CR gt The name INTSINC8 is the name of the file that contains the library function ins8c You may now use sudoc to find out more information via sudoc intsinc8 94 CHAPTER 9 ANSWERS TO FREQUENTLY ASKED QUESTIONS Which yields In usr local cwp src cwp lib INTSINC8 Functions to interpolate uniformly sampled data via 8 coeff sinc approximations ints8c interpolation of a uniformly sampled complex function y x via an 8 coefficient sinc approximation ints8r Interpolation of a uniformly sampled real function y x via a table of 8 coefficient sinc approximations Function Prototypes void ints8c int nxin float dxin float fxin complex yinl complex yinl complex yinr int nxout float xout complex yout void ints8r int nxin float dxin float fxin float yin float yinl float yinr int nxout float xout float yout Input nxin number of x values at which y x is input dxin x sampling interval for input y x fxin x value of first sample input yin array nxin of input y x values yin 0 y fxin etc yinl value used to extrapolate yin values to left of yin 0 yinr value used to extrapolate yin values to right of yin nxin 1 nxout number of x values a
15. sumigtopo2d sustolt sumigprefd sumigpreffd sudmofk sudmofkcw XK XA XA XX XX XX 125 supswigb supswigp XX XK XA XA XX XX XX XX X XK XA XA XX X XK XA XX XX X psmovie NeXT only pswigb pswigp spsplot scmap su3dchart suchart supsmax xrects xepsb NeXT only xepsp NeXT only xepsp NeXT only segywrite setbhed suaddhead suascii suget suoldtonew supaste suput sustrip Z2XYZ sumigps sumigpspi sumigsplit sumigtk XA XX X sumigprepspi sumigpresp sudmotx X sudmovz 126 Datuming Inversion True amp migration Simulation and Model Building Simulation aka modeling Model Building Utilities XA XA XA XA XX XX XX XX XX A LA LX HF XX Utilities copyright cpall cpusec cputime ctrlstrip dirtree downfort farith filetype isatty lookpar maxints mkparfile newcase cwpfind gendocs sudoc sufind Utilities Help utilities XK XA XA XA XX XA A A A XA XA KF KF KF XX XX X APPENDIX B HELP FACILILTIES sudatumk2dr sudatumk2ds suinvvzco suinvzco3d Go to top gbbeam normray rayt2d sufdmod2 suimp2d suimp3d sukdsyn2d sureflpsvsh makevel regrid3 suintvel sustkvel tetramod tri2uni kaperture smooth2 smooth3d smoothint2 suplane XK XA XA XA XA XX XX XX XX XX XX XX XX XX XX XX KF KF Go to top overwrite pause precedence replace rmaxdiff sumax sumean sumedian sunormalize supickamp sushift suwe
16. suop2 has been provided Some of the opperations supported are to compute the e difference e sum e product e quotient e difference of a panel and a single trace e sum of a panel and a single trace e product of a panel and a single trace e quotient of a panel and a single trace The first 4 options assume that there are the same number of traces in each SU datafile In the last 4 it is assumed that there is only a single trace in the second file From the selfdoc of suop2 please note that there are 8 equivalent shell scripts commands which perform these operations 62 CHAPTER 5 GENERAL OPERATIONS ON SU DATA susum filei file2 suop2 filel file2 op sum sudiff filel file2 suop2 filel file2 op diff suprod filel file2 suop2 filel file2 op prod suquo filel file2 suop2 filel file2 op quo For panel op trace operations suptsum filel file2 suop2 filel file2 op ptsum suptdiff filel file2 suop2 filel file2 op ptdiff suptprod filei file2 suop2 filei file2 op ptprod suptquo fileil file2 suop2 file1 file2 op ptquo All of these call suop2 to perform the computation Try the following Make two files of SU data with suplane suplane gt junk1 su suxwigb lt junk1 su suxwigb title Data without noise amp suplane suaddnoise gt junk2 su suxwigb lt junk2 su suxwigb title Data with noise added amp suop2 junk2 su junk1 su op diff suxwigb title differe
17. 0 nmutexFSIZE for i 0 i lt ntaper i tr datali nmute taper i else nmute NINT ntxdt t dt memset void tr data nt nmute int 0O nmute FSIZE for i 0 i lt ntaper i tr data nt nmute 1 i taperli puttr amp tr 14 while gettr amp tr 15 return EXIT_SUCCESS 16 Discussion of numbered lines dl We maintain the internal versions of the codes with the UNIX utility RCS This item shows the string template for RCS The file su h includes directly or indirectly all our locally defined macros and prototypes The file segy h has the definitions for the trace header fields The starred lines delimit the self doc information include them exactly as you find them in the codes since they are used by the automatic documentation shells The style of the self doc shown is typical except that often additional usage information is shown at the bottom and of course often there are more options Look at some existing codes for ideas This is an external declaration of an SU SEG Y trace buffer It is external to avoid wasting stack space We usually describe the global variables at the time of declaration Examine codes related to yours to increase consistency of nomenclature there is no official SU naming standard 100 CHAPTER 10 HOW TO WRITE AN SU PROGRAM 6 The initargs subroutine sets SU s command line passing facility see page 75 7 Th
18. 0 104 PUT 0 154 PT 4 0 20 b 0 254 Figure A 1 Output of the suplane pipeline Many of these files are contained within untar me first xx tar Z A 3 A quick test Once you have completed the installation here is a quick test you can make to see if you have a functioning seismic system For an X windows machine the pipeline suplane suxwigb amp should produce the graphic shown in Figure A 1 If you have a PostScript printer then you should get a hard copy version with the pipeline suplane supswigb lpr If you have Display PostScript or a PostScript previewer then to get a screen display replace the lpr command in the pipeline by the command that opens a PostScript file for example suplane supswigb ghostview Another set of test pipelines are susynlv supsimage lpr susynlv supswigb ghostview 108 APPENDIX A OBTAINING AND INSTALLING SU Figure A 2 Output of the susynlv pipeline Appendix B Help Facililties B 1 Suhelp The full text of the output from suhelp CWP PROGRAMS no self documentation ctrlstrip downfort fcat isatty maxints pause t upfort PAR PROGRAMS programs with self documentation a2b grm rayt2d smoothint2 unisam2 xy2z b2a h2b recast subset vel2stiff Z2XYZ dzdv kaperture regrid3 swapbytes velconv farith makevel resamp transp velpert ftnstrip mkparfi
19. Again the options of this program are largely self explanatory Please note that the selfdoc is more informative than the help menu given by typing the question mark 42 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS Chapter 4 Viewing SU Data in X Windows and PostScript The Seismic Unix package has a small collection of graphics utilities for plotting data both in general C style float format and in SU format both in the X windows environment for screen viewing and in the PostScript form for hard copy The types of plotting that are available in SU are e contour plots e gray or colorscale image plots e wiggle trace plots e line or symbol graphs e movies e 3D cube plots PostScript only These programs have lengthy selfdocs reflecting the large number of options for selecting the appearance and labeling of the plots However functionality such as windowing data should be done via the programs subset or suwind as a preprocessing step before the data are actually sent to the plotting program These plotting programs are purposely not designed to window data as raw seismic datasets are often huge Also following the small is beautiful philosophy of Unix we have seprate but more or less equivalent codes for generating PostScript output for hardcopy plotting 4 1 X Windows Plotting Programs X windows provides a unified environment for the creation of screen graphics routines which can be quite portable pro
20. Common Offset data for a smooth SUINVZCO3D Seismic INVersion of Common Offset data with V Z velocity SUK1K2FILTER symmetric box like K domain filter defined by the SUKDMIG2D Kirchhoff Depth Migration of 2D poststack prestack data SUKDMIG3D Kirchhoff Depth Migration of 3D poststack prestack data B 2 SUNAME 115 SUKDSYN2D Kirchhoff Depth SYNthesis of 2D seismic data from a SUKFILTER radially symmetric K domain sin 2 tapered polygonal SUKFRAC apply FRACtional powers of ilk to data with phase shift SUKILL zero out traces SULOG time axis log stretch of seismic traces SUMAX get trace by trace local global maxima minima or absolute maximum SUMEAN get the mean values of data traces SUMEDIAN MEDIAN filter about a user defined polygonal curve with SUMIGFD 45 90 degree Finite difference migration for zero offset data SUMIGFFD Fourier finite difference migration for SUMIGGBZO MIGration via Gaussian Beams of Zero Offset SU data SUMIGPREFD The 2 D prestack common shot 45 90 degree SUMIGPREFFD The 2 D prestack common shot Fourier finite difference SUMIGPREPSPI The 2 D PREstack commom shot Phase Shift Plus SUMIGPRESP The 2 D prestack common shot split step Fourier SUMIGPS MIGration by Phase Shift with turning rays SUMIGPSPI Gazdag s phase shift plus interpolation migration SUMIGPSTI MIGration by Phase Shift for TI media with turning rays SUMIGSPLIT Split step depth migration for zero
21. SEGY headers from the traces e SUPASTE paste existing SEGY headers on existing data e SWAPBYTES SWAP the BYTES of various data types e SUSWAPBYTES SWAP the BYTES in SU data to convert data from big endian to little endian byte order and vice versa The purpose of this section is to discuss situations where these programs may be used 3 2 1 A2B and B2A ASCII to Binary Binary to ASCII Of all of the formats of data the most transportable and most space consuming is ASCII No matter what system you are working on it is possible to transport ASCII data to and from that system Also because text editors support ASCII it is usually possible to data entry and data editing in the simplest of text editors Such data probably come in a multicolumn format separated either by spaces or tabs To convert such a say 5 column dataset into binary floats type a2b lt data ascii nl 5 gt data binary The reverse operation is b2a lt data binary n1 5 gt data ascii 3 2 2 FTNSTRIP Importing Fortran Data to C Often because Fortran is a popular language in seismic data processing data may be obtained that was either created or processed in some way with Fortran Binary data in Fortran are separated by beginning of record and end of record delimiters Binary data created by C pro grams do not have any such delimiters To use Fortran data in a C program requires that the Fortran labels be stripped off via ftnstrip lt fortda
22. TRADIAL 46 TTRANS represents the transverse component define TTRANS 47 define ISSEISMIC id id 0 id TREAL id TDEAD id TDUMMY cwp_true ci define ISSEISMIC id id 0 id TREAL id TDEAD id TDUMMY id TVERT id THORZ1 id THORZ2 id TRADIAL id TTRANS cwp_true cwp_false FUNCTION PROTOTYPES ifdef __cplusplus if C specify external linkage to C functions extern C endif int fgettr FILE fp segy tp int fvgettr FILE fp segy tp void fputtr FILE fp segy tp int fgettra FILE fp segy tp int itr hdrpkge void gethval const segy tp int index Value valp void puthval segy tp int index Value valp void getbhval const bhed bhp int index Value valp void putbhval bhed bhp int index Value valp void gethdval const segy tp char key Value valp void puthdval segy tp char key Value valp char hdtype const char key char getkey const int index int getindex const char key void swaphval segy tp int index B 4 SUKEYWORD LIST THE SU DATATYPE SEGY KEYWORDS void swapbhval bhed bhp int index void printheader const segy tp void tabplot segy tp int itmin int itmax ifdef __cplusplus if C end external linkage specification endif endif 137 138 APPENDIX B HELP FACILILTIES Appendix C DEMOS a brief descriptions of th
23. and conditions 1 Permission to use copy and modify this software for any purpose without fee and within the guidelines set forth below is hereby granted provided that the above copyright notice the warranty disclaimer and this permission notice appear in all copies and the name of the Colorado School of Mines CSM not be used in advertising or publicity pertaining to this software without the specific written permission of CSM 2 The simple repackaging and selling of the SU package as is as a commercial software product is expressly forbidden without the prior written permission of CSM Any approved repackaging arrangement will carry the following restriction only a modest profit over reproduction costs may be realized by the reproducer il Approved Reference Format In publications please refer to SU as per the following example Cohen J K and Stockwell Jr J W 200_ CWP SU Seismic Un x Release No __ a free package for seismic research and processing Center for Wave Phenomena Colorado School of Mines Recent articles about SU in peer reviewed journals Saeki T 1999 A guide to Seismic Un x SU 2 examples of data processing part 1 Stockwell Jr J W 1999 The CWP SU Seismic Un x Package Computers and Geosciences Stockwell Jr J W 1997 Free Software in Education A case study of CWP SU Seismic U Templeton M E Gough C A 1998 Web Seismic Un x Making seismic reflection process
24. arbitrary velocity function of time and CDP 80 CHAPTER 8 PROCESSING FLOWS WITH SU sunmo lt stdin gt stdout optional parameters Optional Parameters vnmo 2000 NMO velocities corresponding to times in tnmo tnmo 0 NMO times corresponding to velocities in vnmo Related shell programs are su examples Nmostack and su examples Mig 8 3 Extending SU by shell programming Shell programming can be used to greatly extend the reach of SU without writing C code See for example CvStack FilterTest FirstBreak and Velan in su examples It is a sad fact that the UNIX shell is not a high level programming language consequently effective shell coding often involves arcane tricks In this section we ll provide some useful templates for some of the common UNIX shell programming idioms We use CvStack as an illustration The core of this shell is a double loop over velocities and cdps that produces velocity panels a concept not contained in any single SU program Remark For most of us writing a shell like CvStack from scratch is a time consuming affair To cut down the development time your authors excerpt from existing shells to make new ones even when we don t quite remember what every detail means We suggest that you do the same We won t comment on the lines already explained in our previous two shell code examples see Sections 8 2 1 and 8 2 3 but instead focus on the new features used in CvStack 4 bin sh Constant velocity sta
25. binary headers for segywrite SEGYREAD read an SEG Y tape SEGYWRITE write an SEG Y tape 114 APPENDIX B HELP FACILILTIES SETBHED SET the fields in a SEGY Binary tape HEaDer file as would be SU3DCHART plot x midpoints vs y midpoints for 3 D data SUABSHW replace header key word by its absolute value SUACOR auto correlation SUADDHEAD put headers on bare traces and set the tracl and ns fields SUADDNOISE add noise to traces SUAMP output amp phase real or imag trace from SUASCII print non zero header values and data SUATTRIBUTES trace ATTRIBUTES instantanteous amplitude phase SUAZIMUTH compute trace AZIMUTH given the sx sy gx gy header fields SUBFILT apply Butterworth bandpass filter SUCHART prepare data for x vs y plot SUCHW Change Header Word using one or two header word fields SUCOMMAND pipe traces having the same key header word to command SUCONV convolution with user supplied filter SUDATUMFD 2D zero offset Finite Difference acoustic wave equation SUDATUMK2DR Kirchhoff datuming of receivers for 2D prestack data SUDATUMK2DS Kirchhoff datuming of sources for 2D prestack data SUDIPFILT DIP or better SLOPE Filter in f k domain SUDIVCOR Divergence spreading correction SUDIVSTACK Diversity Stacking using either average power or peak SUDMOFK DMO via F K domain log stretch method for common offset gathers SUDMOFKCW converted wave DMO via F K domain log stretch method for SUDMO
26. calculation may take several lines We first set the number of decimal places with scale 4 and then do the conversion to seconds The characters END that follow the here document redirection symbol lt lt are arbitrary the shell takes its input from the text in the shell file until it comes to a line that contains the same characters again For more information about be man bc As the comment indicates this is a special use of the output redirection symbol that has the effect of destroying any pre existing file of the same name or opening a new file with that name In fact this is what gt always does as its first action it s a dangerous operator If you intend to append then as mentioned earlier use gt gt This is the outer loop over velocities Another warning about spaces the spaces around the bracket symbols are essential Caveat The bracket notation is a nice alternative to the older clunky test notation while test v le vmax Because the bracket notation is not documented on the typical sh manual page we have some qualms about using it But as far as we know all modern sh commands support it please let us know if you find one that doesn t WARNING OK now you know that there is a UNIX command called test So don t use the name test for one of your shell or C programs depending on your PATH setting you could be faced with seemingly inexplicable output This is the inner loop over cdp
27. cared for In the days before Internet and ftp SY was on a 9 track tape in the trunk of the car he drove from California to Colorado Ronen went to CSM to replace Jack Cohen who went on sabbatical Fortunately for SU Jack s sabbatical lasted only two months instead of the whole year initially planned because of the poor health of Jack s son Dan Upon Jack s return to CWP he became interested in SY This package was a sharp departure from the commercial seismic processing software that was available at the time The industry standard at the time was to use Fortran programs on VAX VMS based systems By the time Cohen and Ronen created the first version of SU in 1987 the sponsors of CWP had already begun showing interest in the package The availability of Unix based workstations combined with the influx of Unix literate geophysicists from the major academic institutions shifted the industry to using primarily Unix based systems for research and for processing increasing the interest in Unix based software including SU Until September of 1992 SU was used primarily in house at CWP Earlier versions of SU had been ported to CWP sponsor companies even providing the basis for in house seismic pro cessing packages developed by some of those companies Once SU became generally available 2 CHAPTER 1 ABOUT SU on the Internet it began to be used by a much broader community The package is used by exploration geophysicists earthquake seismolog
28. data define FPACK 12 FUNPACKNYQ represents complex frequency domain data define FUNPACKNYQ 11 FCMPLX represents complex frequency domain data define FCMPLX 10 FAMPH represents freq domain data in amplitude phase form define FAMPH 14 REALPART represents the real part of a trace to Nyquist define REALPART 16 IMAGPART represents the real part of a trace to Nyquist define IMAGPART 17 AMPLITUDE represents the amplitude of a trace to Nyquist define AMPLITUDE 18 PHASE represents the phase of a trace to Nyquist 135 136 APPENDIX B HELP FACILILTIES define PHASE 19 KT represents wavenumber time domain data define KT 21 KOMEGA represents wavenumber frequency domain data define KOMEGA 22 ENVELOPE represents the envelope of the complex time trace define ENVELOPE 23 INSTPHASE represents the phase of the complex time trace define INSTPHASE 24 INSTFREQ represents the frequency of the complex time trace define INSTFREQ 25 DEPTH represents traces in depth range z x define TRID_DEPTH 30 3C data v h1 h2 11 12 13 32 so a bitmask will convert between conventions TVERT represents the vertical component ttdefine TVERT 43 TVHOZ1 represents the horizontal 1 component define THORZ1 44 TVHOZ2 represents the horizontal 2 component define THORZ2 45 TRADIAL represents the radial component define
29. display of Encapsulated PostScript as a single Bitmap XEPSP X windows display of Encapsulated PostScript XIMAGE X IMAGE plot of a uniformly sampled function f x1 x2 XIMAGE X IMAGE plot of a uniformly sampled function f x1 x2 XPICKER X wiggle trace plot of f x1 x2 via Bitmap with PICKing XPSP Display conforming PostScript in an X window XWIGB X WIGgle trace plot of f x1 x2 via Bitmap In CWPROOT src Xtcwp main XGRAPH X GRAPHer XMOVIE image one or more frames of a uniformly sampled function f x1 x2 XRECTS plot rectangles on a two dimensional grid In CWPROOT src Xmcwp main FFTLAB Motif X based graphical 1D Fourier Transform In CWPROOT src su graphics psplot SUPSCONTOUR PostScript CONTOUR plot of a segy data set SUPSCUBE PostScript CUBE plot of a segy data set SUPSGRAPH PostScript GRAPH plot of a segy data set SUPSIMAGE PostScript IMAGE plot of a segy data set SUPSMAX PostScript of the MAX min or absolute max value on each trace SUPSMOVIE PostScript MOVIE plot of a segy data set SUPSWIGB PostScript Bit mapped WIGgle plot of a segy data set SUPSWIGP PostScript Polygon filled WIGgle plot of a segy data set In CWPROOT src su main BHEDTOPAR convert a Binary tape HEaDer file to PAR file format DT1TOSU Convert ground penetrating radar data in the Sensors amp Software SEGDREAD read an SEG D tape SEGYCLEAN zero out unassigned portion of header SEGYHDRS make SEG Y ascii and
30. fix is the same as for the previous question Question 3 Why do I get missing subroutine messages about ANSI C routines Isn t the GCC compiler supposed to be an ANSI compiler Answer 3 The GCC compiler is just that a compiler It draws on the libraries that are present on the machine If the GNU libraries this is the glibc package have not been installed then the GCC compiler will use the libraries that are native to the machine you are running on Because the four routines listed above are not available in the SUN 4 OS GCC does not recognize them However installing the GNU libraries will make the GCC compiler behave as a full ANSI C compiler 85 86 CHAPTER 9 ANSWERS TO FREQUENTLY ASKED QUESTIONS Question 4 Why do I get missing subroutine messages about ANSI C routines I can t get the code to compile because my compiler can t find bzero or bcopy how can I fix this Answer 4 You really shouldn t be having this problem because we try to keep to the ANSI standard but sometimes old style function calls creep in The problem of rooting these things out is exacerbated because many systems still support the old style calls If you have trouble installing because your compiler can t find bcopy or bzero make the following replacements Replace all statements of the form bzero a b with statements of the form memset void a int 0 b Please replace all instances of stateme
31. info from self docs about SU programs Usage sufind v n P lt command_pattern gt string string can be an egrep pattern sufind string gives brief synopses sufind v string verbose hunt for relevant items sufind n name_fragment searches for command name sufind P lt pattern gt string gives brief synopses by searching for string among commands libraries whose names match the pattern showing that there is some sophisticated functionality which may help you find items of a particular type in the SU package As an example of this let s say that you are looking for programs that use the fast Fourier transform algorithms in SU type 12 CHAPTER 2 HELP FACILITIES sufind fft FFTLAB Motif X based graphical 1D Fourier Transform Usage fftlab HANKEL Functions to compute discrete Hankel transforms hankelalloc allocate and return a pointer to a Hankel transformer hankelfree free a Hankel transformer PFAFFT Functions to perform Prime Factor PFA FFT s in place np a return valid n for complex to complex PFA npfar return valid n for real to complex complex to real PFA SUAMP output amp phase real or imag trace from frequency x domain data suamp lt stdin gt stdout mode amp SUFFT fft real time traces to complex frequency traces suftt lt stdin gt sdout sign 1 SUFRAC take general fractional time derivative or integral of data plus a phase shift Input is TIME DOMAIN data sufrac
32. lt data su Data often comes with some fields already set To dump these fields in a format that is convenient for geometry setting you would use sugethw in the following way sugethw lt data su output geom key keyl key2 gt hfile ascii The strings key1 key2 are the keywords representing the desired SEGY trace header fields These keywords may be listed via sukeyword o Once you have dumped the desired header fields into hfile ascii then you may edit them with the editor of your choice The point is that you may create a multi column ascii file that lists the values of specific header fields trace by trace as they appear in data su by any method you wish Each column will contain the value of a specific header field to be set Now that you have created the ascii file containing your header values you may load these values into data su via a2b lt hfile ascii ni N_columns gt hfile bin Here N_columns is the number of columns in hfile ascii This is to convert hfile ascii to a binary file Now use sushw lt data su key keyl key2 infile hfile bin gt datal su Here keyl key2 are the appropriate keywords representing the fields being set listed in the exact order the values appear column by column in hfile ascii If you want to compute a third header field from two given header field values then you may use suchw for this Also if the header fields that you want to set are systemat
33. ms short styp sweep type code 1 linear 2 cos squared 3 other short stas sweep trace length at start in ms short stae sweep trace length at end in ms short tatyp taper type l linear 2 cos 2 3 other short afilf alias filter frequency if used short afils alias filter slope short nofilf notch filter frequency if used short nofils notch filter slope short lcf low cut frequency if used short hcf high cut frequncy if used short lcs low cut slope short hcs high cut slope short year year data recorded short day day of year short hour hour of day 24 hour clock short minute minute of hour short sec second of minute short timbas time basis code 1 local 2 GMT 3 other 131 132 APPENDIX B short trwf trace weighting factor defined as 1 2 N volts for the least sigificant bit short grnors geophone group number of roll switch position one short grnofr geophone group number of trace one within original field record short grnlof geophone group number of last trace within original field record short gaps gap size total number of groups dropped short otrav overtravel taper code 1 down or behind 2 up or ahead local assignments float d1 sample spacing for non seismic data float f1 first sample location for
34. of K domain and F K domain filtering operations 5 4 6 SURESAMP Resample Data in Time Often data need to be resampled to either reduce or increase the number of samples for processing or data storage For seismic data the smart way of doing this is by the method of sinc interpolation The program suresamp e SURESAMP Resample in time performs this operation See the demos in CWPROOT src demos Filtering for further information about filtering in SU Chapter 6 Seismic Modeling Utilities An important aspect of seismic exploration and research are programs for creating synthetic data Such programs find their use both in the practical problem of modeling real data as well as in the testing of new processing programs A processing program that will not work on idealized model data will likely not work on real seismic data Another important aspect of modeling programs is the fact that many seismic processing algorithms such as migration may be viewed as inverse processes The first step in such an inverse problem may be to create a method to solve the forward problem and then formulate the solution to the inverse problem as a backpropagation of the recorded data to its position in the subsurface There are two parts to the seismic modeling task The first part is the construction of background wavespeed profiles which may consist of uniformly sampled arrays of floating point numbers The second part is the construction o
35. offset data SUMIGTK MIGration via T K domain method for common midpoint stacked data SUMIGTOPO2D Kirchhoff Depth Migration of 2D postack prestack data SUMIX compute weighted moving average trace MIX on a panel SUMUTE mute above or below a user defined polygonal curve with NMO NMO for an arbitrary velocity function of time and CDP SUNORMALIZE Trace balancing by rms max or median SUNULL create null all zeroes traces SUOCEXT smaller offset extrapolation via Offset Continuation SUOLDTONEW convert existing su data to xdr format SUOP do unary arithmetic operation on segys SUOP2 do a binary operation on two data sets SUPACK1 pack segy trace data into chars SUPACK2 pack segy trace data into 2 byte shorts SUPASTE paste existing SEGY headers on existing data SUPEF Wiener predictive error filtering SUPGC Programmed Gain Control apply agc like function SUPICKAMP pick amplitudes within user defined and resampled window SUPLANE create common offset data file with up to 3 planes SUPUT Connect SU program to file descriptor for output stream SUQUANTILE display some quantiles or ranks of a data set SURADON compute forward or reverse Radon transform or remove multiples SURAMP Linearly taper the start and or end of traces to zero SURANGE get max and min values for non zero header entries SURECIP sum opposing offsets in prepared data see below SUREDUCE convert traces to display in reduce
36. point numbers of the type that would be created by a C program then use suaddhead to put SU SEG Y trace headers on the data Example suaddhead lt datafile ns N_SAMP gt data su 9 2 DATA FORMAT QUESTIONS 87 Here N_SAMP is the integer number of samples per trace in the data 2 If your data are Fortran style floats then you would use suaddhead lt datafile ftn 1 ns NS gt data su See also Question 10 3 If your data are ASCII then use a2b ni N1 lt data ascii suaddhead ns NS gt data su Here N1 is the number of floats per line in the file data ascii 4 If you have some other data type then you may use recast lt data other in IN out float suaddhead ns NS gt data su where IN is the type int double char etc For further information consult the self docs of the programs suaddhead a2b and recast Question 7 I used segyread to read a SEG Y tape Everything seems to work fine but when I plot my data with suximage the window is black What did I do wrong Answer 7 When you read an SEG Y tape you need to pipe the data through segyclean to zero the optional SEG Y trace header field If the SU programs see nonzero values in certain parts of the optional field they try to display the data as nonseismic data using those values to set the plot parameters Another possibility is that there are a few data values that are so large that they are overwhelming the 256 gray scale levels in t
37. processing capability may encour age non processors to experiment with processing non software developers to experiment with software development and non researchers to engage in research SU is not confined to seismic applications It may find use both in geophysical and more general signal processing applications It certainly can be useful for teaching students about wave related signal processing and particularly Fourier transform properties This can include radar non seismic acoustics and image processing just to name a few Another thing that SU is not at least in its current version is a 3D package However it is not expressly a 2D package either as there are numerous filtering and trace manipulation tasks that are the same in 2D as in 3D It is likely however that there will be 3D applications in future releases of SU A single 3D migration code appeared first in Release 32 which will hopefully set the stage for new developments 1 3 Obtaining and Installing SU Because the coding standards of SU stress portability the package will install on any system that is running some form of the Unix operating system and has a decent version of make and an ANSI C compiler The programs GNU Make and GCC may be substituted for these respective programs on most systems New releases of SU are issued at 3 to 6 month intervals depending upon the accumulation of changes in the home version at CWP Old releases are not suppor
38. programs sort data window data and display data by making use of the values in the SU header fields making sukeyword an oft used utility e The essence of SU usage is the construction of shell programs to carry out coordinated data processing The su examples directory contains a number of such programs By the way the terms shell scripts shell programs shell files and shells are used interchangeably in the UNIX literature The faq directory contains a growing collection of answers to frequently asked questions about SU including detailed information about tape reading data format questions and seismic processing tips The text book Theory of Seismic Imaging by John A Scales Samizdat Press 1994 is available in our anonymous ftp site in both 300 and 400 dots per inch PostScript for mat pub samizdat texts imaging imaging 300dpi ps Z or imaging_400dpi ps Z The exercises in this text make extensive use of SU You should not hesitate to look at the source code itself Section 10 2 explains the key SU coding idioms Please let us know if you discover any inconsistencies between the source and our documentation of it We also welcome suggestions for improving the comments and style of our codes The main strength of the SU package is that it is a source code product No commercial package can give you the source code for obvious reasons You may direct email to john dix mines edu if you have comments questio
39. refraction static corrections Residual_Statics residual source receiver statics e Synthetic Making synthetic seismograms Finite_Difference finite difference 2D modeling Impulse impulse testpatterns Kirchhoff Kirchhoff modeling Reflectivity Reflectivity modeling Tetra Tetrahedrized models Tri Triangulated models Wkbj Upwind finite differencing of the eikonal equation CSHOT see the demos in CWPROOT src Fortran CSHOT Tau_P Tau p or slant stack filtering Suharlan Bill Harlan s slant stack noise suppression algorithm Sutaup Traditional Tau p transform Time_Freq_Analysis operations in the time frequency domain Utilities Miscellaneous and experimental utilities Sucommand Demo for program sucommand Velocity_Analysis NMO based velocity analysis demo Velocity_Profiles Make velocity profiles Makevel make velocity profiles with makevel Unif2 uniformly sampled 2D velocity profiles with unif2 Unisam2 uniformly sampled 2D velocity profiles with unisam2 Vel2stiff convert velocity profiles to stiffness profiles vel2stiff e Vibroseis_Sweeps Synthetic vibroseis sweeps with suvibro The beginner is encouraged to run the demos in the following order The Making Data demo shows the basics of making synthetic data shot gathers and common offset sections using susynlv Particular attention is paid to illustrating good display labeling The Filtering Sufilter demo i
40. system of equations Vx b WAVEFORMS Subroutines to define some wavelets for modeling of seimic XCOR Compute z x cross correlated with y XINDEX determine index of x with respect to an array of x values YCLIP Clip a function y x defined by linear interpolation of the YXTOXY Compute a regularly sampled monotonically increasing function x y ZASC routine to translate ncharacters from ebcdic to ascii ZEBC routine to translate ncharacters from ascii to ebcdic In CWPROOT src par lib VND VNDop int mode long lwmax int ndim long N long npanels ATOPKGE convert ascii to arithmetic and with error checking DOCPKGE Function to implement the CWP self documentation facility EALLOC Allocate and free multi dimensional arrays with error reports ERRPKGE routines for reporting errors FILESTAT Functions to determine and output the type of a file from file GETPARS Functions to GET PARameterS from the command line Numeric MODELING Seismic Modeling Subroutines for SUSYNLV and clones SMOOTH Functions to compute smoothing of 1 D or 2 D input data SUBCALLS routines for system functions with error checking SYSCALLS routines for SYSTEM CALLs with error checking 120 APPENDIX B HELP FACILILTIES In CWPROOT src su lib FGETTR Routines to get an SU trace from a file FPUTTR Routines to put an SU trace to a file HDRPKGE routines to access the SEGY header via the hdr structure TABPLOT TABPLOT selected sample points
41. the current working directory As an example make some test data with suplane and then run segyhdrs on it suplane gt data su segyhdrs lt data su You will see the files binary and header appear in your current working directory The program has options that will allow you to set the values of binary header fields These fields may be seen by typing 24 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS sukeyword jobid int jobid job identification number int lino line number only one line per reel int reno reel number short ntrpr number of data traces per record short nart number of auxiliary traces per record unsigned short hdt sample interval in micro secs for this reel unsigned short dto same for original field recording where jobid is the first binary header field The file header is an ASCII file which may be edited with a normal text editor You can put anything in there as long as the format is 40 lines of 80 characters each Segywrite will automatically convert this program The default header file created by segyhdrs looks like this C This tape was made at the C C Center for Wave Phenomena C Colorado School of Mines C Golden C0 80401 C C C 3 1 6 BHEDTOPAR SETBHED Editing the binary header file The binary header file must be converted to an ASCII form to be edited The program bhedtopar permits the binary file to be written in the form of
42. these tasks Some of the tasks for single files supported by farith include e scaling value e polarity reversal e signum function e absolute value e exponential e logarithm e square root e square e inverse punctuated e inverse of square punctuated e inverse of square root punctuated Binary operations operations involving two files include value by value e addition e subtraction e multiplication 30 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS e division e cartesian product Seismic operations which assume files consist of wavespeeds include e slowness perturbation difference of inverses of files e sloth perturbation difference of inverses of files Examples of using farith are farith in data binary op pinv out data out bin farith in datal binary in2 data2 binary op add gt data out2 bin 3 3 Trace Header Manipulation The data format of SU inherits the seismic trace headers from SEGY data If your data are not SEGY but are created by conversion from some other type there is a minimum collection of headers that you will need to set for the data to be compatible with commonly used SU programs The issues of interest in this section are e adding trace headers e removing trace headers e pasting trace headers back on 3 3 1 SUADDHEAD Adding SU Headers to Binary Data Once data have been put in the correct form that is to say an array of C style floats organized with the fas
43. trace headers changes The cdp field of the input trace headers must be the cdp bin NUMBER NOT the cdp location expressed in units of meters or feet The number of offsets to mix noffmix should typically equal the ratio of the shotpoint spacing to the cdp spacing This choice ensures that every cdp will be represented in each offset mix Traces in each mix will contribute through DMO to other traces in adjacent cdps within that mix The tdmo and vdmo arrays specify a velocity function of time that is used to implement a first order correction for depth variable velocity The times in tdmo must be monotonically increasing For each offset the minimum time at which a non zero sample exists is used to determine a mute time Output samples for times earlier than this mute time will be zeroed Computation time may be significantly reduced if the input traces are zeroed muted for early times at large offsets Trace header fields accessed ns dt delrt offset cdp By using sufind in conjunction with the selfdoc feature or sudoc and choosing smart strings to search on it is possible to find a great deal of detailed information about SU s facilities 2 6 GENDOCS An Instant LaTeX Document Containing All Selfdocs The ultimate shell script for exploiting the sudoc database is gendocs Typing gendocs o will generate the 528 page document selfdocs tex which is in LaTeX format You may process this using LaTeX on your sy
44. type suhelp CWP PROGRAMS no self documentation ctrlstrip fcat maxints t downfort isatty pause upfort PAR PROGRAMS programs with self documentation a2b kaperture resamp transp vtlvz b2a makevel smooth2 unif2 wkbj farith mkparfile smoothint2 unisam ftnstrip prplot subset unisam2 h2b recast swapbytes velconv press return key to continue Please type suhelp or see Appendix B for the full text Another useful command sequence is suhelp lpr which will the output from suhelp to the local print 2 2 SUNAME Lists the Name and Short Description of Every Item in SU A more complete listing of the contents of the CWP SU package may be obtained by typing suname SSS n CWP Free Programs CWPROOT usr local cwp Mains In CWPROOT src cwp main CTRLSTRIP Strip non graphic characters DOWNFORT change Fortran programs to lower case preserving strings FCAT fast cat with 1 read per file ISATTY pass on return from isatty 2 MAXINTS Compute maximum and minimum sizes for integer types PAUSE prompt and wait for user signal to continue T time and date for non military types UPFORT change Fortran programs to upper case preserving strings XK XX XX XX XX XX X In CWPROOT src par main 2 3 THE SELFDOC PROGRAM SELF DOCUMENTATION 7 A2B convert ascii floats to binary B2A convert binary floats to ascii DZDV determine depth derivative with respect to the velocity FARITH Fi
45. use the Unix device to device copying program dd to make an image of the entire tape on disk dd if dev rmtx of filename bs 32767 conv noerror where dev rmtx is replaced with your tapedrive device and filename is some file name you choose If this works then the next step is to try using segyread as above with tape filename If dd fails then it is likely that the hardware format of your tapedrive is not compatible with your tape Of course the best way to prevent tape reading problems is to make sure that you talk to the person who is writing the tape before they write it On SGI systems in particular there are so many possible choices for the type of tape format that the person who is making the tape must have information about the platform that the tape is intended to be read on before they can make a tape that is guaranteed to be readable 3 1 3 SEG Y abuses Unfortunately there are formats which are called SEGY but which are not true to the SEG s standards for SEGY One common variation is to honor most of the SEGY convention but have the traces be in an IEEE format Such data would be read via segyread tape dev rmt0 verbose 1 endian 1 conv 0 segyclean gt data su where the conv 0 tells the program not to attempt the IBM to float conversion DOS SEGY There is also a DOS SEGY format which is similar to the previous format with the exception that the traces and headers are al
46. 000 The program suplane generates a test pattern whose header values simulate a common offset dataset The default parameters for suplane are to make 32 traces with 64 samples per trace at 4 ms 4000 microseconds by SEG convention sampling with offset 400 The output consists of three intersecting lines of spikes Please note that corrupt data may show really strange values for a large number of the header fields Detecting such a problem is one of the primary uses of surange 3 5 5 SUGETHW Get the Values of Header Words in SU Data Having header fields on data means that there are many additional pieces of information to be kept track of besides just the seismic data themselves If you read data from a SEGY format tape segyread will preserve the trace header information in the main part of the SEGY header 3 5 SETTING EDITING AND VIEWING TRACE HEADER FIELDS 35 We saw above that surange would permit us to see the min and max header values over an entire dataset However we often need to see the values of trace header fields trace by trace and in an order that we choose The program sugethw pronounced SU get header word is just such a utility For example the command sequence sugethw lt data su key keyword1 keyword2 more Will dump the values of each of the header fields specified by the keywords listed A more tangible example using suplane data input via a pipe is suplane sugethw key tracl tracr offset d
47. 4 n2 32 title image amp xwigb lt data bin n1 64 n2 32 title wiggle trace amp xmovie lt data bin n1 64 n2 32 title movie amp SS Please note that the ampersand amp is a Unix command telling the working shell to run the program in background To test xgraph make an ASCII file containing a double column listing of pairs of data to be plotted such as the following 11 21 5 33 48 10 7 Call this file data ascii Then use a2b to convert the file to binary and then plot it with xgraph a2b lt data ascii ni 2 gt data bin n 5 xgraph lt data bin n 5 Note that the n 5 that is echoed by a2b is the same as the input to xgraph When you are finished and wish to get rid of the windows you may click on the window and type the letter q for quit On some systems you may have to actually select the destroy option by clicking and dragging on the square in the upper left hand side of the window frame Please note that all of these programs have a huge number of options reflecting a fairly large collection of functionalities See the selfdoc of each of these programs by typing programname or sudoc programname 4 1 X WINDOWS PLOTTING PROGRAMS 45 4 1 2 X Windows Plotting of SU Data To plot data that are in the SU format a number of programs many of which have parallel functionality to those already discussed have been created These are e SUXCONTOUR X CONTOUR plot of Seismic UNI
48. 428 32 traces tracl 1 32 tracr 1 32 trid 11 offset 400 ns 72 dt 4000 d1 3 571428 You will notice that the setting for the trace id trid is 11 Typing sukeyword trid 11 Fourier transformed unpacked Nyquist xr f0 xi 0 xr N 2 xi N 2 shows that trid 11 how the data are arranged in the output of the fft Of course most of the time we only want to have a quick look at the amplitude spectrum of a seismic trace or a panel of seismic traces For these purposes use suspecfx suplane suspecfx suximage title F X Amplitude Spectrum amp P P 8 p P which directly displays the amplitude spectra of each trace of the input SU data 5 1 3 2D Fourier Transforms Seismic data are generally at least 2D datasets If the data really are data in time space coordinates then the output should be in frequency wavenumber the F K domain However there are applications where we consider the data to be in two spatial dimensions x1 x2 meaning that the output is in k1 k2 We have the programs e SUSPECFK F K Fourier SPECtrum of data set e SUSPECK1K2 2D K1 K2 Fourier SPECtrum of x1 x2 data set For each of these cases Examples using suplane data are easily run using 64 CHAPTER 5 GENERAL OPERATIONS ON SU DATA suplane suspecfk suximage title F K Amplitude Spectrum amp suplane suspeck1k2 suximage title K1 K2 Amplitude Spectrum amp Please note as these are display programs so the i
49. 9 4 Geometry Setting tu eo a Poe ao ee A eens 90 viii 10 9 5 Technical Questions e 9 6 General siii a he a ee o EO Ras How to Write an SU Program 10 1 Setting up the Makefile 000 10 2 A template SU program 220 4 10 3 Writing a new program suvlength Obtaining and Installing SU A 1 Obtaining files by anonymous ftp 0 A 2 Requirements for installing the package A3 Alquiciotest aaa hs a ey be dele ek ee Help Facililties Bil Suhelp su 38 8 a A a ew bo B2 Suameer a Gover Ge Geta ge ae eS Ge Ade ee owe SSeS Bi 3 sSuhelp html a fo a eee eR a Pk et er eek Fe eG B 4 SUKEYWORD list the SU datatype SEGY Keywords DEMOS a brief descriptions of the demos CONTENTS Acknowledgments The Seismic Unix project is partially funded by the Society of Exploration Geophysicists SEG and by the Center for Wave Phenomena CWP Department of Geophysical Engineering Colorado School of Mines Past support for SU has included these groups as well as the Gas Research Institute GRI Thank you SEG and CWP for your continued support The sponsors of the CWP Consortium Project have long been partners in the SU project and we are pleased to explicitly acknowledge that relationship here In addition we wish to acknowledge extra support supplied in the past by IBM Corporation and by the Center for Geoscience Computing at the Co
50. ANDING AND USING SU SHELL PROGRAMS Plot the cmp gather suwind lt data key cdp min 1 max 2 3 sugain tpow 2 gpow 5 TT suximage f2 0 d2 1 4 label1 Time sec label2 Trace number title CMP Gathers 1 to 2 perc 99 gridi solid Y 5 Discussion of numbered lines The symbol is the comment symbol anything on the remainder of the line is not executed by the UNIX shell The combination is an exception to this rule the shell uses the file name following this symbol as a path to the program that is to execute the remainder of the shell program The author apparently intends that the shell be edited if it is necessary to change the data set she made this easier to do by introducing the shell variable data and assigning to it the full pathname of the data file The assigned value of this parameter is accessed as fdata within the shell program The parameter HOME appearing as the first component of the file path name is a UNIX maintained environment variable containing the path of the user s home directory In general there is no need for the data to be located in the user s home directory but the user would need read permission on the data file for the shell program to succeed WARNING Spaces are significant to the UNIX shell it uses them to parse command lines So despite all we ve learned about making code easy to read do not put spaces next to the symbol Somewhere around 1977 one author
51. EL2STIFF Transforms VELocities densities and Thomsen parameters VELCONV VELocity CONVersion VELPERT estimate velocity parameter perturbation from covariance VTLVZ Velocity as function of Time for Linear V Z WKBJ Compute WKBJ ray theoretic parameters via finite differencing XY2Z converts X Y pairs to spike Z values on a uniform grid Z2XYZ convert binary floats representing Z values to ascii In CWPROOT src psplot main B 2 SUNAME 113 PSBBOX change BoundingBOX of existing PostScript file PSCONTOUR PostScript CONTOURing of a two dimensional function f x1 x2 PSCUBE PostScript image plot of a data CUBE PSEPSI add an EPSI formatted preview bitmap to an EPS file PSGRAPH PostScript GRAPHer PSIMAGE PostScript IMAGE plot of a uniformly sampled function f x1 x2 PSLABEL output PostScript file consisting of a single TEXT string PSMANAGER printer MANAGER for HP 4MV and HP 5Si Mx Laserjet PSMERGE MERGE PostScript files PSMOVIE PostScript MOVIE plot of a uniformly sampled function f x1 x2 x3 PSWIGB PostScript WIGgle trace plot of f x1 x2 via Bitmap PSWIGP PostScript WIGgle trace plot of f x1 x2 via Polygons In CWPROOT src xplot main LCMAP List Color Map of root window of default screen LPROP List PROPerties of root window of default screen of display SCMAP set default standard color map RGB_DEFAULT_MAP XCONTOUR X CONTOUR plot of f x1 x2 via vector plot call XESPB X windows
52. HELLS SCRIPTS lookpar rmaxdiff sudiff sufind suhelp unglitch maxdiff suagc sudoc sufind2 sukeyword recip suband suenv sugendocs suname press return key to continue Use suname to list the name and a brief description of all of the CWP codes Use sufind to find programs by keyword name fragment Use gendocs to compile a LaTeX document listing all self docs Use sukeyword to find the SEGY header field keyword definitions Type program_name lt CR gt to view its self documentation Note not all programs listed here have the self documentation feature Type sudoc program_name to list information for these programs For answers to Frequently Asked Questions see the contents of usr local cwp src faq B 2 Suname The full text of the output from 112 APPENDIX B HELP FACILILTIES suname zarse CWP Free Programs CWPROOT usr local cwp Mains In CWPROOT src cwp main CTRLSTRIP Strip non graphic characters DOWNFORT change Fortran programs to lower case preserving strings FCAT fast cat with 1 read per file ISATTY pass on return from isatty 2 MAXINTS Compute maximum and minimum sizes for integer types PAUSE prompt and wait for user signal to continue T time and date for non military types UPFORT change Fortran programs to upper case preserving strings XK XA XA XX XX XX XX Xk In CWPROOT src par main A2B convert ascii floats to binary B2A convert binary floats to ascii
53. IX tracefile via vector plot call SUXGRAPH X windows GRAPH plot of a segy data set SUXIMAGE X windows IMAGE plot of a segy data set SUXMAX X windows graph of the MAX min or absolute max value on SUXMOVIE X MOVIE plot of a segy data set SUXPICKER X windows WIGgle plot PICKER of a segy data set SUXWIGB X windows Bit mapped WIGgle plot of a segy data set B 2 SUNAME 117 In CWPROOT src tri main GBBEAM Gaussian beam synthetic seismograms for a sloth model NORMRAY dynamic ray tracing for normal incidence rays in a sloth model TRI2UNI convert a TRlangulated model to UNIformly sampled model TRIMODEL make a triangulated sloth 1 velocity 2 model TRIRAY dynamic RAY tracing for a TRlangulated sloth model TRISEIS Gaussian beam synthetic seismograms for a sloth model UNI2TRI convert UNIformly sampled model to a TRlangulated model In CWPROOT src xtri SXPLOT X Window plot a triangulated sloth function s x1 x2 In CWPROOT src tri graphics psplot SPSPLOT plot a triangulated sloth function s x z via PostScript In CWPROOT src comp dct main DCTCOMP Compression by Discrete Cosine Transform DCTUNCOMP Discrete Cosine Transform Uncompression ENTROPY compute the ENTROPY of a signal WPTCOMP Compression by Wavelet Packet Compression WPTUNCOMP Uncompress WPT compressed data WTCOMP Compression by Wavelet Transform WTUNCOMP UNCOMPression of WT compressed data In CWPROOT src comp dwpt 1d main WPC1C
54. K global slant stacks e SUHARLAN signal noise separation by the invertible linear transformation method of Harlan 1984 e SURADON compute forward or reverse Radon transform or remove multiples by using the parabolic Radon transform to estimate multiples and subtract e SUINTERP interpolate traces using automatic event picking are provided to make use of this transform You may tests using suplane data as we have with other programs to see the output from each of these codes Both suinterp and suradon have some sophis ticated options which my require some experimentation See also the demos in CWPROOT src demos Tau_P for examples 5 4 1D Filtering Operations A large part of what is called seismic processing may be thought of as being filtering There are filtering operations for 1D applications in the SU package that span simple filtering tasks to more sophisticated tasks including deconvolution and wavelet shaping operations These operations are 1D in that they are applied trace by trace Several types of filtering operations that arise in seismic processing are e zero bandpass bandreject lowpass and highpass and notch filtering e minimum or zero phase Butterworth filtering e Wiener prediction error deconvolution e Wiener wavelets shaping e convolution e crosscorrelation e autocorrelation e data resampling with sinc interpolation e fractional derivatives integrals e median filter
55. OMP2 COMPress a 2D seismic section trace by trace using WPC1UNCOMP2 UNCOMPRESS a 2D seismic section which has been In CWPROOT src comp dwpt 2d main WPCCOMPRESS COMPRESS a 2D section using Wavelet Packets WPCUNCOMPRESS UNCOMPRESS a 2D section Shells In CWPROOT src cwp shell Grep recursively call egrep in pwd ARGV give examples of dereferencing char argv COPYRIGHT insert CSM COPYRIGHT lines at top of files in working directory CPALL RCPALL for local and remote directory tree file transfer CWPFIND look for files with patterns in CWPROOT src cwp lib DIRTREE show DIRectory TREE FILETYPE list all files of given type NEWCASE Changes the case of all the filenames in a directory dir OVERWRITE copy stdin to stdout after EOF PRECEDENCE give table of C precedences from Kernighan and Ritchie REPLACE REPLACE stringi with string2 in files THIS_YEAR print the current year TIME_NOW prints time in ZULU format with no spaces TODAYS_DATE prints today s date in ZULU format with no spaces USERNAMES get list of all login names VARLIST list variables used in a Fortran program WEEKDAY prints today s WEEKDAY designation HHH H HH HH HHH HH HOH H OH 118 APPENDIX B HELP FACILILTIES ZAP kill processes by name In CWPROOT src par shell GENDOCS generate complete list of selfdocs in latex form UPDATEDOC put self docs in doc Stripped and doc Headers UPDATEDOCALL put se
56. P fold expected per CDP ensemble short tsort trace sorting code 1 as recorded no sorting CDP ensemble e UUN i single fold continuous profile horizontally stacked short vscode vertical sum code 1 no sum 2 N two sum N sum N 32 767 short hsfs sweep frequency at start short hsfe sweep frequency at end short hslen sweep length ms short hstyp sweep type code 1 linear 2 parabolic 3 exponential 4 other 134 APPENDIX B short schn trace number of sweep channel short hstas sweep trace taper length at start if tapered the taper starts at zero time and is effective for this length short hstae sweep trace taper length at end the ending taper starts at sweep length minus the taper length at end short htatyp sweep trace taper type code 1 linear 2 cos squared 3 other short hcorr correlated data traces code 1 no 2 yes short bgrcv binary gain recovered code 1 yes 2 no short rcvm amplitude recovery method code 1 none 2 spherical divergence 3 AGC 4 other short mfeet measurement system code 1 meters 2 feet short polyt impulse signal polarity code 1 increase in pressure or upward geophone case movement gives negative number on tape 2 increase in pressure or upward geophone case movement gives positive number on tape
57. PER Taper the edge traces of a data panel to zero SUTAUP forwared and inverse T X and F K global slant stacks SUTSQ time axis time squared stretch of seismic traces SUTTOZ resample from time to depth SUTVBAND time variant bandpass filter sine squared taper SUUNPACK1 unpack segy trace data from chars to floats SUUNPACK2 unpack segy trace data from shorts to floats SUVCAT append one data set to another with or without an SUVELAN compute stacking velocity semblance for cdp gathers SUVIBRO Generates a Vibroseis sweep linear linear segment SUVLENGTH Adjust variable length traces to common length SUWEIGHT weight traces by header parameter such as offset SUWIND window traces by key word SUXCOR correlation with user supplied filter SUXEDIT examine segy diskfiles and edit headers SUZERO zero out data within a time window In CWPROOT src su graphics psplot SUPSCONTOUR PostScript CONTOUR plot of a segy data set SUPSCUBE PostScript CUBE plot of a segy data set SUPSGRAPH PostScript GRAPH plot of a segy data set SUPSIMAGE PostScript IMAGE plot of a segy data set SUPSMAX PostScript of the MAX min or absolute max value on each trace SUPSMOVIE PostScript MOVIE plot of a segy data set SUPSWIGB PostScript Bit mapped WIGgle plot of a segy data set SUPSWIGP PostScript Polygon filled WIGgle plot of a segy data set In CWPROOT src su graphics xplot SUXCONTOUR X CONTOUR plot of Seismic UN
58. Phase Shift with turning rays e SUMIGPSPI Gazdag s phase shift plus interpolation migration for zero offset data which can handle the lateral velocity variation e SUMIGSPLIT Split step depth migration for zero offset data 7 4 2 SUKDMIG2D SUMIGTOPO2D SUDATUMK2DR SUDATUMK2DS 2D Kirchhoff Migration and Datuming e SUKDMIG2D Kirchhoff Depth Migration of 2D poststack prestack data e SUDATUMK2DR Kirchhoff datuming of receivers for 2D prestack data shot gathers are the input e SUDATUMK2DS Kirchhoff datuming of sources for 2D prestack data input data are receiver gathers e SUMIGTOPO2D Kirchhoff Depth Migration of 2D postack prestack data from the variable topography recording surface 7 4 3 SUMIGFD SUMIGFFD Finite Difference Migration e SUMIGFD 45 and 60 degree Finite difference migration for zero offset data e SUMIGFFD Fourier finite difference migration for zero offset data This method is a hybrid migration which combines the advantages of phase shift and finite difference migrations 7 4 4 SUMIGTK Time Wavenumber Domain Migration This algorthm was created by Dave Hale on the fly and as far as we know exists nowhere in else geophysical literature e SUMIGTK MIGration via T K domain method for common midpoint stacked data 7 4 5 SUSTOLT Stolt Migration This is the classic F K migration method of Clayton Stolt e SUSTOLT Stolt migration for stacked data or common offset gathers Cha
59. TIVZ DMO for Transeversely Isotropic V Z media for common offset SUDMOTX DMO via T X domain Kirchhoff method for common offset gathers SUDMOVZ DMO for V Z media for common offset gathers SUEA2DF SU version of an elastic anisotropic 2D finite difference SUEDIT examine segy diskfiles and edit headers SUFDMOD2 Finite Difference MODeling 2nd order for acoustic wave equation SUFFT fft real time traces to complex frequency traces SUFILTER applies a zero phase sine squared tapered filter SUFLIP flip a data set in various ways SUFRAC take general fractional time derivative or integral of SUFXDECON random noise attenuation by FX DECONvolution SUGABOR Outputs a time frequency representation of seismic data via SUGAIN apply various types of gain to display traces SUGAZMIG SU version of Jeno GAZDAG s phase shift migration SUGET Connect SU program to file descriptor for input stream SUGETHW sugethw writes the values of the selected key words SUHARLAN signal noise separation by the invertible linear SUHILB Hilbert transform SUIFFT fft complex frequency traces to real time traces SUILOG time axis inverse log stretch of seismic traces SUIMP2D generate shot records for a line scatterer SUIMP3D generate inplane shot records for a point SUINTERP interpolate traces using automatic event picking SUINTVEL convert stacking velocity model to interval velocity model SUINVXZCO Seismic INVersion of
60. The Vew SU User s Manual John W Stockwell Jr amp Jack K Cohen Version 3 2 August 2002 The Seismic Unix project is supported by these organizations The Society of Exploration Geophysicists Center for Wave Phenomena Colorado School of Mines Golden CO 80401 USA Past support was received from The Gas Research Institute ng The CWP SU Free Software Package Legal Matters This file is property of the Colorado School of Mines Copyright 2004 Colorado School of Mines all rights reserved Warranty Disclaimer NO GUARANTEES OR WARRANTIES EITHER EXPRESS OR IMPLIED ARE PROVIDED BY CWP CSM ANY EMPLOYEE OR MEMBER OF THE AFORESAID ORGANIZATIONS OR BY ANY CONTRIBUTOR TO THIS SOFTWARE PACKAGE REGARDING THE ACCURACY SAFETY FITNESS FOR A PARTICULAR PURPOSE OR ANY OTHER QUALITY OR CHARACTERISTIC OF THIS SOFTWARE OR ANY DERIVATIVE SOFTWARE Export restriction Disclaimer We believe that CWP SU Seismic Un x is a low technology product that does not appear on the Department of Commerce CCL list of restricted exports Accordingly we believe that our product meets the qualifications of an ECCN export control classification number of EAR99 and we believe it fits the qualifications of NRR no restrictions required and is thus not subject to export restrictions of any variety Limited License The CWP SU Seismic Un x package SU is not public domain software but it is available free under the following terms
61. X tracefile via vector plot call e SUXIMAGE X windows IMAGE plot of an SU data set e SUXWIGB X windows Bit mapped WIGele plot of an SU data set e SUXGRAPH X windows GRAPH plot of an SU data set e SUXMOVIE X MOVIE plot of an SU data set e SUXMAX X windows graph of the MAX min or absolute max value on each trace of an SU data set Rather than maintain multiple codes each of these programs actually calls one or more of the X windows graphics programs listed in the previous subsection Please note that the selfdoc of the non SU version of a given graphics program also applies to the SU version meaning that these programs also have a large functionality You may test each of these programs using suplane data via suxcontour title contour amp suximage title image amp suxwigb title wiggle trace amp suxgraph title graph amp suxmovie title movie amp suxmax title max amp suplane suplane suplane suplane suplane suplane Again note that the ampersand amp is a Unix command telling the working shell to run the program in background When you are finished and wish to get rid of the windows you may click on the window and type the letter q for quit On some systems you may have to actually select the destroy option by clicking and dragging on the square in the upper left hand side of the window frame 4 1 3 Special Features of X Windows Programs To fin
62. a 34 3 5 6 SUSHW Set the Header Words in SU Data 36 3 5 7 Setting Geometry Converting Observers Logs to Trace Headers 38 3 5 8 SUCHW Change or Compute Header Words in SU Data 39 3 5 9 SUEDIT and SUXEDIT Edit the Header Words in SU Data 40 4 Viewing SU Data in X Windows and PostScript 43 4 1 X Windows Plotting Programs e 43 4 1 1 Plotting General Floating Point Data 44 4 1 2 X Windows Plotting of SU Data 0 45 4 1 3 Special Features of X Windows Programs 45 4 1 4 PostScript Plotting Programs e 46 4 1 5 PostScript Plotting of General Floating Point Data 46 4 1 6 PostScript Plotting of SU Data 0 004 47 4 2 Additional PostScript Support 0 0002 eee ee 48 4 2 1 PSBBOX Changing the BoundingBox 48 4 2 2 PSMERGE MERGE2 MERGE4 Merging PostScript Plots 49 4 3 Trace Picking Utilities torera A E A ee 51 4 4 EditineSU Data s yonde agan A ia Ee eee EP E 51 4 4 1 SUWIND window traces by key word 2 52 4 4 2 SUSORT sort on any SEGY header keywords 54 4 43 SURAMP and SUTAPER tapering data values 55 4 44 SUKILL SUZERO SUNULL SUMUTE zeroing out data 55 4 45 SUVCAT and CAT Concatenating Data 56 4 46 SUVLENGTH Adjust Variable Length Traces to a Commo
63. a parfile bhedtopar lt binary outpar binary par which for the case of the header file created for the test SU data appears as follows jobid 1 lino 1 reno 1 ntrpr 0 nart 0 hdt 4000 The values that are assigned to the various header files may be edited and be reloaded into the header file via setbhed setbhed bfile binary par binary par 3 2 DATA FORMAT CONVERSION 25 Individual header field values may also be set For example setbhed bfile binary par binary par lino 3 which uses the contents of binary par but with the field lino set to 3 Finally the tape may be written via a command sequence like this segywrite tape dev rmtx verbose 1 lt data su taking care to note that the files header and binary are in the current working directory You may use different names for these files if you wish Segywrite has a bfile and an hfile option to permit you to input the files by the different names you choose 3 1 7 SEGDREAD Other SEG formats There are other SEG formats SEG A SEG B SEG X SEG C SEG D SEG 1 and SEG 2 Of these SEG D SEG B and SEG 2 are the types that you will most commonly encounter There is a segdread program which supports only 1 of the vast number of variations on SEG D In the directory CWPROOT Third_Party is a seg2segy conversion program which may be used to convert SEG 2 format to SEG Y Future plans are to create a seg2read program which will be similar
64. afile consisting of C style binary floating point numbers do suaddhead lt data bin ns 1024 gt data su or for some other type such as integers use recast recast lt data ints in int out float suaddhead ns 1024 gt data su Here we have used a pipe to cascade the processing flow If the data are integers were originally from Fortran then this is a likely processing flow ftnstrip lt data fortran recast in int out float suaddhead ns 1024 gt data su Other variations are obviously possible 3 5 2 SUSTRIP and SUPASTE Strip and Paste SU Headers sustrip lt data su head data head gt data strip Other processing that doesn t change the number of traces supaste lt datanew strip head data head gt datanew su See the discussion of sustrip and supaste above 3 5 3 SUKEYWORD See SU Keywords The next 5 programs that are discussed in this section have the option key in their selfdocs and the reference to the trace header field keywords As has been discussed in Chapter 2 sukeyword is used to determine just what these header keywords are Typing sukeyword o shows this list You may also see this list in Appendix B However of the 80 fields which are defined in the SU header only a relatively small subset are used most of the time These fields are given by the sukeyword listing as int tracl trace sequence number within line int tracr trace sequence number wi
65. ast collection of programs perform a form of crude muting of the data For a more precise muting operation there is sumute which can perform surgical muting of SU data The program may be used by specifying trace header field to mute on via the key parameter sumute lt indata su gt outdata su key KEYWORD xmute x1 x2 x3 tmute t1 t2 t3 An suplane data example of this is to compare original suplane data made by suplane suxwigb amp with surgically muted data suplane sumute key tracl xmute 1 10 12 tmute 06 1 11 suxwigb This says to mute every arrival above the polygonal curve defined by the curve defined by the xmute and tmute values The program also permits the x t values to be input from binary files by setting the options nmute xfile and tfile as listed in a portion of the selfdoc for this program nmute number of x t values defining mute xfile file containing position values as specified by the key parameter tfile file containing corresponding time values sec tracl use trace number instead ntaper 0 number of points to taper before hard mute sine squared taper below 0 1 to zero BELOW the polygonal curve Please note also that above and below refer to the appearance on a seismic plot such as the suxwigb plot and not to the time values 4 4 5 SUVCAT and CAT Concatenating Data There are two possible ways of appending one dataset onto another concatenat
66. at reads a new trace at the bottom of the loop 12 We favor using local variables where permitted 13 This is the seismic algorithm here incomplete We ve left in some of the actual sumute code because it happens to contains lines that will be useful in the new code we ll be writing below You may want to call a subroutine here to do the real work 14 fputtr and puttr are the output analogs of fgettr and gettr 15 The loop end gettr returns a 0 when the trace file is exhausted and the processing then stops 16 This is an ANSI C macro conventionally used to indicate successful program termination 10 3 Writing a new program suvlength A user asked about SU processing for variable length traces At his institute data are collected from time of excitation to a variable termination time The difficulty is that SU processing is based on the SEG Y standard which mandates that all traces in the data set be of the same length Rather than contemplating changing all of SU it seems to us that the solution is to provide a program that converts the variable length data to fixed length data by padding with zeroes where necessary at the end of the traces let s name this new program suvlength We can make the length of the output traces a user parameter If there is a reasonable choice it makes sense to provide a default value for parameters Here using the length of the first trace seems the best choice since that value can be ascertained befo
67. came up originally when a student had destroyed an original dataset by accident but only had a bit mapped PostScript image of the data Using h2b it was possible to recover the data from the PostScript file 3 2 DATA FORMAT CONVERSION 29 3 2 6 TRANSP Transposing Binary Data In the course of any of the operations it is often necessary to transpose datasets In particular data which are represented in a multi column ASCII format will likely need to be transposed after being converted from ASCII to binary with a2b The reason for this is that it is convenient to have the fast dimension of the data be the time or depth dimension for seismic purposes Our example above was a 5 column dataset which you might think of as 5 seismic traces with the same number of samples in each trace side by side in the file The processing sequence a2b lt data ascii ni 5 gt data binary will result in a file with the fast dimension being in the trace number direction rather than the number of samples direction The additional processing sequence transp lt data binary n1 5 gt data transp will put the data in the desirable form of the fast dimension being in the number of samples direction so that each trace is accessed successively 3 2 7 FARITH Performs simple arithmetic on binary data It is often necessary to perform arithmetical operations on files or between two files of binary data The program farith has been provided for many of
68. cdpmax dxcdp noffmix SUFDMOD2 Finite Difference MODeling 2nd order for acoustic wave equation sufdmod2 lt vfile gt wfile nx nz tmax xs zs optional parameters SUSTOLT Stolt migration for stacked data or common offset gathers sustolt lt stdin gt stdout cdpmin cdpmax dxcdp noffmix The last two hits are spurious but we see that three DMO programs have been found Now use the self doc facility to get more information about sudmofk sudmofk SUDMOFK DMO via F K domain log stretch method for common offset gathers sudmofk lt stdin gt stdout cdpmin cdpmax dxcdp noffmix Required Parameters cdpmin minimum cdp integer number for which to apply DMO cdpmax maximum cdp integer number for which to apply DMO dxcdp distance between adjacent cdp bins m noffmix number of offsets to mix see notes The phrase carriage return refers to an older technology the typewriter Ask your parents or grandparents for further details 14 CHAPTER 2 HELP FACILITIES Optional Parameters tdmo 0 0 times corresponding to rms velocities in vdmo s vdmo 1500 0 rms velocities corresponding to times in tdmo m s sdmo 1 0 DMO stretch factor try 0 6 for typical v z fmax 0 5 dt maximum frequency in input traces Hz verbose 0 1 for diagnostic print Notes Input traces should be sorted into common offset gathers One common offset gather ends and another begins when the offset field of the
69. ce short gut uphole time at receiver group short sstat source static correction short gstat group static correction short tstat total static applied short laga lag time A time in ms between end of 240 byte trace identification header and time break positive if time break occurs after end of header time break is defined as the initiation pulse which maybe recorded on an auxiliary trace or as otherwise specified by the recording system short lagb lag time B time in ms between the time break and the initiation time of the energy source may be positive or negative short delrt delay recording time time in ms between initiation time of energy source and time when recording of data samples begins for deep water work if recording does not start at zero time short muts mute time start short mute mute time end unsigned short ns number of samples in this trace unsigned short dt sample interval in micro seconds short gain gain type of field instruments code 1 fixed 2 binary 3 floating point 4 N optional use short igc instrument gain constant short igi instrument early or initial gain HELP FACILILTIES B 4 SUKEYWORD LIST THE SU DATATYPE SEGY KEYWORDS short corr correlated 1 no 2 yes short sfs sweep frequency at start short sfe sweep frequency at end short slen sweep length in
70. ck of a range of cmp gathers Authors Jack Ken NOTE Comment lines preceding user input start with set xX Set input output file names and data parameters input cdp601t0610 stackdata cvstack cdpmin 601 cdpmax 610 fold 30 space 1 1 null trace between panels Determine velocity sampling vmin 1500 vmax 3000 dv 150 Determine ns and dt from data for sunull nt sugethw ns lt input sed 1q sed s ns 1 dt sugethw dt lt input sed 1q sed s dt Convert dt to seconds from header value in microseconds dt bc 1 lt lt END 2 scale 4 dt 1000000 END 8 3 EXTENDING SU BY SHELL PROGRAMMING 81 Do the velocity analyses gt stackdata zero output file 3 v vmin while v le vmax 4 do cdp cdpmin while cdp le cdpmax 5 do suwind lt input 6 key cdp min cdp max cdp count fold sunmo cdp cdp vnmo v tnmo 0 0 sustack gt gt stackdata cdp bc 1 lt lt END 7 cdp 1 END done sunull ntr space nt nt dt dt gt gt stackdata 8 v bc 1 lt lt END v dv END done Plot the common velocity stacked data ncdp bc 1 lt lt END cdpmax cdpmin 1 END f2 vmin d2 bc 1 lt lt END dv ncdp space 9 END sugain lt stackdata tpow 2 0 suximage perc 99 f2 f2 d2 d2 title File input Constant Velocity Stack label1 Time s label2 Velocity m s
71. d 1 3 data 3 2 4 H2B Importing 8 Bit Hexidecimal The issue of converting 8 bit hexidecimal may seem to be one that would not come up very often However 8 bit hex is a common format for bitmapped images grayscale PostScript and if you wish to take a scanned image and turn it into floats for further processing then it will come up If you have a scanned image written as a 256 level grayscale bitmapped PostScript image then the bitmap portion is in 8 bit hex By removing all of the PostScript commands and leaving only the bitmap then the command h2b lt hexdata gt floatdata will convert the bitmap into a form that can be viewed and processed by programs in the CWP SU package 3 2 5 RECAST Changing Binary Data Types Of course C supports a variety of types and instead of having a bunch of program to convert each type into every other type there is a program called recast that will do the job for a large collection of these types Types supported by recast for input and output e float floating point e double double precision e int signed integer char character e uchar unsigned char e short short integer e long long integer e ulong unsigned long integer For example to convert integers to floats recast lt data ints in int out float gt data floats The name of this program derives from the fact that an explicit type conversion in the C language is called a cast 1This issue
72. d cross correlation may be performed with suconv and sux cor respectively The filter may be supplied as a vector input on the commandline or as a file containing a single trace in SU format In addition to taking the input as a single trace it is possible to supply a panel of filters each to be used trace by trace on a panel of SU data An example of correlating a vibroseis sweep may be seen by creating vibroseis like data with suvi bro suplane and suconv To make vibroseis suplane data suvibro gt junk vib su suplane suconv sufile junk vib su gt plane vib su Because surange tells us that surange lt junk vib su 1 traces tracl 1 ns 2500 dt 4000 sfs 10 sfe 60 slen 10000 styp 1 there are 2500 samples on the vibroseis sweep we can do the following correlation suxcor lt plane vib su sufile junk vib su suwind itmin 2500 itmax 2563 sushw key delrt a 0 0 gt data su this line is broken to make it fit on the page here the real command is typed on a single line The value of itmin sweeplength and itmax sweeplength nsout where nsout is the number of samples expected in the output The final step using sushw is to set the trace delay to 0 Choosing it min sweeplength will ensure that the data start at the correct value Choosing nsout sweeplength nsin where nsin is the number of samples in the input will yield the correct number of samples to keep 5 4 4 SUPEF Wiener predictive error filtering The
73. d is not typed as part of the command The following tools provide internal documentation at various levels of detail for the main programs shell scripts and library functions in the package e SUHELP list the CWP SU programs and shells e SUNAME get name line from self docs and location of the source code The selfdoc is an internal documentation utility which exists in the majority of executable mains and shell scripts The selfdoc is seen by typing the name of the program or shell script on the commandline with no arguments and without redirection of input or output via pipes or Unix redirects gt lt For non executables library routines and for programs without the selfdoc feature there is a dummy selfdoc included which provides a database of information about those items as well e SUDOC get DOC listing for code SUFIND get info from self docs e GENDOCS generate complete list of selfdocs in latex form e suhelp html is an HTML global overview of SU programs by subject matter e SUKEYWORD guide to SU keywords in segy h This chapter discusses each of these utilities with the intent of showing the reader how to get from the most general to the most specific information about SU programs 6 CHAPTER 2 HELP FACILITIES 2 1 SUHELP List the Executable Programs and Shell Scripts For a general listing of the contents of SU which includes each executable that is each main program and shell script in the package
74. d out all of the many options of these programs please see their selfdocs by typing the names of each of these programs on the commandline suxcontour suxwigb suximage suxmovie suxmax In addition the names of the non SU versions of some of these programs may be typed to yield additional information xcontour xwigb ximage xmovie of ox of However there are some properties that these programs have that can only be illustrated with examples 46 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT Plotting wiggle traces in true offset with SUXWIGB It is possible to plot wiggle traces in true offset that is to say to take the values for the horizontal dimension of the wiggle plot from the values in the header This is done with the key parameter For example lets make some test data with suplane and plot it using the key offset via suplane suchw keyl offset key2 tracl a 0 b 100 suxwigb key offset amp The result is a plot with the x2 axis labeled in the values of the offset header field which count by 100 s Making a movie with SUXMOVIE It is possible to make movies of seismic data with suxmovie An example of this is to make several synthetic data panels with suplane appending each successive panel with the double redirect sign suplane gt junk1 su suplane suaddnoise sn 20 gt gt junki su suplane suaddnoise sn 15 gt gt junki su suplane suaddnoise s
75. d time SURELAN compute residual moveout semblance for cdp gathers based SURESAMP Resample in time SURESSTAT Surface consistent source and receiver statics calculation SUSHAPE Wiener shaping filter SUSHIFT shifted windowed traces in time SUSHW Set one or more Header Words using trace number mod and SUSORT sort on any segy header keywords SUSPECFK F K Fourier SPECtrum of data set 116 APPENDIX B HELP FACILILTIES SUSPECFX Fourier SPECtrum T gt F of traces SUSPECK1K2 2D K1 K2 Fourier SPECtrum of x1 x2 data set SUSPIKE make a small spike data set SUSTACK stack adjacent traces having the same key header word SUSTATIC Elevation static corrections apply corrections from SUSTKVEL convert constant dip layer interval velocity model to the SUSTOLT Stolt migration for stacked data or common offset gathers SUSTRIP remove the SEGY headers from the traces SUSWAPBYTES SWAP the BYTES in SU data to convert data from big endian SUSYNCZ SYNthetic seismograms for piecewise constant V Z function SUSYNLV SYNthetic seismograms for Linear Velocity function SUSYNLVCW SYNthetic seismograms for Linear Velocity function SUSYNLVFTI SYNthetic seismograms for Linear Velocity function in a factored SUSYNVXZ SYNthetic seismograms of common offset V X Z media via SUSYNVXZCS SYNthetic seismograms of common shot in V X Z media via SUTAB print non zero header values and data for non graphic terminals SUTA
76. de uniform in number of samples e concatenated which are dataset editing issues This section therefore will deal with the following programs e SUWIND window traces by key word e SUSORT sort on any segy header keywords e SURAMP Linearly taper the start and or end of traces to zero e SUTAPER Taper the edge traces of a data panel to zero e SUNULL create null all zeroes traces e SUZERO zero out data within a time window e SUKILL zero out traces e SUMUTE mute above or below a user defined polygonal curve with the distance along the curve specified by key header word e SUVLENGTH Adjust variable length traces to common length e SUVCAT append one data set to another trace by trace which provide a variety of trace editing utilities 52 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT 4 4 1 SUWIND window traces by key word It is very common to view or process only a subset of a seismic dataset Because seismic data have a number of parameters that we may want to window the data about suwind has been written Windowing by trace header field In its simplist usage suwind permits the user to set min and max values of a specific header field key tracl Key header word to window on see segy h min LONG_MIN min value of key header word to pass max LONG_MAX max value of key header word to pass For example windowing suplane data by trace number yields suplane suwind key tracl m
77. dlimited HalF DIFFerentiator MKSINC Compute least squares optimal sinc interpolation coefficients MNEWT Solve non linear system of equations f x 0 via Newton s method PFAFFT Functions to perform Prime Factor PFA FFT s in place POLAR Functions to map data in rectangular coordinates to polar and vise versa PRINTERPLOT Functions to make a printer plot of a 1 dimensional array QUEST Functions to ESTimate Quantiles RESSINC8 Functions to resample uniformly sampled data via 8 coefficient sinc RFWIVA Rasterize a Float array as Wiggle Trace Variable Area RFWIVAINT Rasterize a Float array as Wiggle Trace Variable Area with SBLAS Single precision Basic Linear Algebra Subroutines SCAXIS compute a readable scale for use in plotting axes SGA Single precision general matrix functions adapted from LINPACK FORTRAN SHFS8R Shift a uniformly sampled real valued function y x via SINC Return SINC x for as floats or as doubles SORT Functions to sort arrays of data or arrays of indices SQR Single precision QR decomposition functions adapted from LINPACK FORTRAN STOEP Functions to solve a symmetric Toeplitz linear system of equations STRSTUFF STRing manuplation subs SWAPBYTE Functions to SWAP the BYTE order of binary data TEMPORARY_FILENAME Creates a file name in a user specified directory TRIDIAGONAL Functions to solve tridiagonal systems of equations Tu r for u VANDERMONDE Functions to solve Vandermonde
78. e demos The directiory CWPROOT src demos contains a number of subdirectories containing ready to run shell scripts to demostrate SU programs This collection is nowhere as complete as it should be and is continually changing and being updated BC_Examples Block Demo for the program block in the free package UNCERT 3D_Model_Building Tetramod Demo for tetra the seismic wavespeed model building code Datuming Examples of datuming Finite_Difference Traditional Finite difference Datuming Kirchhoff_Datuming Kirchhoff datuming x Migration_with_topography Migration with topographics effects Deconvolution Deconvolution demos Wiener_Levinson prediction error filtering FX frequency wavenumber Dip Moveout Dip Moveout Ti Dip moveout in transversely isotropic media Diversity_Stacking Filtering Filtering demos Subfilt Butterworth filter Sudipfilt Dip slope filtering Sufilter Polygonal zero phase frequency filtering Sugabor time frequency filtering via the Gabor transform Suk1k2filter Wavenumber filtering box Sukfilter Wavenumber filtering annular Sumedian Median filtering 139 140 APPENDIX C DEMOS A BRIEF DESCRIPTIONS OF THE DEMOS Making Data Making synthetic seismic profiles CommonOffset Common offset and Zero offset datasets ShotGathers Common shot datasets Migration_Inversion Migration Inversion 3D Migration or inve
79. e an file of input wavespeed The other programs use commandline arguments for wavespeed model input Please see the demos in CWPROOT src demos Synthetic for further information Also a number of the other demos use these programs for synthetic data generation 6 4 Delaunay Triangulation More sophisticated methods of synthetic data generation use assumptions regarding the nature of the medium as represented by the input wavespeed profile data format to expedite computations of the synthetic data One such method is triangulation via the Delaunay method 6 5 TETRAHEDRAL METHODS 71 6 4 1 Triangulated Model Building There are two way of making triangulated models The first is to explicitly input boundary coordinates and wavespeed actually sloth values with trimodel The second is to make a uniformly sampled model perhaps with one of the model building utilities above and then use uni2tri to convert the uni formly sampled model to a triangulated model Please note that this will work better if the wavespeed model is smoothed prior to conversion These programs are e TRIMODEL make a triangulated sloth 1 velocity squared model e UNI2TRI convert UNIformly sampled model to a TRlangulated model e TRI2UNI convert a TRlangulated model to UNIformly sampled model 6 4 2 Synthetic Seismic Data in Triangulated Media Several programs make use of triangulated models to create ray tracing or ray trace based synthetic seism
80. e non rewinding device On an RS6000 this would be something like dev rmtx 1 see man mt for details 3 If this still doesn t work then try dd if dev rmtx of temps bs 32767 conv noerror Here dev rmtx not the real name of the device it varies from system to system is your regular rewinding tape device In the option bs 32767 we gave the right blocksize 216 1 for an IBM RS6000 Try bs 32765 21 1 on a SUN This will dump the entire contents of the tape onto a single file Question 16 How do I write multiple SEG Y files onto a tape Answer 16 Here is a shell script for writing multiple files on a tape bin sh DEV dev nrxtO non rewinding tape device mt f DEV rewind 359 jmax 40 while test j ne jmax do j expr j 1 echo writing tape file j segywrite tape DEV bfile b j hfile h j verbose 1 buff 0 lt ozdata j done exit 0 9 4 Geometry Setting Question 17 How do I do geometry setting in SU Answer 17 There is a common seismic data manipulation task that often is called geometry setting in commercial packages in which the user converts information in the survey observers logs into values in the trace headers The CWP SU package does indeed have provisions for getting and setting header fields as well as computing a third header field from one or two other header fields The programs that you need to use for this are sugethw SU get header word sush
81. e pattern transferred before ftp actually does it ftp gt bye to exit from ftp A 2 Requirements for installing the package The only requirements for installing the package are 1 A machine running the UNIX operating system 2 An ANSI C compiler 3 A version of make which supports include files 4 16 60 megabytes depending on system of disk space for the source and compiled binary If space is an issue then the compiled binaries may be stripped by cd ing to CWPROOT bin and typing strip The package has been successfully installed on e IBM RS6000 e SUN SPARC STATIONS e HP 9000 series machines e HP Apollo e NeXT e Convex e DEC e Silicon Graphics e PC s running LINUX PRIME TIME SCO FREE BSD ESIX and NeXTSTEP 486 There are README files in the distribution with special notes about some of these platforms We depend on the SU user community to alert us to installation problems so if you run into difficulties please let us know The distribution contains a series of files that detail the installation process Read them in the following order LEGAL_STATEMENT license legal statement README_BEFORE_UNTARRING initial information README_FIRST general information README_TO_INSTALL installation instructions Portability README_ portability information for various platforms README_GETTING_STARTED how to begin using the codes A 3 A QUICK TEST 107 10 20 30 0 057
82. e requestdoc subroutine call specifies the circumstances under which self doc will be echoed to the user The argument 1 applies to the typical program that uses only standard input i e lt to read an SU trace file Use 0 for codes that create synthetic data like suplane and 2 for codes that require two input files we could say et cetera but there are no existing SU mains that require three or more input files 8 This is typical code for reading parameters from the command line Interpret it like this If the user did not specify a value then use the default value The subroutine must be type specific here we are getting an integer parameter 9 Read the first trace exit if empty The subroutine fgettr knows about the SU trace format Usually the trace file is read from standard input and then we use gettr which is a macro based on fgettr defined in su h Note that this code implies that the first trace is read into the trace buffer here called tr therefore we will have to process this trace before the next call to fgettr 10 We ve read that first trace because we need to get some trace parameters from the first trace header Usually these are items like the number of samples tr ns and or the sampling interval tr dt that by the SEGY Y standard are the same for all traces 11 Since the first trace has been typically read before the main processing loop starts we use a do while th
83. eader fields For example making test data with suplane suplane gt data su suedit data su yields the following 32 traces in input file tracl 32 tracr 32 offset 400 ns 64 dt 4000 gt prompt for interactive use The commands that may be used interactively in suedit and suxedit may be seen by typing a question mark at the prompt For example 32 traces in input file tracl 32 tracr 32 offset 400 ns 64 dt 4000 gt n read in trace n lt CR gt step next trace step gt 1 prev trace step gt 1 dN adv N traces step gt N percentiles r ranks p ni n2 tabplot key val modify field E print this file q quit 3 5 SETTING EDITING AND VIEWING TRACE HEADER FIELDS 41 This program allows the user to view traces as a tabplot of the data sample values or view or change individual header values The program suxedit is similar to suedit with the addition of X windows graphics for plotting traces suxedit diskfile open for possible header modification if writable suxedit lt diskfile open read only suxedit data su 32 traces in input file tracl 32 tracr 32 offset 400 delrt 5 ns 64 dt 4000 gt n read in trace n lt CR gt step next trace step gt 1 prev trace step gt 1 dN adv N traces step gt N percentiles r ranks p ni n2 tabplot g tri tr2 opts wiggle plot f wig plot Fourier Transf key val modify field print this file q quit
84. ed Questions This chapter addresses questions often asked by new SU users Some answers refer to the directory CWPROOT We use this symbolic name for the directory that contains the CWP SU source code include files libraries and executables You are asked to specify this directory name during the SU installation procedure 9 1 Installation questions Complete information about the installation process is found in the README files supplied with the distribution Here we discuss only some commonly found installation problems Question 1 I get error messages about missing fgetpos and fsetpos routines even though I am using the GCC compiler How do I get around this problem Answer 1 We ve seen this problem most often with older SUN OS 4 xx pre SOLARIS These SUN systems may not have the fgetpos and fsetpos subroutines defined Because these two routines are not currently used in the SU package we have modified the installation process to permit the user to define a compile time flag to circumvent this problem Please uncomment the OPTC line in the paragraph in Makefile config that looks like this For SUN installing with GCC compiler but without GLIBC libraries HOPTC 0 DSUN_A DSUN and do a make remake Question 2 I get error messages regarding missing strtoul and or strerror routines even though I am using the GCC compiler How do I get around this problem Answer 2 Again this is most often seen with the older SUN OS The
85. empnumber END DO CLOSE 99 FTNUNSTRIP convert C binary floats to Fortran style floats However another possibility is to make fake Fortran floats with a C program Such a program is ftnunstrip This program assumes that the record length is constant throughout the input and output files In fortran code reading these floats the following implied do loop syntax would be used DO i 1 n2 READ 10 someARRAY j j 1 n1 END DO Here n1 is the number of samples per record n2 is the number of records 10 is some default file fort 10 for example which is opened as form unformatted Here someArray j is an array dimensioned to size nl Please note that the Fortran style of having BOR and EOR markers is smart if used properly but is stupid if used incorrectly The Fortran READ statement finds out from the BOR marker how many bytes will follow reads the number of values specified keeping track of the number of bytes When it finishes reading it compares the number of bytes read to the number of bytes listed in the EOR value and can effectively trap errors in bytes read or premature EOR Because there is an additional sizeof int usually 4 bytes at the beginning and end of every record it is smart to have as few records as is necessary The worst case scenario is to 28 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS have every value of data be a record meaning that the size of the file could be 2 3 BOR and EOR markers an
86. endian or low byte systems are systems that are based on Intel and Dec chips The program swapbytes is provided to do this for a variety of data format types but not SU data For example swapbytes lt data bin in float gt data swap will swap the bytes in a file of containing C style floating point numbers 3 4 2 SUSWAPBYTES Swap the Bytes of SU Data If you transport SU data data with SU headers between systems you have to swap both the data and the SU headers The program suswapbytes is provided to do this The command sequence 32 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS suswapbytes lt data su format 0 gt data su swapped will swap data in the SU format from a machine of the reverse endian to the byte order of your system The command sequence suswapbytes lt data su format 1 gt data su swapped will swap data in the SU format that is in your system s byte order to the opposite byte order You would use this if you were transporting your SU data from you system to another system of the opposite byte order 3 5 Setting Editing and Viewing Trace Header Fields Seismic data can have a large number of parameters associated with it In SU data following the example of the SEG Y format the values of these parameters are stored in the header fields of the traces There are a number of programs which access the header fields allowing you to set view and modify those fields for a variety of purposes The tasks of
87. er e TRANSP TRANSPose an n1 by n2 element matrix 3 1 READING AND WRITING DATA TO AND FROM TAPES 21 3 1 1 The SEGY format and the SU data format The data format that is expected by all programs in the CWP SU package whose names begin with the letters su with the exception of the program subset consists of SEGY traces written in the native binary format of the machine you are running the programs on To understand what this phrase means we must understand what the SEGY standard is In the early 1980 s the most common data storage format was SEG Y This is the Society of Exploration Geophysicists Y format which is described in the SEG s publication Digital Tape Standards The format is still widely used today though there is no guarantee that the format is used by the book The SEGY data format consists of 3 parts The first part is a 3200 byte EBCDIC card image header which contains 40 cards i e 40 lines of text with 80 characters per line worth of text data describing the tape The second part is a 400 byte binary header containing information about the contents of the tape reel The third portion of the SEG Y format consists of the actual seismic traces Each trace has a 240 byte trace header The data follow written in one of 4 possible 32 formats in IBM floating point notation as defined in IBM Form GA 22 6821 Note this IBM format is not the common IEEE format found on modern IBM PC s The SU data
88. f the Center for Wave Phenomena CWP at the Colorado School of Mines CSM conceived a bold plan This plan was to create a seismic processing environment for Unix based systems written in the C language that would extend the Unix operating system to seismic processing and research tasks Furthermore they intended that the package be freely available as full source code to anyone who would want it They began with a package called SY started by Einar Kjartansson while he was a gradu ate student at Jon Claerbout s Stanford Exploration Project SEP in the late seventies and improved while he was a professor at the University of Utah in the eighties In 1984 Einar returned to SEP to baby sit the students and Jon s house while Claerbout went for a summer vacation Einar introduced SY to Shuki Ronen then a graduate student at SEP a day before Claerbout returned from vacation and Einar left back to Utah Ronen further developed SY from 1984 to 1986 Other students at SEP started to use it and contributed code and ideas SY was inspired by much other software developed at SEP and benefited from the foundations laid by Clarbout and many of his students Rob Clayton Stew Levin Dave Hale Jeff Thorson Chuck Sword and others who pioneered seismic processing on Unix in the seventies and early eighties In 1986 when Ronen accepted a one year visiting professorship at CSM he was encouraged by Claerbout to disseminate whatever SEP ideas and software he
89. f the synthetic wave information which propagates in that wavespeed profile Because of the intimate relationship between seismic modeling and seismic processing background wavespeed profiles created for modelling tasks may also be useful for processing tasks Of course if some simple assumptions are made it may be possible for background wavespeed information to be built into the modeling program 6 1 Background Wavespeed Profiles There are many approaches to creating background wavespeed profiles For many processes it may be that a simple array of floating point numbers each representing the wavespeed slowness 1 wavespeed or sloth slowness squared on a uniformly sampled grid will be sufficient However more advanced techniques may involve wavespeed profile generation in triangulated or tetrahedrized media 6 2 Uniformly Sampled Models In Seismic Unix there are several programs which may be used to generate background wavespeed profile data Often such data need to be smoothed These programs are e UNISAM UNIformly SAMple a function y x specified as x y pair e UNISAM2 UNIformly SAMple a 2 D function f x1 x2 e MAKEVEL MAKE a VELocity function v x y z e UNIF2 generate a 2 D UNIFormly sampled velocity profile from a layered model In each layer velocity is a linear function of position 69 70 CHAPTER 6 SEISMIC MODELING UTILITIES e SMOOTHINT2 SMOOTH non uniformly sampled IN Terfaces via the damped leas
90. format is based on the trace portion of the SEGY format The primary difference between the SEGY traces and SU traces is that the data portion of the SU format are floats written in the native binary float format of the machine you are running SU on SU data consists of the SEGY traces only The ebcdic and binary reel headers are not preserved in the SU format so simply redirecting in a SEGY file will not work with any SU program To convert SEGY data into a form that can be used by SU programs you will need to use segyread 3 1 2 SEGYREAD Getting SEG Y data into SU The program segyread is used to convert data from the SEGY format to the SU format If you type segyread You will see the selfdoc for this program When reading a SEGY tape or datafile you will need to be aware of the byte order endian of the machine you are running on The so called big endian or high byte IEEE format is found on SGI SUN IBM RS6000 and all Motorola chip based systems The little endian or low byte systems are systems that are based on Intel and Dec chips You will also need to know what Unix device your tape drive is A typical execution of segyread on a big endian machine looks like this segyread tape dev rmt0 verbose 1 endian 1 gt data su More often you will have to use the following segyread tape dev rmt0 verbose 1 endian 1 segyclean gt data su for reading a tape on a big endian platform There are optional heade
91. frequency axis Conversely if band is too small then the stripes will be parallel to the time axis Examples suvibro sugabor suximage suvibro sugabor suxmovie n1 n2 n3 because suxmovie scales it s amplitudes off of the first panel may have to experiment with the wclip and bclip parameters suvibro sugabor supsimage your local PostScript utility If you compare this output to the output from typing sudoc sugabor You will see the same output as above preceeded by a line showing the location of the source code and followed by the additional paragraphs Credits CWP John Stockwell Oct 1994 Algorithm This programs takes an input seismic trace and passes it through a collection of truncated Gaussian filters in the frequency domain The bandwidth of each filter is given by the parameter band The decay of these filters is given by alpha and the number of filters is given by nfilt fmax fmin band The result upon inverse Fourier transforming is that nfilt traces are created with each trace representing a different frequency band in the original data For each of the resulting bandlimited traces a quadrature i e pi 2 phase shifted trace is computed via the Hilbert transform The bandlimited trace constitutes a complex trace with the bandlimited trace being the real part and the quadrature trace being the imaginary part The instantaneous amplitude of each bandlimited trace is the
92. hat the bandwidth will change 9 6 General This section addresses general questions about the SU package Question 19 What are these funny words gelev selev fidr etc that I see in various places Answer 19 These are the keywords that are required for many of the codes They refer to SU Segy header fields Type sukeyword o to see the whole list Type sukeyword keyword to see the listing for an individual keyword Question 20 What do the terms little endian and big endian and mean Answer 20 There are two IEEE binary formats called respectively little endian and big endian These are also called high byte and low byte respectively These refer to the byte order in the bitwise representation of binary data The following platforms are little endian DEC and Intel based PC s The other common platforms are big endian IBM RS6000 Silicon Graphics NeXT black hardware SUN HP PowerPC any Motorola chip based platform Question 21 Why are CWP SU releases given by integers 22 23 24 etc instead of the more familiar decimal release numbers 1 1 1 3 etc 9 6 GENERAL 93 Answer 21 The CWP SU release numbers are chosen to correspond to the SU NEWS email messages The individual codes in the package have traditional decimal release numbers assigned by RCS but these are all different The package changes in incremental but non uniform ways so the standard notation seems inappr
93. he current release xx Take the files 1 README_BEFORE_UNTARRING 2 README_UPDATE 3 untar_me _first xx tar Z 4 update yy to xx tar Z 5 update list If you find that ftp times out during the transmission of the files the package is available in smaller pieces in the subdirectory outside_usa For readers who are not familiar with anonymous ftp an annotated transaction listing follows in sec tion A 1 A 1 Obtaining files by anonymous ftp Type ftp 138 67 12 4 138 67 12 4 is our ftp site username anonymous your username is anonymous password yourname your machine name type anything here ftp gt this is the prompt you see when you are in ftp You are now logged in via ftp to the CWP anonymous ftp site You may type 105 106 APPENDIX A OBTAINING AND INSTALLING SU ftp gt ls to see the contents of the directories ftp gt cd dirname to change directories to dirname ftp gt binary toset binary mode for transferring files You must do this before you try to transfer any binary file This includes all files with the form some_name tar Z extension ftp gt get filename to transfer filename from our site to your machine ftp gt mget pattern to transfer all files with names of the pattern For example ftp gt mget tar Z will transfer all files with the form of name tar Z to your machine You will be asked whether you really want each file of this nam
94. he graphics The way to get around this problem is to set perc 99 in the graphics program For example suximage lt sudata perc 99 amp This will clip data values with size in the top 1 percentile of the total data Question 8 I am trying to plot data with the pswigb or pswigp or xwigb or program I know that I have data with n1 NSAMP and n2 NTRACES but when I plot I find that I have to set n1 NSAMP 60 for the plot to look even remotely correct Why is this Answer 8 It is likely that you are trying to plot with the wrong tool The input data format of the programs pswigb pswigp pscontour pscube psmovie xwigb xgraph and xmovie expect data to consist of simple floating point numbers If your data are SU data SEG Y traces then there is an additional header at the beginning of each trace which on most computer architectures is the same number 240 of bytes as the storage for 60 floats To plot these data use respectively supswigb supswigp supscontour supscube supsmovie suxwigb suxgraph or suxmovie Also it is not necessary to specify the dimensions of the data for these latter programs The su versions of the codes determine the necessary information from the appropriate header values In fact that is all they do the actual graphics is handled by the version without the su prefix Question 9 I want to check the size of a file to see if it has the right number of values but I am not sure how to take the
95. header into account How is this done 88 CHAPTER 9 ANSWERS TO FREQUENTLY ASKED QUESTIONS Answer 9 If the file consists of simple floating point numbers then the size in bytes equals the size of a float times the number of samples SIZE 4 N_SAMP The SU data SEG Y traces also have a header 240 bytes per trace giving the total number of bytes as 240 4 N_SAMP N_TRACES The byte count computed in this way is the number that the UNIX command 1s 1 shows Caveats The above calculations assume that you have the conventional architecture and that the header definition in segy h has not been altered Watch out as machines with 64 bit word size become common Question 10 I have some data in Fortran form and tried to convert it to SU data via the following suaddhead lt data fortran ns N_SAMP ftn 1 gt data su but this did not work properly I am sure that my fortran data are in unformatted binary floats What should I do Answer 10 There are different ways of interpreting the term unformatted with regard to fortran data Try ftnstrip lt data fortran suaddhead ns N_SAMP gt data su The program ftnstrip can often succeed in converting your fortran data into C like binary data even when the ftn 1 option in suaddhead fails Note the program ftnunstrip may be used to take C style binary data and convert it to Fortran form Question 11 J just successfully installed the CWP SU package but when I try to run the dem
96. ic in some way are constant for each trace or vary linearly across a gather then you don t have to use the infile option You may simply give the necessary values to sushw See the selfdocs for sushw and suchw for examples of these 92 CHAPTER 9 ANSWERS TO FREQUENTLY ASKED QUESTIONS 9 5 Technical Questions Question 18 I want to resample my data so that I have half as many traces and half as many samples How do I do that Answer 18 To resample data you must do the following 1 Check that you won t have aliasing Do this by viewing the amplitude spectra of your data Do this with suspecfx suspecfx lt data su suxwigb 2 If the bandwidth of your data extends beyond the new nyquist frequency of your data which in this example will be half of the original nyquist frequency then you will have to filter your data to fit within its new nyquist bandwidth Do this with sufilter sufilter lt data su f f1 f2 f3 f4 amps 0 1 1 0 gt data filtered su Here the f1 f2 f3 f4 are the filter corner frequencies and amps 0 1 1 0 indicate that the filter is a bandpass filter 3 Now you may resample your data with suresamp suresamp lt data filtered su nt NTOUT dt DTOUT gt data resampled su For your case NTOUT is 1 2 of the original number of samples and DTOUT is twice the time sampling interval in seconds of that in the original data Your output data should look quite similar to your input data with the exception t
97. ields set as longs at bytes 181 and 185 The following usage of segyread segyread tape remap d1 d2 gelev selev byte 73f 77f 1811 1851 gt The floats at 73 and 77 are mapped to dl and d2 while the long integers at 181 and 185 are mapped to gelev and selev which are integers in the SU format By selecting compatible destination fields no precision is lost 3 1 4 SEGYWRITE Writing an SEGY Tape or Diskfile The companion program to segyread is segywrite This program permits data to be written either to a tape or a diskfile in a number of variations on the SEGY format This program is useful for putting data into a form that can be read by commercial seismic packages Before showing examples of how segywrite is used there are several preprocessing steps that must be discussed in preparation for actually writing a tape 3 1 5 SEGYHDRS make SEG Y ascii and binary headers for segywrite To write a tape in exactly the SEGY format as specified by the SEG s Digital Tape Standards book you will need to supply the ASCII and binary tape reel header files which will become the EBCDIC and binary tape reel headers in the SEGY tape or file These are the files header and binary created by segywrite If you don t have the binary and header files then you must create them with the program segyhdrs pronounced SEG Y headers The command segyhdrs lt data su will write the files header and binary in
98. ight t this_year sugendocs suhelp suname sukeyword XK AA AX AX XX XA XA XA XA XA XX XX XX XX XX X susyncz susynlv susynlvcw SUSYNVXZ SUSYNVXZCS triray triseis wkbj trimodel uni2tri unif2 unisam unisam2 velconv suspike trip Mesa 3D item viewer3 Mesa 3D item vtlvz xy2z time_now todays_date updatedoc updatedocall updatehead upfort usernames varlist wallsec walltime weekday zap XK XX XX XA XX A XA A XX B 4 SUKEYWORD LIST THE SU DATATYPE SEGY KEYWORDS 127 Go to top B 4 SUKEYWORD list the SU datatype SEGY Keywords The following is the listing put out by typedef struct 1 segy trace identification header int tracl trace sequence number within line int tracr trace sequence number within reel int fldr field record number int tracf trace number within field record int ep energy source point number int cdp CDP ensemble number int cdpt trace number within CDP ensemble short trid trace identification code seismic data dead dummy time break uphole sweep timing water break N optional use N 32 767 0 XAO 0M SuU0Ne ll co l Following are CWP id flags 9 autocorrelation 10 Fourier transformed no packing xr 0 xi 0 xr N 1 xi N 1 11 Fourier transformed unpacked Nyquist xr 0 xi 0 xr N 2 xi N 2 12 Fourier transformed packed Nyquist eve
99. ile displays the file on the standard output and cat file1 file2 gt file3 More You need to know a bit more UNIX lore to use SU efficiently we ll introduce these tricks of the trade in the context of the examples discussed later in this chapter 8 2 Understanding and using SU shell programs The essence of good SU usage is constructing or cloning UNIX shell programs to create and record processing flows In this section we give some annotated examples to get you started 8 2 1 A simple SU processing flow example Most SU programs read from standard input and write to standard output Therefore one can build complex processing flows by simply connecting SU programs with UNIX pipes Most flows will end with one of the SU plotting programs Because typical processing flows are lengthy and involve many parameter settings it is convenient to put the SU commands in a shell file Remark All the UNIX shells Bourne sh Cshell csh Korn ksh include a programming language In this document we exclusively use the Bourne shell programming language Our first example is a simple shell program called Plot The numbers in square brackets at the end of the lines in the following listing are not part of the shell program we added them as keys to the discussion that follows the listing bin sh 1 Plot Plot a range of cmp gathers Author Jane Doe Usage Plot cdpmin cdpmax data HOME data cmgs 2 8 2 UNDERST
100. in 5 max 10 sugethw key tracl more tracl 5 tracl 6 tracl 7 tracl 8 tracl 9 tracl 10 On a large dataset the count parameter should be used instead of setting the max value If you set an explicit max value suwind will have to go through the entire dataset to capture all possible traces with values between the min and max value because the program assumes that multiple occurrences of trace labeling are possible For example compare suplane ntr 100000 suwind key tracl min 5 max 10 sugethw tracl more it s ok to type control c after a few minutes with suplane ntr 100000 suwind key tracl min 5 count 5 sugethw tracl more where suplane has been set to create 100000 traces in each case More sophisticated windowing decimating data for example Pass every j th trace j 1 s 0 based at s if key s j 0 can be illustrated with suplane data by showing every 2nd trace suplane suwind key tracl j 2 sugethw key tracl more tracl 2 tracl 4 tracl 6 4 4 EDITING SU DATA 53 tracl 8 tracl 10 or by every 2nd trace based at 1 suplane suwind key tracl j 2 s 1 sugethw key tracl more tracl 1 tracl 3 tracl 5 tracl 7 tracl 9 Accepting and rejecting traces is also possible with suwind reject none Skip traces with specified key values accept none Pass traces with specified key values see notes The reject parameter is a straightforward rejecting of nu
101. ing e time varying filtering The programs that are provided to meet these needs are e SUFILTER applies a zero phase sine squared tapered filter e SUBFILT apply Butterworth bandpass filter e SUACOR auto correlation e SUCONV SUXCOR convolution correlation with a user supplied filter e SUPEF Wiener predictive error filtering e SUSHAPE Wiener shaping filter e SURESAMP Resample in time 66 CHAPTER 5 GENERAL OPERATIONS ON SU DATA e SUFRAC take general fractional time derivative or integral of data plus a phase shift Input is TIME DOMAIN data e SUMEDIAN MEDIAN filter about a user defined polygonal curve with the distance along the curve specified by key header word e SUTVBAND time variant bandpass filter sine squared taper 5 4 1 SUFILTER applies a zero phase sine squared tapered filter The program sufilter provides a general purpose zero phase filtering capability for the usual tasks of bandpass bandreject lowpass highpass and notch filtering Examples of each of these using sufilter data are provided suplane sufilter f 10 20 30 60 amps 0 1 1 0 suxwigb title 10 20 30 60 hz bandpass suplane sufilter f 10 20 30 60 amps 1 0 0 1 suxwigb title 10 20 30 60 hz bandreject suplane sufilter f 10 20 30 60 amps 1 1 0 0 suxwigb title 10 20 hz lowpass amp suplane sufilter f 50 60 70 amps 1 0 1 suxwigb title 60 hz notch amp The filter is polygonal with the corners
102. ing The first way would be to append one dataset to another so that the traces from the second file simply follow the traces of the first file This is done with the Unix cat command via cat datal su data2 su gt data3 su In addition it may be necessary to renumber the traces via cat datal su data2 su sushw key tracl a 1 gt data3 su so that the tracl parameter is monotonically increasing The second way of appending one dataset to another is to vertically append each trace of the second dataset to the end of the first dataset This is done via suvcat suvcat datal su data2 su gt data3 su In this case no modification of the header fields should be necessary 4 4 EDITING SU DATA 57 4 4 6 SUVLENGTH Adjust Variable Length Traces to a Common Number of Samples Sometimes the data consists of traces which have different numbers of samples on each trace The program suvlength We can construct an example of this with suplane data suplane nt 64 gt datal su suplane nt 32 gt data2 su cat datal su data2 su gt data3 su Attempts to use any SU program on the resulting file data3 su will probably result in failure because most SU programs require that the number of samples be constant on a panel of data Applying suvlength fixes this problem suvlength ns 64 lt data3 su gt data4 su suxwigb lt data4 su title Test of suvlength amp by making all of the traces the same le
103. ing offsets in prepared data SUDIVSTACK Diversity Stacking using either average power or peak power within windows SUVELAN SUNMO Velocity Analysis and Normal Move out Correction SUVELAN compute stacking velocity semblance for cdp gathers SUNMO NMO for an arbitrary velocity function of time and CDP Please see the demos in CWPROOT src demos Velocity_Analysis and CWPROOT src demos NMO for further information 7 3 SUDMOFK SUDMOTX SUDMOVZ Dip Moveout Cor rection Dip moveout is a data transformation which converts data recorded with offset to zero offset data The following programs 73 74 CHAPTER 7 SEISMIC PROCESSING UTILITIES e SUDMOFK DMO via F K domain log stretch method for common offset gathers e SUDMOTX DMO via T X domain Kirchhoff method for common offset gathers e SUDMOVZ DMO for V Z media for common offset gathers perform this operation 7 4 Seismic Migration The subject of seismic migration is one of the most varied in seismic data processing Many algorthms have been developed to perform this task Methods include Kirchhoff Stolt Finite Difference Fourier Finite Difference and several types of Phase Shift or Gazdag Migration Please see the demos in CWPROOT src demos Migration for further information 7 4 1 SUGAZMIG SUMIGPS SUMIGPSPI SUMIGSPLIT Phase Shift Migration e SUGAZMIG SU version of Jeno GAZDAG s phase shift migration for zero offset data e SUMIGPS MIGration by
104. ing supef and other tools The demos include commands for systematically examining the effect of the filter parameters using loops e The Sorting Traces Tutorial is an interactive script that reinforces some of the basic UNIX and SU lore discussed in this document The interactivity is limited to allowing you to set the pace Such tutorials quickly get annoying but we felt that one such was needed to cover some issues that didn t fit into our standard demo format There is also a standard but less complete demo on this topic e The next step is to activate the Selecting_Traces Demo Then proceed to the NMO Demo Beyond that visit the Demo directories that interest you The demos directory tree is still under active development please let us know if the demos are helpful and how they can be improved 2 9 Other Help Mechanisms e SUKEYWORD List SU Header Field Key Words Many of the SU programs that draw on header field information have the parameter key listed in their selfdocs with the reference to keywords The SU keywords are based on the SEGY trace header fields This will be explained later in the sections on tape reading and data format conversion To find out what these header fields are and what they stand for in the SU data type type 2 9 OTHER HELP MECHANISMS 17 sukeyword o Please see Appendix B for the full text of the output See Section 3 5 3 for details on the usage of this command A number of
105. interest are e adding SU headers e stripping SU headers off of data and then pasting them back on identifying SU keywords viewing the range of SU header values setting specified SU header fields e computing a third header field from the values of two given fields getting the values of header fields e editing specific header fields all of which are necessary and may come under the heading of geometry setting The following list of programs will be discussed in this chapter e SUADDHEAD put headers on bare traces and set the tracl and ns fields e SUSTRIP remove the SEGY headers from the traces e SUPASTE paste existing SEGY headers on existing data e SUKEYWORD guide to SU keywords in segy h e SURANGE get max and min values for non zero header entries e SUSHW Set one or more Header Words using trace number mod and integer divide to compute the header word values or input the header word values from a file e SUCHW Change Header Word using one or two header word fields 3 5 SETTING EDITING AND VIEWING TRACE HEADER FIELDS 33 e SUGETHW Get the Header Word s in SU Data e SUEDIT examine segy diskfiles and edit headers e SUXEDIT examine segy diskfiles and edit headers Some of these items were discussed in the previous section but for completeness let s recap what these programs do with a bit more information 3 5 1 SUADDHEAD add SU SEG Y style Trace Headers To add headers to a dat
106. isting bin sh dmo set x 1 set parameters input cdp201t0800 2 8 2 UNDERSTANDING AND USING SU SHELL PROGRAMS 79 temp dmocogs output dmocmgs smute 1 7 vnmo 1500 1550 1700 2000 2300 2600 3000 3 tnmo 0 00 0 40 1 00 2 00 3 00 4 00 6 00 sort to common offset nmo dmo inverse nmo sort back to cmp susort lt input offset cdp 4 sunmo smute smute vnmo vnmo tnmo tnmo 5 sudmofk cdpmin 201 cdpmax 800 dxcdp 13 335 noffmix 4 verbose 1 6 sunmo invert 1 smute smute vnmo vnmo tnmo tnmo gt temp 7 susort lt temp cdp offset gt output 8 Discussion of numbered lines The core of the shell program lines 5 7 is recognized as the typical dmo process crude nmo dmo and then inverse nmo The dmo processing is surrounded by sorting operations lines 4 and 8 Here is a detailed discussion of the shell program keyed to the numbers appended to the listing see also the discussion above for the Plot shell 1 Set a debugging mode that asks UNIX to echo the lines that are executed You can comment this line off when its output is no longer of interest An alternate debugging flag is set v which echos lines as they are read by the shell interpreter You can use both modes at once if you like 2 This line and the next two lines set filenames that in this case are in the same directory as the shell program itself Again the reason for using parameters here is to make it easy to clone the she
107. ists environmental engineers software develop ers and others It is used by scientific staff in both small geotechnical companies and major oil and gas companies and by academics and government researchers both as a seismic data processing and software development environment 1 1 What SU is The SU package is free software meaning that you may have unrestricted use of the codes for both processing and software development provided that you honor the license that appears at the beginning of this manual and as the file LEGAL_STATEMENT in the current release of the package This latter file takes precedence The package is maintained and expanded periodically with each new release appearing at 3 to 6 month intervals depending on changes that accumulate in the official version here at CWP The package is distributed with the full source code so that users can alter and extend its capabilities The philosophy behind the package is to provide both a free processing and development environment in a proven structure that can be maintained and expanded to suit the needs of a variety of users The package is not necessarily restricted to seismic processing tasks however A broad suite of wave related processing can be done with SU making it a somewhat more general package than the word seismic implies SU is intended as an extension of the Unix operating system and therefore shares many characteristics of the Unix including Unix flexibility a
108. ith the lt operator and similarly the output data set outdata receives the data because of the gt operator The output of sufilter is connected to the input of sugain by use of the operator The strings with the signs illustrate how parameters are passed to SU programs The program sugain receives the assigned value 2 0 to its parameter tpow while the program sufilter receives the assigned four component vector to its parameter f To find out what the valid parameters are for a given program we use the self doc facility By the way space around the UNIX redirection and pipe symbols is optional the example shows one popular style On the other hand spaces around the operator are not permitted The first four symbols in Table 8 1 are the basic grammar of UNIX the final lt lt entry is the symbol for the less commonly used here document redirection Despite its rarity in interactive use SU shell programs are significantly enhanced by appropriate use of the lt lt operator we will illustrate this below 75 76 CHAPTER 8 PROCESSING FLOWS WITH SU Many built in UNIX commands do not have a self documentation facility like SU s instead most do have man pages For example man cat CAT 1 UNIX Programmer s Manual CAT 1 NAME cat catenate and print SYNOPSIS cat u n s v file DESCRIPTION Cat reads each file in sequence and displays it on the stan dard output Thus cat f
109. l written in a little endian format On a big endian machine the command to read such a dataset would be segyread tape dev rmt0 verbose 1 endian 0 conv 0 segyclean gt data su will read the data Note that endian 0 is set to swap the bytes All of the bytes header and data are in the swapped format On a little endian machine the procedure is 3 1 READING AND WRITING DATA TO AND FROM TAPES 23 segyread tape dev rmt0 verbose 1 endian 1 conv 0 segyclean gt data su with endian 1 in this case preventing byteswapping In each case if we had a diskfile with some filename we would use tape filename Landmark BCM2D format in SEISWORKS Commercial seismic software can be sources of non standard SEGY formats In addition to non standard usage of the official header fields commercial variations on SEGY may employ definitions of parts of the optional SEGY header fields A remedy for this problem supplied by Matthias Imhoff of Virginia Tech is a remapping feature in segyread which allows nonstandard fields to be remapped into compatible locations in the SU header The options remap allows the destination SU header fields to be specified while byte specifies the byte location in the SEGY trace header and its data type For the example of Landmark BCM2D format header fields 73 and 77 are floats but these are int s in the standard SEGY format and are hence also int s in the SU format BCM2D also has to header f
110. lbert Transform amp This program is useful for instructional and testing purposes To see an example of trace attributes with suattributes it is necessary to make data which has a strong time frequency variability This is done here with suvibro which makes a synthetic vibroseis sweep Compare the following suvibro suvibro suvibro suvibro suxgraph title Vibroseis sweep amp suattributes mode amp suxgraph title Inst amplitude amp suattributes mode phase unwrap 1 0 suxgraph title Inst phase amp suattributes mode freq suxgraph title Inst frequency amp which show respectively instantaneous amplitude phase and frequency To see the synthetic vibroseis trace in the time frequency domain try the following suvibro sugabor suximage title time frequency plot amp The result is an image which shows the instantaneous or apparent frequency increasing from 10hz to 60hz with time exactly as stated by the default parameters of suvibro See the demos in CWPROOT src demos Time_Freq_Analysis and CWPROOT src demos Filtering Sugabor for further information 5 3 RADON TRANSFORM TAU_P FILTERING 65 5 3 Radon Transform Tau_P Filtering The Radon or tau p transform as it is sometimes called in geophysical literature is useful for a variety of multiple suppression and other surgical data manipulation tasks The programs e SUTAUP forwared and inverse T X and F
111. lding 0 000 71 6 4 2 Synthetic Seismic Data in Triangulated Media 71 6 5 Tetrahedral Methods 71 7 Seismic Processing Utilities 73 7 1 SUSTACK SURECIP SUDIVSTACK Stacking Data 73 7 2 SUVELAN SUNMO Velocity Analysis and Normal Moveout Correction 73 7 3 SUDMOFK SUDMOTX SUDMOVZ Dip Moveout Correction 73 TA Seismic Migration Ll A AA ae ee A a adn 74 7 4 1 SUGAZMIG SUMIGPS SUMIGPSPI SUMIGSPLIT Phase Shift Mi PALIO a AD OR Stes Et HOR eed Stl 74 7 4 2 SUKDMIG2D SUMIGTOPO2D SUDATUMK2DR SUDATUMK2DS 2D Kirchhoff Migration and Datuming 74 7 4 3 SUMIGFD SUMIGFFD Finite Difference Migration 74 7 4 4 SUMIGTK Time Wavenumber Domain Migration 74 7 4 5 SUSTOLT Stolt Migration e o 74 8 Processing Flows with SU 75 SL SU and UND potest aha A eee tty el eed Bee BOE ey eg otek 75 8 2 Understanding and using SU shell programs 2 000 76 8 2 1 A simple SU processing flow example 2 00 76 8 2 2 Executing shell programs 2 2 2 0 0 e 78 8 2 3 A typical SU processing flow 2 0 00 ee ee 78 8 3 Extending SU by shell programming 2 020004 80 9 Answers to Frequently Asked Questions 85 9 1 Installation questions a 85 9 2 Data format questions 2 46 54 4 8 2e 4 E be we Re me Re es 86 9 3 Tape reading and writing 2 e a 89
112. le ARITHmetic perform simple arithmetic with binary files FINSTRIP convert a file of floats plus record delimiters created H2B convert 8 bit hexidecimal floats to binary KAPERTURE generate the k domain of a line scatterer for a seismic array MAKEVEL MAKE a VELocity function v x y z MKPARFILE convert ascii to par file format PRPLOT PRinter PLOT of 1 D arrays f x1 from a 2 D function f x1 x2 RAYT2D traveltime Tables calculated by 2D paraxial RAY tracing RECAST RECAST data type convert from one data type to another REGRID3 REwrite a ni3 ni2 ni1 GRID to a no3 no2 no1 3 D grid RESAMP RESAMPle the ist dimension of a 2 dimensional function f x1 x2 Please type suhelp or see Appendix B for the full text 2 3 The Selfdoc Program Self Documentation There are no Unix man pages for SU To some people that seems to be a surprise even a disappointment as this would seem to be a standard Unix feature which Seismic Unix should emulate The package does contain an equivalent mechanism called a selfdoc or self documentation feature This is a paragraph that is written into every program and arranged so that if the name of the program is typed on the commandline of a Unix terminal window with no options or redirects to or from files the paragraph is printed to standard error the screen For example sustack SUSTACK stack adjacent traces having the same key header word sustack lt input gt output Opti
113. le smooth2 unif2 vtlvz ftnunstrip prplot smooth3d unisam wkbj press return key to continue SU PROGRAMS self documented programs for SU data SU data is SEGY data run through segyclean bhedtopar sudmofkcw sukdmig3d suop sustkvel dtitosu sudmotivz sukdsyn2d suop2 sustolt segdread sudmotx sukfilter supack1 sustrip segyclean sudmovz sukfrac supack2 suswapbytes segyhdrs suea2df sukill supaste susyncz segyread suedit sulog supef susynlv segywrite sufdmod2 sumax supgc susynlvcw setbhed sufft sumean supickamp susynlvfti su3dchart sufilter sumedian suplane SUSYNVXZ suabshw suflip sumigfd suput SUSYNVXZCS suacor sufrac sumigffd suquantile sutab suaddhead sufxdecon sumiggbzo suradon sutaper suaddnoise sugabor sumigprefd suramp sutaup suamp sugain sumigpreffd surange sutsq suascii sugazmig sumigprepspi surecip suttoz suattributes suget sumigpresp sureduce sutvband 109 110 APPENDIX B HELP FACILILTIES suazimuth sugethw sumigps surelan suunpack1 subfilt suharlan sumigpspi suresamp suunpack2 suchart suhilb sumigpsti suresstat suvcat suchw suifft sumigsplit sushape suvelan sucommand suilog sumigtk sushift suvibro suconv suimp2d sumigtopo2d sushw suvlength sudatumfd suimp3d sumix susort suweight sudatumk2dr suinterp sumute suspecfk suwind sudatumk2ds suintvel sunmo suspecfx suxcor sudipfilt suinvvxzco sunormalize suspeck1k2 suxedit sudivcor suinvzco3d sunull suspike suzero sudivstack sukik2filter suocext sustack s
114. lf docs in doc Stripped UPDATEHEAD update doc Headers Headers all In CWPROOT src psplot shell MERGE2 put 2 standard size PostScript figures on one page MERGE4 put 4 standard size PostScript plots on one page In CWPROOT src su shell LOOKPAR show getpar lines in SU code with defines evaluated MAXDIFF find absolute maximum difference in two segy data sets RECIP sum opposing reciprocal offsets in cdp sorted data RMAXDIFF find percentage maximum difference in two segy data sets SUAGC perform agc on SU data SUBAND Trapezoid like Sin squared tapered Bandpass filter via SUFILTER SUDIFF SUSUM SUPROD SUQUO SUPTDIFF SUPTSUM SUDOC get DOC listing for code SUENV Instantaneous amplitude frequency and phase via SUATTRIBUTES SUFIND get info from self docs SUFIND get info from self docs SUGENDOCS generate complete list of selfdocs in latex form SUHELP list the CWP SU programs and shells SUKEYWORD guide to SU keywords in segy h SUNAME get name line from self docs UNGLITCH zonk outliers in data H HHH HHH HH HH HH H HOH Libs In CWPROOT src cwp lib ABEL Functions to compute the discrete ABEL transform AIRY Approximate the Airy functions Ai x Bi x and their respective ALLOC Allocate and free multi dimensional arrays ANTIALIAS Butterworth anti aliasing filter AXB Functions to solve a linear system of equations Ax b by LU BIGMATRIX Functions to manipulate 2 dime
115. ll for use with other data sets Those of us who work with only a few data sets at any given time find it convenient to devote a directory to a given data set and keep the shells used to process the data in that directory as documentation of the processing parameters used SU does not have a built in history mechanism 3 The dmo process requires a set of velocity time picks for the subsidiary nmo processes Because these picks must be consistent between the nmo and the inverse nmo it is a good idea to make them parameters to avoid editing mistakes Again note the format of SU parameter vectors comma separated strings with no spaces The nmo program sunmo will give an error message and abort if the vnmo and tnmo vectors have different lengths 4 Note that susort allows the use of secondary sort keys Do not assume that a secondary field that is initially in the right order will remain in that order after the sort if you care about the order of some secondary field specify it as this shell program does In this line we sort the data according to increasing offsets and then within each offset we sort according to increasing cdp number 5 The forward nmo step 6 The dmo step 7 The inverse nmo step 8 Sort back to cdp and have increasing offset within each cdp If you want to thoroughly understand this shell program your next step is to study the self docs of the programs involved sunmo SUNMO NMO for an
116. llustrates some real data processing to eliminate ground roll and first arrivals The demos in the Filtering subdirectories give instructions for accessing the data from the CWP ftp site The Deconvolution demo uses simple synthetic spike traces to illustrate both dereverberation and spiking decon using supef and other tools The demos include commands for systematically examining the effect of the filter parameters using loops The Sorting_Traces Tutorial is an interactive script that reinforces some of the basic UNIX and SU lore discussed in this document The interactivity is limited to allowing you to set the pace Such tutorials quickly get annoying but we felt that one such was needed to cover some issues that didn t fit into our standard demo format There is also a standard but less complete demo on this topic The next step is to activate the Selecting Traces Demo Then proceed to the NMO Demo Be yond that visit the Demo directories that interest you The demos directory tree is still under active development please let us know if the demos are helpful and how they can be improved As the user becomes more familiar with the logic of SU then he or she may feel free to run any of the other demos either in their original form or the user may modify the shell scripts to his or her own ends
117. lorado School of Mines during the late 1980 s when SU was ported to the modern workstation from its previous incarnation on graphics terminals So many faculty and students both at our Center and elsewhere have contributed to SU that it is impossible to list them all here However certain people have made such important contributions that they deserve explicit mention Einar Kjartansson began writing what is now called SU the SY package in the late 1970 s while still a graduate student at Jon Claerbout s Stanford Exploration Project SEP He continued to expand the package while he was a professor at the University of Utah in the early eighties In 1984 during an extended visit to SEP Einar introduced SY to Shuki Ronen then a graduate student at Stanford Ronen further developed SY from 1984 to 1986 Other students at SEP started to use it and contributed code and ideas SY was inspired by much other software developed at SEP and benefited from the foundations laid by Clarbout and many of his students Rob Clayton Stew Levin Dave Hale Jeff Thorson Chuck Sword and others who pioneered seismic processing on Unix in the seventies and early eighties In 1986 Shuki Ronen brought this work to our Center during a one year postdoctoral appointment at the Colorado School of Mines During this time Ronen aided Cohen in turning SU into a supportable and exportable product Chris Liner while a student at the Center contributed to many of the g
118. max or tmin and tmax will be to create a time gate which is to the nearest sample If you want to time gate to an arbitrary inter sample window then this is a problem in data resampling and suresamp is the program of choice 4 4 2 SUSORT sort on any SEGY header keywords One of the advantages of working in the Unix operating system is that when a superior Unix system call for a particular operation exists it is advantageous to use that call to perform the necessary task Such a task is sorting and the Unix sort command is just such a utility Susort takes advantage of the Unix system sort command to permit the sorting of traces by header field key work For example sorting data with values in ascending order for two fields cdp and offset would be done via 4 4 EDITING SU DATA 55 susort lt indata su gt outdata su cdp offset In decending order for offset and ascending order for cdp susort lt indata su gt outdata su cdp offset Note Only the following types of input output are supported Disk input to any output but pipe input to disk output Please see the demo in CWPROOT src demos Sorting_Traces for specific examples of trace sorting 4 4 3 SURAMP and SUTAPER tapering data values Many seismic processing algorithms will show spurious artifacts resulting from sharp edges on a dataset Tapering the amplitudes on the edges of a dataset is the one of the easiest ways of suppressing these artifact
119. mbered traces For example suplane suwind key tracl reject 3 8 9 sugethw key tracl more tracl 1 tracl 2 tracl 4 tracl 5 tracl 6 tracl 7 tracl 10 tracl 11 tracl 12 traces 3 8 and 9 are rejected The accept option is a bit strange it does not mean accept only the traces on the accept list It means accept these traces even if they would otherwise be rejected For example suplane suwind key tracl reject 3 8 9 accept 8 sugethw key tracl more 54 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT tracl 1 tracl 2 tracl 4 tracl 5 tracl 6 tracl 7 tracl 8 tracl 10 tracl 11 If you want to accept only the traces listed then you need to set max 0 suplane suwind key tracl accept 8 max 0 sugethw key tracl more tracl 8 Only trace 8 is passed in this example The count parameter overrides the accept parameter so you can t specify count if you want true unconditional acceptance See the demos in CWPROOT src demos Selecting Traces for specific examples Time gating The second issue windowing is time gating In fact when people want to window data they often want to do both trace and time gating Options for vertical windowing time gating tmin 0 0 min time to pass tmax from header max time to pass itmin 0 min time sample to pass itmax from header max time sample to pass nt itmax itmin 1 number of time samples to pass The result of setting either itmin and it
120. more of an art than a science This is true in general and is especially true for SU The variability of hardware formats as well as the variability of data format types makes the creation of a general tape reading utility a challenging if not impossible proposition The following programs are useful for the specialized data input and output tasks related to geophysical applications as well as to the internal SU data format e BHEDTOPAR convert a Binary tape HEaDer file to PAR file format e DTITOSU Convert ground penetrating radar data in the Sensors amp Software X dt1 GPR format to SU format e SEGDREAD read an SEG D tape e SEGYCLEAN zero out unassigned portion of header e SEGYREAD read an SEG Y tape e SEGYHDRS make SEG Y ascii and binary headers for segywrite e SEGYWRITE write an SEG Y tape e SETBHED SET the fields in a SEGY Binary tape HEaDer file e SUADDHEAD put headers on bare traces and set the tracl and ns fields e SUSTRIP remove the SEGY headers from the traces e SUPASTE paste existing SEGY headers on existing data The following programs are useful for general data input output and data type conversion which may also find use in tape reading e A2B convert ascii floats to binary e B2A convert binary floats to ascii e FTNSTRIP convert Fortran floats to C style floats e H2B convert 8 bit hexidecimal floats to binary e RECAST RECAST data type convert from one data type to anoth
121. n 10 gt gt junk1 su suplane suaddnoise sn 5 gt gt junki su suplane suaddnoise sn 3 gt gt junk1 su suplane suaddnoise sn 2 gt gt junk1 su suplane suaddnoise sn 1 gt gt junk1 su suxmovie lt junk1 su n2 32 title frame g loop 1 amp The final command has n2 32 set to show that there are 32 traces per frame of data The usage of q permits the frame number to be listed as part of the title and loop 1 runs the movie in a continuous loop To make the movie go faster or slower simply enlarge or shrink the window by clicking and dragging on the lower right corner of the plot Clicking the far right mouse button once will freeze the frame and clicking it a second time will start the movie again 4 1 4 PostScript Plotting Programs To complement our collection of X Windows plotting utilities are a collection of very similar PostScript codes The idea was to create PostScript plotting codes which would correspond to each of the X Windows codes listed above 4 1 5 PostScript Plotting of General Floating Point Data The programs that are used for PostScript plotting of general floating point data data without SU headers are e PSCONTOUR PostScript CONTOURing of a two dimensional function f x1 x2 e PSIMAGE PostScript IMAGE plot of a uniformly sampled function f x1 x2 e PSCUBE PostScript image plot of a data CUBE e PSGRAPH PostScript GRAPHer Graphs nfi pairs of x y coordinates
122. n N xr 0 xr N 2 xr 1 xi 1 1 xr N 2 1 1 xi N 2 1 128 APPENDIX B note the exceptional second entry odd N xr 0 xr N 1 2 xr 1 xi 1 xr N 1 2 1 xil N 1 2 1 xil N 1 2 note the exceptional second amp last entries 13 Complex signal in the time domain xr 0 xi 0 xr N 1 xi N 1 14 Fourier transformed amplitude phase a 0 p 0 a N 1 p N 1 15 Complex time signal amplitude phase a 0 p 0 a N 1 p N 1 16 Real part of complex trace from 0 to Nyquist 17 Imag part of complex trace from 0 to Nyquist 18 Amplitude of complex trace from 0 to Nyquist 19 Phase of complex trace from 0 to Nyquist 21 Wavenumber time domain k t 22 Wavenumber frequency k omega 23 Envelope of the complex time trace 24 Phase of the complex time trace 25 Frequency of the complex time trace 30 Depth Range z x traces 43 Seismic Data Vertical Component 44 Seismic Data Horizontal Component 1 45 Seismic Data Horizontal Component 2 46 Seismic Data Radial Component 47 Seismic Data Transverse Component 101 Seismic data packed to bytes by supack1 102 Seismic data packed to 2 bytes by supack2 short nvs number of vertically summed traces see vscode in bhed structure HELP FACILILTIES B 4 SUKEYWORD LIST THE SU DATATYPE SEGY KEYWORDS short nhs number of horizontally summed traces see vscode in bhed structure
123. n Number of Samples A A o a a he 57 5 General Operations on SU Data 59 5 0 7 SUADDNOISE Add noise to SU data o o a 59 5 0 8 SUGAIN Gaining to SU data e e 59 5 0 9 SUOP Unary Arithmetic Operations on SU Data 60 5 0 10 SUOP2 Binary Operations with SU data 61 5 1 Transform and Filtering Operations e e 62 5 1 1 Fourier Transform Operations 0 e 62 CONTENTS vil 5 1 2 1D Fourier Transforms e 62 5 1 3 2D Fourier Transforms 00 0 eee ee es 63 5 2 Hilbert Transform Trace Attributes and Time Frequency Domain 64 5 3 Radon Transform Tau_P Filtering o e a 65 5 4 1D Filtering Operations s eres s iea 0 02000 eee ee 65 5 4 1 SUFILTER applies a zero phase sine squared tapered filter 66 5 4 2 SUBFILT apply Butterworth bandpass filter 66 5 4 3 SUCONV SUXCOR convolution correlation with a user supplied filter 67 5 4 4 SUPEF Wiener predictive error filtering 67 5 4 5 SUSHAPE Wiener shaping filter o a 68 5 4 66 SURESAMP Resample Data in Time 68 6 Seismic Modeling Utilities 69 6 1 Background Wavespeed Profiles 2 0 a a e e 69 6 2 Uniformly Sampled Models 2 20 0 0 00 ee 69 6 3 Synthetic Data Generators 2 o a 70 6 4 Delaunay Triangulation 70 6 4 1 Triangulated Model Bui
124. n computed by computing the modulus of each complex trace 2 5 SUFIND FIND SU ITEMS WITH A GIVEN STRING 11 See Taner Koehler and Sheriff 1979 for a discussion of complex trace analysis The final output for a given input trace is a map of instantaneous amplitude as a function of time and frequency This is not a wavelet transform but rather a redundant frame representation References Dziewonski Bloch and Landisman 1969 A technique for the analysis of transient seismic signals Bull Seism Soc Am 1969 vol 59 no 1 pp 427 444 Taner M T Koehler F and Sheriff R E 1979 Complex seismic trace analysis Geophysics vol 44 pp 1041 1063 Chui C K 1992 Introduction to Wavelets Academic Press New York Trace header fields accessed ns dt trid ntr Trace header fields modified tracl tracr di f2 d2 trid ntr There is more information in the sudoc listing than in the selfdoc listing The selfdoc is intended as a quick reference whereas the sudoc listing can provide additional information that we do not necessarily want to see everytime we are say simply wanting to know what a particular parameter means for example 2 5 SUFIND Find SU Items with a Given String The doc database located in CWPROOT src doc may also be searched for specific strings or topics The shell script sufind serves this purpose If you type sufind with no options you will see sufind sufind get
125. n the programs segyread and segywrite there are swap flags that permit the user to specify whether the platform they are working on are big endian or little endian platforms In older releases of SU there were problems with the bitwise operations that would be encountered in the wiggle trace drawing routines However these problems have been fixed via the ENDIANFLAG that appears in Makefile config Question 15 How do I convert data that are in the SEG 2 format to SEGY Answer 15 In CWPROOT src Third_Party seg2segy there are two programs that have been made available to us by the University of Pau in France for this purpose These should be easy to install on any system where SU has been installed Once you have converted data seg2 to data segy you may read it into the SU format via segyread tape data segy gt data su 9 3 Tape reading and writing This section contains frequently asked questions about reading and writing SEG Y tapes with SU Tape reading writing is more of an art than a science Here are a few tips 1 Make sure your tape drive is set to be variable block length If you are on an IBM RS6000 this means you will need to use smit to set blocksize 0 on your tape device Having the tape drive set to some default constant blocksize say blocksize 1024 or 512 will foil all attempts to read an SEG Y tape 90 CHAPTER 9 ANSWERS TO FREQUENTLY ASKED QUESTIONS 2 To read multiple tape files on a tape use th
126. nce Note that the filenames must appear before the op 5 1 Transform and Filtering Operations A major aspect of seismic research and seismic processing is related to operations which are based on mathematical transform methods In particular much of seismic processing would not exist without numerical Fourier transforms Filtering is a related subject because the majority of filters are applied in the frequency domain or are at least representable mathematically as frequency domain operations In addition to standard Fourier transforms there are a couple of other transforms such as the Hilbert transform and the Gabor transform which are also included in the SU package These items may find more use as educational tools rather than processing tools 5 1 1 Fourier Transform Operations There are Fourier transform operations for both 1D and 2D applications in the SU package The 1D transforms provide spectral either amplitude or phase information about each trace in a panel of seismic data The 2D transforms include the seismic F K variety assuming that the fast dimension of the input data is temporal and the second dimension is spatial and the non seismic K1 K2 variety in which the input is assumed to be purely spatial x1 x2 data 5 1 2 1D Fourier Transforms e SUFFT fft real time traces to complex frequency traces e SUIFFT fft complex frequency traces to real time traces e SUAMP output amp phase real or imag t
127. nd expandibility The fundamental Unix philosophy is that all operating system commands are programs run under that operating system The idea is that individual tasks be identified and that small programs be written to do those tasks and those tasks alone The commands may have options that permit variations on those tasks but the fundamental idea is one program one task Because Unix is a multi tasking operating system multiple processes may be strung together in a cascade via pipes This decentralization has the advantage of minimizing overhead by not launching single monster applications that try to do everything as is seen in Microsoft applications or in some commercial seismic utilities for example Unix has the added feature of supporting a variety of shell languages making Unix itself a meta language Seismic Unix benefits from all of these attributes as well In combination with standard Unix programs Seismic Unix programs may be used in shell scripts to extend the functionality of the package Of course it may be that no Unix or Seismic Unix program will fulfill a specific task This means that new code has to be written The availability of a standard set of source code designed to be readable by human beings can expedite the process of extending the package through the addition of new source code 1 2 What SU is not The SU package is not a graphical user interface driven utility at this time though there a
128. ngth 58 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT Chapter 5 General Operations on SU Data Beyond the task of editing SU data are operations level codes which perform e gaining e resampling e unary operations arithmetic operations involving a single data file e binary operations arithmetic operations involving two data files The purpose of this section therefore will be to discuss the programs e SUADDNOISE add noise to traces e SUGAIN apply various types of gain to display traces e SUOP do unary arithmetic operation on segys e SUOP2 do a binary operation on two data sets that perform these operations 5 0 7 SUADDNOISE Add noise to SU data While it may seem that having a program that adds noise to seismic data is counterproductive it is often useful for testing purposes to have the capability of simulating noise It is also useful for demonstration purposes and many of the demos below use suaddnoise to fill in the blanks in the suplane testpattern A couple of examples of the output of this program using suplane data suplane suxwigb title no noise Y suplane suaddnoise suxwigb title noise added amp suplane suaddnoise sn 2 suxwigb title noise added amp 5 0 8 SUGAIN Gaining to SU data There are numerous operations which come under the heading of gaining which sugain performs These operations include e scaling the data e multiplying the data by a p
129. non seismic data float d2 sample spacing between traces float 2 first trace location float ungpow negative of power used for dynamic range compression float unscale reciprocal of scaling factor to normalize range int ntr number of traces short mark mark selected traces short shortpad alignment padding short unass 14 unassigned NOTE last entry causes a break in the word alignment if we REALLY want to maintain 240 bytes the following entry should be an odd number of short UINT2 OR do the insertion above the mark keyword entry float data SU_NFLTS segy HELP FACILILTIES B 4 SUKEYWORD LIST THE SU DATATYPE SEGY KEYWORDS 133 typedef struct 1 bhed binary header int jobid job identification number int lino line number only one line per reel int reno reel number short ntrpr number of data traces per record short nart unsigned short hdt unsigned short dto unsigned short hns unsigned short nso number of auxiliary traces per record sample interval in micro secs for this reel same for original field recording number of samples per trace for this reel same for original field recording short format data sample format code 1 floating point 4 bytes 2 fixed point 4 bytes 3 fixed point 2 bytes 4 fixed point w gain code 4 bytes short fold CD
130. note on your terminal window there will be a message with clip some number for example xwigb clip 1 This indicates the amplitude value above which traces are clipped You may think of this as the value of the maximum on the trace 5 0 9 SUOP Unary Arithmetic Operations on SU Data Occassionally we want to apply mathematical functions or other operations which go beyond gaining to data Such operations might include e absolute value e signed square root e square e signed square e signum function e exponential e natural logarithm e signed common logarithm e cosine 61 e sine e tangent e hyperbolic cosine e hyperbolic sine e hyperbolic tangent e divide trace by Max Value e express trace values in decibels 20 slog10 data e negate values e pass only positive values e pass only negative values Operations involving logarithms are punctuated meaning that if the contains 0 values 0 values are returned Examples of suop using SU plane data may be easily run suplane suaddnoise gt data su suop lt data su op abs suxwigb title absolute value amp suop lt data su op ssqrt suxwigb title signed square root amp suop lt data su op sqr suxwigb title signed square amp Please type suop to see the selfdoc and the other options 5 0 10 SUOP2 Binary Operations with SU data To perform operations two SU datasets the progam
131. ns 4 2 1 PSBBOX Changing the BoundingBox For example create test PostScript data with suplane and supswigb via suplane supswigb gt junk1 eps where the eps extension is chosen as a reminder that this is encapsulated PostScript Let s say that there is too much white space surrounding this figure To fix this problem we want to change the size of the BoundingBox at the top of the file For example more junki eps 4 2 ADDITIONAL POSTSCRIPT SUPPORT 49 shows the dimensions of the BoundingBox 4 PS Adobe 2 0 EPSF 1 2 7 DocumentFonts BoundingBox 13 31 603 746 We could manually edit this but with psbbox we can type psbbox lt junk1 eps 11x 40 11y 80 urx 590 ury 730 gt junk2 eps Original BoundingBox 13 31 603 746 Updated BoundingBox 40 80 590 730 to yield a smaller BoundingBox with correspondingly less white space 4 2 2 PSMERGE MERGE2 MERGE4 Merging PostScript Plots It is often useful to merge several plots to make a compound figure The program psmerge is the general tool in SU provided for this There are two additions shell scripts which call psmerge called merge2 and merge4 If we make a couple of test datasets suplane gt junk su suplane sufilter gt junk1 su and display these by various means supswigb lt junk su title Wiggle trace label1 sec label2 trace number gt junk1 eps supsimage lt junk su title Image Plot labeli sec label2 trace number g
132. ns suggestions regarding SU or if you have your own SU style programs to contribute to the package 18 CHAPTER 2 HELP FACILITIES Chapter 3 Core Seismic Unix Programs The core of the Seismic Unix program set performs a broad collection of tasks which may be viewed as being common to a large collection of research and processing disciplines Many however are purely seismic in nature and are indicated as such in the text Some of these tasks include e input output issues e data format conversion e setting viewing and editing trace header fields viewing SU data e windowing sorting and editing the data general operations e transform and filtering operations e seismic operations on SU data It is the intent of the chapters that follow is to deal with many of these issues Please note that more detailed information about any of the programs discussed can be obtained by typing the name of the program on the commandline with no arguments programname or by typing sudoc programname to see the selfdoc information This chapter does not cover all SU programs but just a sufficient number such that a person with some Unix experience can get started with the package Once you get the idea of how SU is used then you may draw on the help facilities to discover additional programs in the package 19 20 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS 3 1 Reading and Writing Data to and from Tapes Reading tapes is
133. nsional matrices that are too big BUTTERWORTH Functions to design and apply Butterworth filters COMPLEX Functions to manipulate complex numbers COMPLEXD Functions to manipulate double precision complex numbers COMPLEXF Subroutines to perform operations on complex numbers CONVOLUTION Compute z x convolved with y CUBICSPLINE Functions to compute CUBIC SPLINE interpolation coefficients DBLAS Double precision Basic Linear Algebra subroutines DGE Double precision Gaussian Elimination matrix subroutines adapted PFAFFT Functions to perform Prime Factor PFA FFT s in place FRANNOR functions to generate a pseudo random float normally distributed FRANUNI Functions to generate a pseudo random float uniformly distributed HANKEL Functions to compute discrete Hankel transforms HILBERT Compute Hilbert transform y of x B 2 SUNAME 119 HOLBERG1D Compute coefficients of Holberg s ist derivative filter IBMFLT_ Convert IBM tape format to floats and back INTCUB evaluate y x y x y x via piecewise cubic interpolation INTL2B bilinear interpolation of a 2 D array of bytes INTLIN evaluate y x via linear interpolation of y x 0 y x 1 INTSINC8 Functions to interpolate uniformly sampled data via 8 coeff sinc INTTABLE8 Interpolation of a uniformly sampled complex function y x MKDIFF Make an n th order DIFFerentiator via Taylor s series method MKHDIFF Compute filter approximating the ban
134. ntent is that plots of the output should appear correct when compared with a plot of the original data The effect of the 2D Fourier transform on a line of spikes is to produce a line of spikes normal to the original line if the k1 k2 data are plotted on the same plot as the x1 x2 data 5 2 Hilbert Transform Trace Attributes and Time Frequency Domain A number of classical techniques for representing instantaneous trace attributes have been created over the years Many of these techniques involve the construction of a quadrature trace to be used as the imaginary part of a complex trace with the real part being the real data The quadrature trace is created with the Hilbert transform following the construction of the so called allied function This representation permits instantaneous amplitude phase and frequency information to be generated for a dataset by taking the modulus phase and time derivative of the phase respectively An alternate approach is to perform multi filter analysis on data to represent it as a function of both time and frequency Tools in SU which perform these operations are e SUHILB Hilbert transform e SUATTRIBUTES trace ATTRIBUTES instantanteous amplitude phase or frequency e SUGABOR Outputs a time frequency representation of seismic data via the Gabor transform like multifilter analysis To generate the Hilbert transform of a test dataset try suplane suhilb suxwigb title Hi
135. nts of the form of bcopy a b c with a statements of the form memcpy void b const void a c 9 2 Data format questions In this section we address questions about converting data that are in various formats into SU format Question 5 What is the data format that SU programs expect Answer 5 The SU data format is based on but is not exactly the same as the SEG Y format The SU format consists of data traces each of which has a header The SU trace header is identical to SEG Y trace header Both the header and the trace data are written in the native binary format of your machine You will need to use segyread to convert SEGY data to SU data Caution The optional fields in the SEG Y trace header are used for different purposes at different sites SU itself makes use of certain of these fields Thus you may need to use segyclean see the answer to Question 7 SU format does not have the binary and ebcdic tape headers that are part of the SEG Y format After installing the package you can get more information on the SEG Y SU header by typing sukeyword o This lists the include file segy h that defines the SU trace header Question 6 Is there any easy way of adding necessary SEG Y information to our own modeled data to prepare our data for processing using the SU package Answer 6 It depends on the details of how your data was written to the file 1 If you have a datafile that is in the form of binary floating
136. o scripts I get many error messages describing programs that the shell script cannot find How do I fix this Answer 11 You need to put CWPROOT bin where CWPROOT is your root path that contains the CWP SU source code include files libraries and executables in your shell PATH This is done in your cshrc file if you run under csh or tcsh In Bourne shell sh Born Again shell bash or Korn shell ksh the PATH variable is in your profile file You also need to type rehash if you are running C shell bin csh or TC shell bin tcsh as your working shell environment if you have not relogged since you compiled the codes Question 12 How do I transfer data between SU and a commercial package such as Promaz Answer 12 The short answer is that you make a SEGY tape on disk file To do convert a file called say data su to a segy file do the following segyhdrs lt data su segywrite tape data segy lt data su Now use Promax to read data segy This file is a Promax tape on disk file in IBM Real format Choose Promax menus accordingly For other commercial packages use the appropriate commands to read a SEGY tape on disk file To go from the commercial package to SU follow the reverse steps Create a file that is a SEGY tape image and then use segyread tape data segy segyclean gt data su 9 3 TAPE READING AND WRITING 89 Question 13 I would like to strip the trace headers off of some SU data perform an ope
137. of the polygon defined by the vector of frequency values defined by array of f values and a collection of amplitude values defined by the array of amps values The amplitudes may be any floating point numbers greater than or equal to zero The only rule is that there must be the same number of amps values as f values The segments are sine squared tapered between f values of different amplitude It is best to select bf f values such that tapering to zero is done over an octave to prevent ringing With suplane sufilter provides a way of easily generating bandlimited testpattern data in SU format 5 4 2 SUBFILT apply Butterworth bandpass filter An alternative to sufilter is subfilt which applies a Butterworth filter to data suplane subfilt fstoplo 10 fpasslo 20 fpasshi 30 fstophi 60 suxwigb title 10 20 30 60 hz subsection SUACOR auto correlation This program is used to compute the autocorrelation of a trace This process is useful to see the size of a wavelet or the repetitions of the wavelet as an aid in choosing the bf maxlag parameter of bf supef bf Suacor is also useful for determining the frequency range of data in terms of the power spectrum For example try small begin verbatim suplane sufilter suacor suspecfx suxwigb amp be 5 4 1D FILTERING OPERATIONS 67 5 4 3 SUCONV SUXCOR convolution correlation with a user supplied filter The standard operations of convolution an
138. ograms There is also a code to create Gaussian beam synthetic seismograms in a triangulated medium These programs are e NORMRAY dynamic ray tracing for normal incidence rays in a sloth model e TRIRAY dynamic RAY tracing for a TRlangulated sloth model e GBBEAM Gaussian beam synthetic seismograms for a sloth model e TRISEIS Synthetic seismograms for a sloth model There is a comprehensive set of demos located in the directory CWPROOT src Delaunay Triangulation 6 5 Tetrahedral Methods Some new functionality will be entering SU in future releases for tetrahedral model building and ray tracing in tetrahedral models One code that is in the current release is e TETRAMOD TETRAhedron MODel builder In each layer velocity gradient is constant or a 2 D grid horizons could be a uniform grid and or added by a 2 D grid specified 72 CHAPTER 6 SEISMIC MODELING UTILITIES Chapter 7 Seismic Processing Utilities There are a collection of operations which are uniquely seismic in nature representing operations which are designed to perform some aspect of the involved process which takes seismic data and converts it into images of the earth 7 1 7 2 stacking data picking data velocity analysis normal moveout correction dip moveout correction seismic migration and related operations SUSTACK SURECIP SUDIVSTACK Stacking Data SUSTACK stack adjacent traces having the same key header word SURECIP sum oppos
139. om first trace return EXIT_SUCCESS 16 fvgettr code goes here Now we run into a small difficulty Our only parameter has a default value that is obtained only after we read in the first trace The obvious solution is to reverse the parameter getting and the trace getting in the template Thus we resume 102 CHAPTER 10 HOW TO WRITE AN SU PROGRAM Get info from first trace and set ns if fvgettr stdin amp tr err can t get first trace if getparint ns amp ns ns tr ns Loop over the traces do int nt tr ns Now comes the actual seismic algorithm which is rather trivial in the present case add zeroes to the end of the input trace if the output length is specified greater than the input length We could write a simple loop to do the job but the task is done most succinctly by using the ANSI C routine memset However we confess that unless we ve used it recently we usually forget how to use this routine One solution is to cd to the su main directory and use grep to find other uses of memset When we did this we found that sumute had usage closest to what we needed and that is why we started from a copy of that code Here is the complete main for suvlength SUVLENGTH Revision 1 20 Date 2002 08 22 20 19 54 include su h include segy h DOC O COO kkk self documentation JOR KKK char sdoc 4 SUVLENGTH Adjust variable length traces to common length wy
140. on selected trace VALPKGE routines to handle variables of type Value In CWPROOT src psplot lib BASIC Basic C function interface to PostScript PSAXESBOX Functions to draw PostScript axes and estimate bounding box PSAXESBOX3 Functions draw an axes box via PostScript estimate bounding box PSCAXESBOX Draw an axes box for cube via PostScript PSCONTOUR draw contour of a two dimensional array via PostScript PSDRAWCURVE Functions to draw a curve from a set of points PSLEGENDBOX Functions to draw PostScript axes and estimate bounding box PSWIGGLE draw wiggle trace with optional area fill via PostScript In CWPROOT src xplot lib AXESBOX Functions to draw axes in X windows graphics COLORMAP Functions to manipulate X colormaps DRAWCURVE Functions to draw a curve from a set of points IMAGE Function for making the image in an X windows image plot LEGENDBOX draw a labeled axes box for a legend i e colorscale RUBBERBOX Function to draw a rubberband box in X windows plots WINDOW Function to create a window in X windows graphics XCONTOUR draw contour of a two dimensional array via X vectorplot calls In CWPROOT src Xtcwp lib AXES the Axes Widget COLORMAP Functions to manipulate X colormaps FX Functions to support floating point coordinates in X MISC Miscellaneous X Toolkit functions RESCONV general purpose resource type converters RUBBERBOX Function to draw a rubberband box in X windows plot
141. onal parameters Required parameters none Optional parameters key cdp header key word to stack on normpow 1 0 each sample is divided by the normpow th number of non zero values stacked normpow 0 selects no division verbose 0 verbose 1 echos information Note The offset field is set to zero on the output traces Sushw can be used afterwards if this is not acceptable The first line indicates the name of the program sustack and a short description of what the program does This is the same line that appears for the listing of sustack in the suname listing The second line 8 CHAPTER 2 HELP FACILITIES sustack lt stdin gt stdin Optional parameters indicates how the program is to be typed on the commandline with the words stdin and stdout indicating that the input is from the standard input and standard output respectively What this means in Unix terms is that the user could be inputting and outputting data via diskfiles or the Unix redirect in lt and redirect out gt symbols or via pipes The paragraphs labeled by Required parameters and Optional parameters indicate the commandline parameters which are required for the operation of the program and those which are optional The default values of the Optional parameters are given via the equality are the values that the program assumes for these parameters when data are supplied with no additional commandline arguments given For exam
142. opriate However the user may view 24 to be 2 4 We may adopt this convention in the future Remark In the early days we did use RCS to simultaneously update all the codes to 2 1 3 1 This practice died a natural death somewhere along the way Question 22 How often are the codes updated Answer 22 The CWP SU package is updated at roughly 3 6 month intervals We mail announcements of these releases to all known users Since we do not provide support for outdated versions we urge you to remain current Question 23 I have a complicated collection of input parameters for a CWP SU program I want to run the command from the command line of a terminal window but I don t want to retype the entire string of input parameters What do I do Answer 23 CWP SU programs that take their input parameters from the command line also have the feature of being able to read from a parameter file This is invoked by setting the parameter par parfile where parfile is a file containing the desired commandline string For example suplane ntr 20 nt 40 dt 001 is completely equivalent to the command suplane par parfile if the string ntr 20 nt 40 dt 001 is contained in parfile Question 24 I can t find an sudoc entry for the function ints8r yet the SU manual says that all library functions have online documentation What am I doing wrong Answer 24 The proper search procedure for a library function such as ints8r is
143. ower of time e taking the power of the data 59 60 CHAPTER 5 GENERAL OPERATIONS ON SU DATA e automatic gain control e trapping noise spiked traces e clipping specified amplitudes or quantiles e balancing traces by quantile clip rms value or mean e scaling the data e biasing or debiasing the data The heirarchy of the operations is stated by the following equation out t scale BAL CLIP AGC t tpow explepow t in t bias gpow You may see what sugain does by running the following examples using suplane data Noise has been added with suaddnoise to make the affects of AGC apparent Type only the items following the percent Create some SU data with noise added via suplane suaddnoise gt data su suxwigb lt data su title Ungained Data amp sugain lt data su scale 5 0 suxwigb title Scaled data amp sugain lt data su agc 1 wagc 01 suxwigb title AGC 1 WAGC 01 sec amp 8 8 8 g sugain lt data su agc 1 wagc 2 suxwigb title AGC 1 WAGC 1 sec amp 8 8 8 g sugain lt data su pbal 1 suxwigb title traces balanced by rms amp sugain lt data su qbal 1 suxwigb title traces balanced by quantile amp sugain lt data su mbal 1 suxwigb title traces balanced by mean amp sugain lt data su tpow 2 suxwigb title t squared factor applied amp 8 P 8 q PP sugain lt data su tpow 5 suxwigb title square root t factor applied amp Please
144. percent indicates the modulo function and is division For example if we want to set the sx field of the first 5 traces to 6400 the second 5 traces to 6300 decrementing by 100 for each 5 trace groups sushw lt data su key sx a 6400 c 100 j 5 gt data new su Again piping in suplane data into sushw suplane sushw key sx a 6400 c 100 j 5 sugethw key sx more sx 6400 sx 6400 sx 6400 sx 6400 sx 6400 sx 6300 sx 6300 sx 6300 sx 6300 sx 6300 sx 6200 sx 6200 As another example if we wanted set the offset fields of each group of 5 traces to 200 400 6400 sushw lt data su key offset a 200 b 200 j 5 gt data out su As before piping suplane data into sushw yields the following suplane sushw key offset a 200 b 200 j 5 sugethw key offset more offset 200 offset 400 offset 600 offset 800 offset 1000 offset 200 38 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS offset 400 offset 600 offset 800 offset 1000 offset 200 We can perform all 3 operations with one call to sushw via sushw lt data su key dt sx offset a 2000 6400 200 b 0 0 200 c 0 100 0 j 0 5 5 gt newdata su Or with suplane data piped in suplane sushw key dt sx offset a 2000 6400 200 b 0 0 200 c 0 100 0 j 0 5 5 sugethw key dt sx offset more dt 2000 sx 6400 offset 200 dt 2000 sx 6400 offset 400 dt 2000 sx 6400 offset 600 dt 2000 sx 6400 of set 800 dt 2000 sx 6400 offset 1000 dt 2000 sx 6300 offset 200 dt 2000
145. ple key cdp indicates that sustack will stack over the common depth point gather number field cdp The shell script sukeyword tells the choices of keyword that are available 2 4 SUDOC List the Full Online Documentation of any Item in SU As has been alluded to in previous sections of this manual there is a database of selfdocumen tation items that is available for each main program shell script and library function This database exists in the directory CWPROOT src doc and is composed of all of the selfdocu mentation paragraphs of all of the items in SU Because not all all items with selfdocs are executable an additional mechanism is nec essary to see the selfdoc for these items For example information about the Abel trans form routines located in CWPROOT src cwp lib abel c on the system at CWP CWP ROOT usr local cwp is obtained via sudoc abel In usr local cwp src cwp lib ABEL Functions to compute the discrete ABEL transform abelalloc allocate and return a pointer to an Abel transformer abelfree free an Abel transformer abel compute the Abel transform Function prototypes void abelalloc int n void abelfree void at void abel void at float f float g Input ns number of samples in the data to be transformed f array of floats the function being transformed Output at pointer to Abel transformer returned by abelalloc int n gl array of floats the transformed data retu
146. power optional parameters lt indata gt outdata SUIFFT fft complex frequency traces to real time traces suiftt lt stdin gt sdout sign 1 SUMIGPS MIGration by Phase Shift with turning rays sumigps lt stdin gt stdout optional parms SUMIGTK MIGration via T K domain method for common midpoint stacked data sumigtk lt stdin gt stdout dxcdp optional parms SURADON forward generalized Radon transform from x t gt p tau space suradon lt stdin gt stdout Optional Parameters 2 5 SUFIND FIND SU ITEMS WITH A GIVEN STRING 13 For more information type program_name lt CR gt The final line of this output ends with a symbol meant to indicate that the user is to type a carriage return As you can see there is a mixed collection of programs which are either demos of the CWP SU prime factor fft routines pfafft libraries containing the routines or programs that use fft routines 2 5 1 Getting information about SU programs A more specific example would be to use sufind to look for dip moveout DMO programs sufind dmo SUDMOFK DMO via F K domain log stretch method for common offset gathers sudmofk lt stdin gt stdout cdpmin cdpmax dxcdp noffmix SUDMOTX DMO via T X domain Kirchhoff method for common offset gathers sudmotx lt stdin gt stdout cdpmin cdpmax dxcdp noffmix optional parms SUDMOVZ DMO for V Z media for common offset gathers sudmovz lt stdin gt stdout cdpmin
147. prediction error filtering method also known as Wiener filtering is the principle process of tradi tional Wiener Levinson deconvolution The reason that this subsection is not headed deconvolution is because there are two additional issues that have to be addressed before prediction error filtering can be used for effective deconvolution These issues are preprocessing of the data and postprocess filtering Indeed much feedback has come back claiming that supef doesn t work properly when in fact it simply being used improperly This is our fault for not supplying sufficient documentation Using supef itself generally requires that the value of maxlag be set This may be determined by first establishing the size of the wavelet being spiked through application suacor As the preprocessing step you will probably need to use sugain to remove any decay in amplitudes with time that may result from geometric spreading As a postprocessing step you need to remove any increase in frequency content which has occurred due to the whitening effect of the prediction error filter The demos in the demos Deconvolution directory demonstrate the functioning of the program However these examples are a bit unrealistic for field data For example in the demos the data are spiked and then reverberations are removed via a cascaded of supef calls with maxlag 04 and minlag 05 maxlag 16 respectively However on field data we would probably only use a
148. priately Convert hdrfile to a binary format via a2b lt hdrfile ni nfields gt binary_file were nfields is the number of header fields in the key list above Then load the new file of header fields via sushw lt sudata infile binary_file key key1 key2 gt sudata edited Again key key1l key2 here is the same list as in the sugethw statement above The finished product is the file sudata edited If you are just beginning to set the header fields you may build the ASCII header file hdrfile any way you want This could be with your favorite text editor or with a spreadsheet program It is not important how the ascii file is created as long as it is in multi column ASCII format for the sequence above Of course if you have the header values in a file consisting of C style floats which you can make either from a C program or from Fortran data with ftnstrip listed trace by trace then you already have the binary_file and need only execute the final sequence 3 5 8 SUCHW Change or Compute Header Words in SU Data Some header fields such as cdp may be computed from existing header fields The program suchw provides this functionality From the selfdoc of suchw keyl cdp output key s key2 cdp input key s key3 cdp input key s a 0 overall shift s scale on second input key s 0 1 scale s on first input key s 0 1 overall scale s Teen a
149. pter 8 Processing Flows with SU 8 1 SU and UNIX You need not learn a special seismic language to use SU If you know how to use UNIX shell redirecting and pipes you are ready to start using SU the seismic commands and options can be used just as you would use the built in UNIX commands In particular you can write ordinary UNIX shell scripts to combine frequent command combinations into meta commands i e processing flows These scripts can be thought of as job files Table 8 1 UNIX Symbols processl lt filel processl takes input from filel process2 gt file2 process2 writes on new file2 process3 gt gt file3 process3 appends to file3 process4 process output of process4 is input to process5 process6 lt lt text take input from following lines So let s begin with a capsule review of the basic UNIX operators as summarized in Table 8 1 The symbols lt gt and gt gt are known as redirection operators since they redirect input and output into or out of the command i e process The symbol is called a pipe since we can picture data flowing from one process to another through the pipe Here is a simple SU pipeline with input indata and output outdata sufilter f 4 8 42 54 lt indata sugain tpow 2 0 gt outdata This example shows a band limiting operation being piped into a gaining operation The input data set indata is directed into the program sufilter w
150. r fields bytes 181 240 in the SEGY trace headers There is no standard for what may go in these fields so many people have items that they place in these fields for their own purposes SU is no exception There are several parameters used by SU 22 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS graphics programs that may be stored in these fields The program segyclean zeros out the values of the optional header fields so that SU graphics programs don t become confused by this information There are additional issues such as whether or not your device is buffered or unbufferd i e 9 track 1 2 reel tape or 8mm Exabyte tape which may have to be experimented with when you actually try to read a tape Also if you are trying to read a tape on a different system than the one it was made on you may simply not be able to read the tape The most common problem with reading tapes is matching the density that the tape was written in with the tapedrive that the tape is being read on Some systems for example Silicon Graphics SGI systems have many tape devices which support different hardware configurations and tape densities Other systems most notably recent versions of Linux have an improved version of the Unix command mt which has a setdensities option In either case it is common for tapes to be made using the default settings of a tape drive or its default densities As a last resort in all tape reading situations it is often possible to
151. race from frequency x e SUSPECEX Fourier SPECtrum T to F of traces domain data 5 1 TRANSFORM AND FILTERING OPERATIONS 63 The program sufft produces the output of the Fourier transform operation as a complex data type The program suifft is designed to accept complex input as would be generated by sufft to perform the inverse Fourier transform The cascade of these operations is not quite an non operation because there is zeropadding which is automatically implemented for the transforms Also the header fields will not quite be right for seismic data For example try suplane suxwigb title 0riginal Data amp suplane sufft suifft sushw key d1 dt a 0 4000 suxwigb amp The result is the same as the input except there are more samples on the traces due to zero padding required for the transform To view the amplitude and phase spectra and the real and imaginary parts of the of the output of sufft do the following suamp mode amp suxwigb title amplitude amp suamp mode phase suxwigb title phases amp suamp mode real suxwigb title real amp suamp mode imag suxwigb title imaginary amp suplane sufft suplane sufft suplane sufft suplane sufft SU data has a format which allows for the storage of the real and imaginary parts of data in a complex datatype To see the header field settings for that format type suplane sufft surange sufft d1 3 571
152. rameters dt from header time sampling interval sec fmin 0 minimum frequency of filter array hz fmax NYQUIST maximum frequency of filter array hz beta 3 0 In filter peak amp filter endpoint amp band 05 NYQUIST filter bandwidth hz alpha beta band 2 filter width parameter verbose 0 1 supply additional info Notes This program produces a muiltifilter as opposed to moving window representation of the instantaneous amplitude of seismic data in the time frequency domain With Gaussian filters moving window and multi filter analysis can be shown to be equivalent An input trace is passed through a collection of Gaussian filters 10 CHAPTER 2 HELP FACILITIES to produce a collection of traces each representing a discrete frequency range in the input data For each of these narrow bandwidth traces a quadrature trace is computed via the Hilbert transform Treating the narrow bandwidth trace and its quadrature trace as the real and imaginary parts of a complex trace permits the instantaneous amplitude of each narrow bandwidth trace to be compute The output is thus a representation of instantaneous amplitude as a function of time and frequency Some experimentation with the band parameter may necessary to produce the desired time frequency resolution A good rule of thumb is to run sugabor with the default value for band and view the image If band is too big then the t f plot will consist of stripes parallel to the
153. rams call on the generic plotting programs to do the actual plotting The alternative design was to have tuned graphics programs for various seismic applications Our design choice keeps things simple but it implies a basic limitation in SU s graphical capabilities The plotting programs are the vehicle for presenting your results Therefore you should take the time to carefully look through the self documentation for both the SU jacket programs suximage suxwigb and the generic plotting programs ximage xwigb 78 CHAPTER 8 PROCESSING FLOWS WITH SU 8 2 2 Executing shell programs The simplest way to execute a UNIX shell program is to give it execute permission For example to make our above Plot shell program executable chmod x Plot Then to execute the shell program Plot 601 610 Here we assume that the parameters cdpmin 601 cdpmax 610 are appropriate values for the cmgs data set Figure 8 1 shows an output generated by the Plot shell program Trace number 0 100 200 Time sec CMP Gathers 601 to 610 Figure 8 1 Output of the Plot shell program 8 2 3 A typical SU processing flow Suppose you want to use sudmofk You ve read the self doc but a detailed example is always welcome isn t it The place to look is the directory su examples In this case we are lucky and find the shell program Dmo Again the numbers in square brackets at the end of the lines shown below are not part of the l
154. raphics codes used in the pre workstation i e graphics terminal age of SU Liner s broad knowledge of seismology and seismic processing enabled him to make a positive and continuing influence on the SU coding philosophy Craig Artley now at Golden Geophysical made major contributions to the graphics codes while a student at CWP and continues to make significant contributions to the general package Dave Hale wrote several of the heavy duty processing codes as well as most of the core scientific and graphics libraries His knowledge of good C language coding practice helped make our package an excellent example for applied computer scientists Ken Larner contributed many user interface ideas based on his extensive knowledge of seismic processing in the real world ix x ACKNOWLEDGMENTS John Scales showed how to use SU effectively in the classroom in his electronic text Theory of Seismic Imaging Samizdat Press 1994 This text is available from the Samizdat press site at samizdat mines edu John Stockwell s involvment with SU began in 1989 He is largely responsible for designing the Makefile structure that makes the package easy to install on the majority of Unix platforms He has been the main contact for the project since the first public release of SU in September of 1992 Release 17 After Jack Cohen s death in 1996 Stockwell assumed the role of principal investigator of the SU project and has remained in this capaci
155. ration of some type on the bare traces and put the headers back on without losing any of the header information How do I do this Answer 13 Do the following sustrip lt data su head headers gt data binary Do whatever was desired to data binary to make datal binary supaste lt datal binary head headers gt datal su Question 14 I have made some data on an IBM RS6000 and have transferred it to my Linux based PC system The data looks ok on the RS6000 but when I try to work with it on the PC none of the SU programs seem to work What is wrong Answer 14 The problem you have encountered is that there are two IEEE binary formats called re spectively big endian and little endian or alternately high byte and low byte These terms refer to the order of the bytes that represent the data IBM RS6000 Silicon Graphics NeXT black hardware SUN HP PowerPC any Motorola chip based platforms are big endian machines whereas Intel based PCs and Dec and Dec Alpha products are little endian platforms Two programs are supplied in the CWP SU package for swapping the bytes for data transfer These are swapbytes and suswapbytes The program swapbytes is designed to permit the user to swap the bytes on binary data that are all one type of data floats doubles shorts unsigned shorts longs unsigned longs and ints For data that are in the SU format the program suswapbytes is provided Furthermore withi
156. re the main processing loop starts So far so good But now our plan runs into a serious snag the fundamental trace getting facility gettr itself assumes fixed length traces or perhaps we should say that gettr deliberately enforces the fixed length trace standard But if you think about it you ll realize that gettr itself has to take special measures with the first trace to figure out its length All we have to do is make a new trace getting routine that employs that first trace logic for every trace Here we ll suppress the details of writing the fvgettr subroutine and turn to converting the template above into the new suvlength code SUVLENGTH Revision 1 20 Date 2002 08 22 20 19 54 include su h 10 3 WRITING A NEW PROGRAM SUVLENGTH 101 include segy h op OO RE self documentation bobo aK char sdoc SUVLENGTH Adjust variable length traces to common length My suvlength lt variable_length_traces gt fixed_length_traces Ms Required parameters Mag none A Optional parameters ns output number of samples default 1st trace ns NULL RRR RRR RRR end self COC I I kk Credits CWP Jack Cohen John Stockwell prototype int fvgettr FILE fp segy tp segy tr main int argc char argv int ns number of samples on output traces Initialize initargs argc argv requestdoc 1 Get parameters Get info fr
157. re several possibilities including Java and TCL TK scripts which may be exploited for this purpose in the future Because most commercial seismic processing packages are GUI based it is unavoidable that users will expect SU to be similar to these packages However this is not a fair comparison for several reasons 1 3 OBTAINING AND INSTALLING SU 3 As mentioned above SU is an extension of the Unix operating system Just as there are no GUI driven Unix operating systems that give full access to all of the capabilities of Unix from menus it is not reasonable to expect full access to Seismic Unix through such an interface At most any SU interface will give limited access to the capabilities of the package SU is not a replacement for commercial seismic packages Commercial seismic software packages are industrial strength utilities designed for the express purpose of production level seismic processing If you do commercial level processing and have dedicated or plan to dedicate funds to purchase one or more license of such commercial software then it is unlikely that you will be able to substitute SU for the commercial utility However SU can be an important adjunct to any commercial package you use Where commercial packages are used for production work SU often has found a place as a proto typing package Also if new code needs to be written SU can provide a starting base for new software applications Indeed the availability of seismic
158. rned by abel at f g 2 4 SUDOC LIST THE FULL ONLINE DOCUMENTATION OF ANY ITEM IN SU 9 Notes The Abel transform is defined by Infinity g y 2 Integral dx f x sqrt 1 y x 72 Iyl Linear interpolation is used to define the continuous function f x corresponding to the samples in f The first sample f 0 corresponds to f x 0 and the sampling interval is assumed to be 1 Therefore the input samples correspond to 0 lt x lt n 1 Samples of f x for x gt n 1 are assumed to be zero These conventions imply that glo 0 2 f 1 2 2 2x n 1 References Hansen E W 1985 Fast Hankel transform algorithm IEEE Trans on Acoustics Speech and Signal Processing v ASSP 33 n 3 p 666 671 Beware of several errors in the equations in this paper Authors Dave Hale and Lydia Deng Colorado School of Mines 06 01 90 Here we see that sudoc shows information about the routines including their names usage information via the function prototype some theory of how the items are used published references and finally the author s names As an another example type sugabor SUGABOR Outputs a time frequency representation of seismic data via the Gabor transform like multifilter analysis technique presented by Dziewonski Bloch and Landisman 1969 sugabor lt stdin gt stdout optional parameters Required parameters if dt is not set in header then dt is mandatory Optional pa
159. rsion of 3D datasets Suinvco3d Common offset migration in v z media Finite_Difference traditional Claerbout FD migration Fourier_Finite_Difference Fourier FD migration Gazdag traditional Gazdag phaseshift migration Kirchhoff Kirchhoff migration Sukdmig2d_common_offset Common offset migration Sukdmig2d_common _shot Common shot migration Phase_Shift_Plus_Interpolation PSPI migration Split_Step Split step migration Stolt Stolt migration Suinvvxzco Inversion in v x z media for common offset data sets Sumigpsti Phaseshift Migration in Transversely Isotropic media NMO Traditional Normal Moveout correction Offset_Continuation Offset continuation to smaller offsets Picking Trace Picking Supickamp Automated picking Plotting Plotting demos CurveOnImage Draw a curve on an image plot Refraction Refraction applications GRM Generalized Reciprocal Method for a single layer Residual_Moveout Velocity analysis by residual moveout analysis SUManual Shell scripts used to make plots in the SU User s Manual Plotting Plotting demos x Psmerge Merge PostScript files with psmerge Xmovie Make X windows movies with suxmovie Selecting Traces Selecting traces by header values for specific operations Sorting_Traces Sorting traces with susort Demo Sorting traces demo Tutorial Sorting traces tutorial Statics Static time shift corrections 141 Residual_Refraction_Statics applying residual
160. ry header file 3 1 7 SEGDREAD Other SEG formats 02 3 1 8 DT1TOSU Non SEG tape formats 3 2 Data Format conversion i atreg inian e 3 2 1 A2B and B2A ASCII to Binary Binary to ASCH 3 2 2 FTNSTRIP Importing Fortran DatatoC 3 2 3 Going from C to Fortran o 3 2 4 H2B Importing 8 Bit Hexidecimal 0 3 2 5 RECAST Changing Binary Data Types 3 2 6 TRANSP Transposing Binary Data vi CONTENTS 3 2 7 FARITH Performs simple arithmetic on binary data 29 3 3 Trace Header Manipulation 0 000000 ee ee ee ee 30 3 3 1 SUADDHEAD Adding SU Headers to Binary Data 30 3 3 2 SUSTRIP Strip SU headers SU data 30 3 3 3 SUPASTE Paste SU Headers on to Binary Data 31 3 4 Byte Swapping r en e a A A a A oe ees 31 3 4 1 SWAPBYTES Swap the Bytes of Binary non SU Data 31 3 4 2 SUSWAPBYTES Swap the Bytes of SU Data 31 3 5 Setting Editing and Viewing Trace Header Fields 32 3 5 1 SUADDHEAD add SU SEGY style Trace Headers 33 3 5 2 SUSTRIP and SUPASTE Strip and Paste SU Headers 33 3 5 3 SUKEYWORD See SU Keywords 0 e 33 3 5 4 SURANGE Get the Range of Header Values 34 3 5 5 SUGETHW Get the Values of Header Words in SU Dat
161. s Reminder No spaces or tabs after the line continuation symbol Notice that we broke the nice indentation structure by putting the final END against the left margin That s because the sh manual page says that the termination should contain only the END or whatever you use In fact most versions support indentation We didn t think the added beautification was worth the risk in a shell meant for export Also note that we used be for an integer arithmetic calculation even though integer arithmetic is built into the Bourne shell why learn two arcane rituals when one will do See man expr if you are curious 8 3 EXTENDING SU BY SHELL PROGRAMMING 83 Velocity m s i 500 2000 2500 3000 Time s Figure 8 2 Output of the CvStack shell program 84 CHAPTER 8 PROCESSING FLOWS WITH SU 8 sunull is a program I Jack wrote to create all zero traces to enhance displays of the sort produced by CvStack Actually I had written this program many times but this was the first time I did it on purpose Yes that was an attempt at humor 9 An arcane calculation to get velocity labeling on the trace axis Very impressive I wonder what it means See last item 10 The exit statement is useful because you might want to save some spare parts for future use If so just put them after the exit statement and they won t be executed Figure 8 2 shows an output generated by CvStack Chapter 9 Answers to Frequently Ask
162. s In CWPROOT src Xmcwp lib RADIOBUTTONS convenience functions creating and using radio buttons SAMPLES Motif based Graphics Functions In CWPROOT src tri lib CHECK CHECK triangulated models CIRCUM define CIRCUMcircles for Delaunay triangulation COLINEAR determine if edges or vertecies are COLINEAR in triangulated CREATE create model boundary edge triangles edge face edge vertex add DELETE DELETE vertex model edge or boundary edge from triangulated model DTE Distance to Edge FIXEDGES FIX or unFIX EDGES between verticies INSIDE Is a vertex or point inside a circum circle etc of a triangulated NEAREST NEAREST edge or vertex in triangulated model PROJECT project to edge in triangulated model READWRITE READ or WRITE a triangulated model B 2 SUNAME 121 In CWPROOT src cwputils CPUSEC return cpu time UNIX user time in seconds CPUTIME return cpu time UNIX user time in seconds using ANSI C built ins WALLSEC Functions to time processes WALLTIME Function to show time a process takes to run In CWPROOT src comp dct lib DCTi 1D Discreet Cosine Transform Routines DCT2 2D Discrete Cosine Transform Routines DCTALLOC ALLOCate space for transform tables for 1D DCT GETFILTER GET wavelet FILTER type LCT1 functions used to perform the 1D Local Cosine Transform LCT LPRED Lateral Prediction of Several Plane Waves WAVEPACK1 1D wavelet packet transform WAVEPACK2 2D Wavelet PACKe
163. s For this purpose we have sutaper to taper the edges of the dataset for example here linear taper over 5 traces on each end of the dataset sutaper lt diskfile gt stdout ntaper 5 and suramp to smooth the beginning and or end of traces for the example here ramp up from 0 to tmin 05 seconds and ramp down from tmax 1 15 seconds to the end of the traces suramp lt diskfile tmin 05 tmax 1 15 gt stdout 4 4 4 SUKILL SUZERO SUNULL SUMUTE zeroing out data It is often useful to zero out noisy traces or traces on the edge of a dataset abrupt analog to tapering or to create null traces as separators to be used between successive panels of data in plotting SUKILL zero out traces To zero out a block of traces type sukill lt stdin gt stdout min MIN_TRACE count COUNT where COUNT is the number of traces to be zeroed and MIN_TRACE is the minimum trace number in the block of traces SUNULL Create a Panel of Empty traces It is sometimes necessary to create a panel of zero value traces To create a panel of traces of NTR traces with NT time samples sunull nt NT ntr NTR lt stdin gt stdout min MIN_TRACE count COUNT SUZERO zero out data within a time window To zero out data within a time window use suzero suzero itmin MIN_TIME_SAMPLE itmax MAX_TIME_SAMPLE lt indata su gt outdata su 56 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT SUMUTE Surgically Muting Data The l
164. s Jack first attempt to learn UNIX was derailed for several weeks by making this mistake The main pipeline of this shell code selects a certain set of cmp gathers with suwind gains this subset with sugain and pipes the result into the plotting program suximage As indicated in the Usage comment the cmp range is specified by command line arguments Within the shell program these arguments are referenced as 1 2 i e first argument second argument The lines within the suximage command are continued by the backslash escape character WARNING The line continuation backslash must be the final character on the line an invisible space or tab following the backslash is one of the most common and frustrating bugs in UNIX shell programming The final amp in the shell program puts the plot window into background so we can continue working in our main window This is the X Windows usage the amp should not be used with the analogous PostScript plotting programs e g supsimage For example with supsimage in place of suximage the might be replaced by lpr The SU plotting programs are special their self doc doesn t show all the parameters accepted For example most of the parameters accepted by suximage are actually specified in the self documentation for the generic CWP plotting program ximage This apparent flaw in the self documentation is actually a side effect of a key SU design decision The SU graphics prog
165. s translate 0 0 in junk3 eps translate 0 0 3 7 in junk4 eps translate 3 3 3 7 gt junk5 eps echo You may view the files junkl eps junk3 eps junk4 eps junk5 eps echo with your PostScript Previewer exit 0 In this case the original files were made small to fit within an 8 1 2 by 11 window However psmerge has the capability of scaling plots This is how the merge2 and merged shells work You can examine the texts of these for further information by typing more CWPROOT bin merge2 or more CWPROOT bin merge4 An additional example of merging 3 plots of different sizes is given by the following shell script bin sh shell script for demonstrating PSMERGE make data suplane gt junk su suplane sufilter gt junk1 su make PostScript Plots of data supswigb lt junk su wbox 7 hbox 4 title Wiggle trace labeli sec label2 traces gt junki eps supscontour lt junk su title Contour Plot labeli sec label2 traces gt junk3 eps supswigp lt junk1 su labell sec title Filtered label2 traces gt junk4 eps merge PostScript plots psmerge in junk1 eps translate 0 0 scale 6 6 in junk3 eps scale 4 4 translate 0 0 3 7 in junk4 eps scale 4 4 translate 3 3 3 7 gt junk5 eps echo You may view the files junk1 eps junk3 eps junk4 eps junk5 eps echo with your PostScript Previewer exit 0 In this case the plots are of normal size and are then scaled to fit wi
166. see binary form for full options X window for binary input data Postscript for SU format input data kk XX XX XK XA XX XX XX XX X XX X XX Xx suagc sudivcor sugain sumix sumute suacor suttoz suvibro suvlength dzdv sudivstack surelan Go to top suxcontour suxgraph suximage suxmax sxplot xcontour xgraph ximage supscontour supscube APPENDIX B HELP FACILILTIES sumedian sukfilter sukfrac sulog suilog suradon sureduce suspecfk XX suspecfx suspeck1k2 sutaup sutsq kk XA sunmo supgc suresstat sustack sustatic unglitch suvelan velpert suxmovie suxpicker suxwigb xmovie xpicker xwigb supsmovie NeXT only B 3 SUHELP HTML see binary form for full options Postscript input data for binary Utilities misc Import Export Import Export Migration and Dip Moveout Poststack migration Prestack Poststack migration Prestack migration Dip Moveout XX XX XA XA XX XX XX X supsgraph supsimage psbbox pscontour pscube psgraph psimage f tlab h2b lcmap lprop merge2 merge4 prplot psepsi psmanager psmerge pslabel XK XA XA XA XA XX XX XX XX XA A KF Go to top a2b b2a bhedtopar dtitosu ftnstrip ftnunstrip recast segdread segyclean segyhdrs segyread Go to top sugazmig sumigfd sumigffd sumiggbzo XX Xx X sukdmig2d
167. ses a sophisticated Makefile structure that you may also use when you develop new code You should begin any new code writing project by creating a local directory in your working area You should then copy the Makefile from CWPROOT src su main into that directory and make the following changes Change D L libcwp a L libpar a L libsu a LFLAGS PRELFLAGS L L lsu lpar lcwp 1m POSTLFLAGS to D L libcwp a L libpar a L libsu a B OPTC g LFLAGS PRELFLAGS L L lsu lpar lcwp lm POSTLFLAGS Change PROGS B bhedtopar B dtitosu B segyclean B segyhdrs B segyread to PROGS 97 98 CHAPTER 10 HOW TO WRITE AN SU PROGRAM B yourprogram where the source code of your program is called yourprogram c and resides in this directory You should then be able to simply type make and yourprogram will be compiled As a test you can try copying one of the existing SU programs from CWPROOT src su main into your local working directory modifying the Makefile accordingly and typing make Indeed because all new SU programs may be viewed as beginning as clones of existing SU programs of a similar structure this is perhaps the best way to begin any new coding venture 10 2 A template SU program Although variations are usually needed a template for a typical SU program looks like the program listing below we excerpted lines from the program sumute to build this templa
168. single pass of the filter to remove reverberations or to spike arrivals The prediction error filter has a spectral whitening effect which is likely to put high frequencies in the data that were not there originally These must be filtered out It is a good idea to assume that there is a loss of frequency information and design the parameters for the postprocessing filtering using sufilter to slightly reduce the frequency content from its original values 68 CHAPTER 5 GENERAL OPERATIONS ON SU DATA Also an added feature of the Release 32 version of supef is the mixing parameter which permits the user to apply a weighted moving average to the autocorrelations that are computed as part of the prediction error filter computation This can provide additional stability to the operation 5 4 5 SUSHAPE Wiener shaping filter The demos in demos Deconvolution also contain a demonstration of the Wiener shaping filter sushape 2D Filtering Operations Filtering in the k1 k2 domain and the F K domain is often useful for changing dip information in data The programs e SUKFILTER radially symmetric K domain sin2 tapered polygonal filter e SUK1K2FILTER symmetric box like K domain filter defined by the cartesian product of two sin2 tapered polygonal filters defined in k1 and k2 e SUKFRAC apply FRACtional powers of i k to data with phase shift e SUDIPFILT DIP or better SLOPE Filter in f k domain provide the beginnings of a set
169. stem Obviously you must really be sure that you want to print this document considering its size However it does contain all of the self documentations for all CWP SU programs library routines and shell scripts and may be a useful one to a lab type reference 2 7 Suhelp html Long time SU contributor Dr Christopher L Liner of the University of Tulsa created the following document which may be accessed from the CWP SU web site or from his location 2 7 SUHELP HTML 15 of http www mcs utulsa edu c11 suhelp suhelp html SeismicUn x Version 33 5 April 1999 An HTML Help Browser This is a help browser for the SeismicUn x free software package developed and maintained by the Center for Wave Phenomena at the Colorado School of Mines The SU project is directed at CWP by John Stockwell The author of this help facility is Dr Christopher Liner an alumnus of CWP who is a faculty member in the Department of Geosciences at The University of Tulsa Last updated January 16 1998 o The arrangement below is by funtionality o Clicking on a program name pulls up the selfdoc for that item o Your web browser s Find capability is useful if you have a fragment in mind e g sort or nmo o While programs may logically apply to more than one catagory below each program appears only once 1 Functional Listing 1 Data Compression 2 Editing Sorting and Manipulation 3 Filtering Transforms and Attributes 4 Gain NMO
170. supscube lt junk su title cube plot gt data4 eps supswigb lt junk su title bitmap wiggle trace gt data3 eps supswigp lt junk su title wiggle trace gt data4 eps supsmovie lt junk su title movie gt datab eps supsmax lt junk su title max gt datad eps XN XN XN SSX XS The output files contain Adobe Level 2 Encapsulated PostScript and is compatible with TeX LaTeX and many draw tools You will need to use a PostScript previewer such as GhostScript or Ghostview to view these files on the screen Please note again that programs for which there is a non SU version have selfdoc information which applies to these codes as well 4 2 Additional PostScript Support There are several additional tools for supporting PostScript operations in SU These are e PSBBOX change BoundingBOX of existing PostScript file e PSMERGE MERGE PostScript files e MERGE2 MERGE2 PostScript figures onto one page e MERGE4 MERGE4 figures onto one page e PSLABEL output PostScript file consisting of a single TEXT string on a specified background Use with psmerge to label plots e PSMANAGER printer MANAGER for HP 4MV and HP 5Si Mx Laserjet PostScript printing e PSEPSI add an EPSI formatted preview bitmap to an EPS file The programs psbbox pslabel psmerge merge2 and merge4 are designed to help in con structing figures made from SU style graphics programs and are not guaranteed to work with EPS files generated by other mea
171. sx 6300 offset 400 dt 2000 sx 6300 offset 600 dt 2000 sx 6300 of set 800 dt 2000 sx 6300 offset 1000 dt 2000 sx 6200 offset 200 dt 2000 sx 6200 offset 400 As you can see it is natural to use pipes and redirects to control job flow but this becomes ungainly on a single command line Later in this document we will see how to construct complicated processing sequences in the controlled environment of shell scripts 3 5 7 Setting Geometry Converting Observers Logs to Trace Headers There is an often unpleasant task called setting geometry which must be performed on field data Often a SEGY tape will have only a rudimentary set of header fields set in the data 3 5 SETTING EDITING AND VIEWING TRACE HEADER FIELDS 39 The rest of the information shot location geophone location etc will be supplied in the form of observers logs For setting geometry you may wish to dump a specific collection of header fields of interest into a file read the file into a text editor or spreadsheet program so that you can make changes For example if you have some file sudata which has some header fields set incorrectly or incompletely then the following command sequence illustrates a possible way of working with such data You begin by reading the selected header fields into a file hdrfile sugethw lt sudata output geom key key1 key2 gt hdrfile Now edit the ASCII file hdrfile with any editor setting the fields appro
172. t junk2 eps supscontour lt junk su title Contour Plot labeli sec label2 trace number gt junk3 eps supswigb lt junk1 su title Filtered label1i sec label2 trace number gt junk4 eps we now have 4 PostScript files which can be merged to make new plots Merging 2 plots may be done via merge2 junk1 eps junk2 eps gt junk m2 eps while merging all 4 plots may be done via merge2 junk1 eps junk2 eps junk3 eps junk4 eps gt junk m4 eps Of course neither merge2 nor merge4 are robust enough to handle all plot sizes so you may need to manually merge plots with psmerge Also if you want to overlay plots such as a graph on top of a wiggle trace plot then you will also need to use psmerge Here is an example of creating plots and merging them with psmerge Because the command sequence is ungainly for typing on the commandline it is expressed as a shell script 4 bin sh shell script for demonstrating PSMERGE make data suplane gt junk su suplane sufilter gt junk1 su make PostScript Plots of data supswigb lt junk su wbox 6 hbox 2 5 title Wiggle trace labeli sec label2 traces gt junki eps 50 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT supscontour lt junk su wbox 2 5 hbox 2 5 title Contour Plot labeli sec label2 traces gt junk3 eps supswigp lt junk1 su wbox 2 5 hbox 2 5 title Filtered label2 traces gt junk4 eps merge PostScript plots psmerge in junk1 ep
173. t dimension in the direction of increasing sample number per trace then it is necessary to add headers so that these data may be accessible to other SU programs If the data are SEGY SEGD DT1 or Bison Geometrics data read from a tape or diskfile then the programs segyread segdread dt1tosu or bison2su will have set the trace header values so that the output will be SU data For data read from some other means such as an ASCII dataset by a2b headers have to be added this is done by using suaddhead If our dataset consists of a file of binary C style floats with say 1024 samples per trace then the command sequence suaddhead lt data bin ns 1024 gt data su will yield the SU datafile data su 3 3 2 SUSTRIP Strip SU headers SU data The inverse operation to suaddhead is sustrip Sometimes you will have data with SU headers on it but you may want to export the data to another program that does not understand SU headers The command sequence sustrip lt data su head data headers gt data bin will remove the SU headers and save them in the file data headers 3 4 BYTE SWAPPING 31 3 3 3 SUPASTE Paste SU Headers on to Binary Data Having performed an operation on the binary data we may want to paste the headers back on This is done with supaste The command sequence supaste lt data bin head data headers gt data su will paste the headers contained in data headers back on to the data 3 4 By
174. t don t arise for most applications For any new SU code one should provide an example shell program to show how the new code is to be used Here is such a program for X Windows graphics bin sh Trivial test of suvlength with X Windows graphics WIDTH 700 HEIGHT 900 WIDTHOFF 50 104 CHAPTER 10 HOW TO WRITE AN SU PROGRAM HEIGHTOFF 20 gt tempdata gt vdata suplane gt tempdata default is 32 traces with 64 samples per trace suplane nt 72 gt gt tempdata suvlength lt tempdata ns 84 sushw key tracl a 1 b 1 gt vdata Plot the data suxwigb lt vdata perc 99 title suvlength test label1 Time sec label2 Traces A wbox WIDTH hbox HEIGHT xbox WIDTHOFF ybox HEIGHTOFF Remove comment sign on next line to test the header sugethw lt vdata tracl ns more Appendix A Obtaining and Installing SU The SU package contains seismic processing programs along with libraries of scientific routines graphics routines and routines supporting the SU coding conventions The package is available by anonymous ftp at the site ftp cwp mines edu 138 67 12 4 The directory path is pub cwpcodes The package may also be obtained on the World Wide Web at http www cwp mines edu cwpcodes Take the files 1 README_BEFORE_UNTARRING 2 untar_me_first xx tar Z 3 cwp su all xx tar Z Here the xx denotes the number of the current release An incremental update is also available for updating the previous release yy to t
175. t ns more tracl 1 tracr 1 of set 400 dt 4000 ns 64 tracl 2 tracr 2 offset 400 dt 4000 ns 64 tracl 3 tracr 3 offset 400 dt 4000 ns 64 tracl 4 tracr 4 offset 400 dt 4000 ns 64 tracl 5 tracr 5 offset 400 dt 4000 ns 64 tracl 6 tracr 6 offset 400 dt 4000 ns 64 tracl 7 tracr 7 offset 400 dt 4000 ns 64 There is no requirement regarding the order of the key words specified or the number of keywords as long as at least one is specified If for some reason you need to dump the values in binary format an example again using suplane data suplane sugethw key tracl tracr offset dt ns output binary gt file bin outputs the values sequentially in order of keyword given trace by trace For geometry setting you may want to use a command sequence again illustrated by piping suplane data into sugethw suplane sugethw key tracl tracr offset dt ns output geom gt hdrfile The contents of hdrfile may be viewed via more hdrfile 1 400 4000 64 2 400 4000 64 3 400 4000 64 4 400 4000 64 5 400 4000 64 N gt sUNe where only the first 5 rows of data have been shown 36 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS 3 5 6 SUSHW Set the Header Words in SU Data The program sushw pronounced SU set header word is an all purpose utility for setting the value of seismic trace headers This program permits the user to set one or more trace header words A common use of sushw is to just set a particular field to one value For example
176. t squares technique e SMOOTH2 SMOOTH a uniformly sampled 2d array of data within a user defined window via a damped least squares technique e SMOOTHSD 3D grid velocity SMOOTHing by the damped least squares Please see the selfdoc of each of these programs for further information Also see the demos in CWPROOT src Velocity_Profiles 6 3 Synthetic Data Generators There are a number of programs for generating synthetic seismic and seismic like data in the SU package These are e SUPLANE create common offset data file with up to 3 planes e SUSPIKE make a small spike data set e SUIMP2D generate shot records for a line scatterer embedded in three dimensions using the Born integral equation e SUIMP3D generate inplane shot records for a point scatterer embedded in three dimensions using the Born integral equation e SUFDMOD2 Finite Difference MODeling 2nd order for acoustic wave equation e SUSYNCZ SYNthetic seismograms for piecewise constant V Z function True amplitude pri maries only modeling for 2 5D e SUSYNLV SYNthetic seismograms for Linear Velocity function e SUSYNVXZ SYNthetic seismograms of common offset V X Z media via KirchhofEstyle model ing e SUSYNLVCW SYNthetic seismograms for Linear Velocity function for mode Converted Waves e SUSYNVXZCS SYNthetic seismograms of common shot in V X Z media via Kirchhoff style modeling Of these only sufdmod2 susynvxz and sysnvxzcs requir
177. t transform WAVEPACK1 1D wavelet packet transform WAVETRANS2 2D wavelet transform by tensor product of two 1D transforms In CWPROOT src comp dct libutil BUFFALLOC routines to ALLOCate initialize and free BUFFers HUFFMAN Routines for in memory Huffman coding decoding PENCODING Routines to en decode the quantized integers for lossless QUANT QUANTization routines RLE routines for in memory silence en decoding In CWPROOT src comp dwpt 1d lib WBUFFALLOC routines to allocate initialize and free buffers in wavelet WPC1 routines for compress a single seismic trace using wavelet packets WPC1CODING routines for encoding the integer symbols in 1D WPC wpciQuant quantize WPC1TRANS routines to perform a 1D wavelet packet transform In CWPROOT src comp dwpt 2d lib WPC routines for compress a 2D seismic section using wavelet packets WPCBUFFAL routines to allocate initialize and free buffers WPCCODING Routines for in memory coding of the quantized coeffiecients WPCENDEC Wavelet Packet Coding Encoding and Decoding routines WPCHUFF Routines for in memory Huffman coding decoding WPCPACK2 routine to perform a 2D wavelet packet transform WPCQUANT quantization routines for WPC WPCSILENCE routines for in memory silence en decoding Shells Libs Shells Libs Shells Libs To search on a program name fragment type Suname name_fragment lt CR gt For more information type program_name lt CR gt
178. ta gt cdata This will produce C style floats most of the time The program assumes that each record of fortran data is preceded and followed by an integer listing the size of the record in bytes There have been fortran data types which have had only one or the other of these integer markers but having both a beginning of record BOR and an end of record EOR markers seems to be standard today 3 2 DATA FORMAT CONVERSION 27 3 2 3 Going from C to Fortran It is fairly easy to transport data made with Fortran code to C however it may not be so easy to go the other way On the SGI Power Challenge it is possible to read a file of C floats called infile via open and read statements that look like OPEN 99 file infile form system DO i 1 number READ 99 tempnumber Array i tempnumber END DO CLOSE 99 The statement form system does not work on all machines however as it is likely that this is not standard Fortran The general format command to read in binary is form unformatted This may not work on other systems for example SUN Indeed it may not be generally guar anteed that you can read binary files in Fortran that have been created with a C programs as in SU If you have problems with binary and the input files are not too big you could convert to ASCII using b2a and use formatted 1 0 OPEN 99 file infile DO i 1 number READ 99 tempnumber Array i t
179. te The numbers in square brackets at the end of the lines in the listing are not part of the listing we added them to facilitate discussion of the template The secret to efficient SU coding is finding an existing program similar to the one you want to write If you have trouble locating the right code or codes to clone ask us this can be the toughest part of the job SUMUTE Revision 1 20 Date 2002 08 22 20 19 54 1 include su h 2 include segy h DOC OCR OR RRO RR self documentation eb KE 3 char sdoc SUMUTE m sumute lt stdin gt stdout Required parameters pe none pa n Optional parameters SS n n Hi Trace header fields accessed ns Ms Trace header fields modified none o n NULL De RRR end self doc ebbo o kkk k kk kk Credits CWP Jack Cohen John Stockwell segy tr 4 main int argc char argv 10 2 A TEMPLATE SU PROGRAM 99 int ns number of samples 5 Initialize initargs argc argv 6 requestdoc 1 7 Get parameters if getparint ntaper amp ntaper ntaper 0 8 Get info from first trace if gettr amp tr err can t read first trace 9 if tr dt err dt header field must be set 10 Loop over traces do 11 int nt int tr ns 12 if below 0 13 nmute NINT t tmin dt memset void tr data int
180. te Swapping Even the best of human intentions can be circumvented This is the case with the IEEE floating point data format The implementation of the IEEE standard by chip manufacturers has resulted in two types of commonly encountered data types These are called big endian high byte or little endian low byte types Little endian machines are Intel or Dec based whereas big endian is every other chip manufacturer Transporting data either regular floating point or SU data requires that the bytes be swapped in order for the data to be read Two issues are necessary to address These are the issues of swapping the bytes in e normal floating point data e SU data Two programs are provided to perform these tasks These are e SWAPBYTES SWAP the BYTES of various data types e SUSWAPBYTES SWAP the BYTES in SU data to convert data from big endian 3 4 1 SWAPBYTES Swap the Bytes of Binary non SU Data If you transport binary data data without SU headers between platforms of a different en dian that is to say the IEEE byte order from the one you are working on then you will have to swap the bytes to make use of that data This problem arises because the order of the mantissa and exponent of binary data comes in two different possible order under the IEEE data standard The so called big endian or high byte IEEE format is found on SGI SUN IBM RS6000 and all Motorola chip based systems The little
181. ted However if materials appear to break between releases please contact me John Stockwell by email so that we can fix the problem Instructions for obtaining and installing SU may be found in Appendix A of this manual Remarkably a software package called CYGWIN32 recently released by the GNU project provides enough Unix like functionality so that SU may be ported to Windows NT with no changes to the SU source code or Makefiles CHAPTER 1 ABOUT SU Chapter 2 Help facilities Like the Unix operating system Seismic Unix may be thought of as a language or meta language As with any language a certain amount of vocabulary must be mastered before useful operations may be performed Because the SU contains many programs there must be a dictionary to permit the inevitable questions about vocabulary can be answered It is intended that this manual be the beginning of such a dictionary SU does not have man pages in the same way that Unix does but it does have equiv alent internal documentation mechanisms There is a general level help utilities which give an overview of what is available For information about specific aspects of a particular code the majority of the programs contain a selfdoc a self documentation paragraph which will appear when the name of the program is typed on the commandline with no options In all of the examples that follow the percent sign indicates a Unix commandline prompt an
182. the scientific community He will surely be missed by all who had contact with him in the mathematical geophysical and SU user communities Preface In the 5 years that have elapsed since the first version of this manual was distributed there have been numerous changes in the SU package These changes have been a result of both in house activities here at CWP and equally important to the many contributions of code bug fixes extensions and suggestions from SU users outside of CWP After reviewing these many changes and extensions and after much discussion with members of the worldwide SU user community it has become apparent that a new manual was necessary This new version began in preparation for a short course on SU at the CREWES project at the University of Calgary Many of the items that were in the original manual such as infor mation about obtaining and installing the package have been have been moved to appendices Additional sections describing the core collection of programs have been added The entire manual has been expanded to include more detailed descriptions of the codes The intent is that you will be able to find your way around the package via the help mechanisms that you will learn to run the programs by running the demos and finally will be able to see how to begin writing SU code drawing on the source code of the package xi xii ACKNOWLEDGMENTS Chapter 1 About SU In 1987 Jack K Cohen and Shuki Ronen o
183. thin an 8 1 2 by 11 window 4 3 TRACE PICKING UTILITIES 51 4 3 Trace Picking Utilities For lack of a better location to discuss this is the subject we will now list trace picking utilities The X Windows wiggle trace image and contour plotting programs all have the attribute that by placing the cursor on the point to be picked and typing the letter s the coordinates of the point are saved in memory When the letter q is typed the values are saved in a user specified file mpicks There are two additional programs which are dedicated to picking issues These are e XPICKER X wiggle trace plot of f x1 x2 via Bitmap with PICKing e SUXPICKER X windows WIGele plot PICKER of an SU data set e SUPICKAMP pick amplitudes within user defined and resampled window with xpicker being the non SU data version which suxpicker calls The xpicker suxpicker programs are interactive tools for picking The program supickamp is a simple automated picking program which seeks the largest amplituded within a user specified window See demos in CWPROOT src demos Picking for more information about supickamp 4 4 Editing SU Data Once the data are read in and the headers are set properly then there will often be manipulation and data editing issues to be dealt with It is often necessary to perform tasks of varying so that data may be e windowed e sorted e truncated e tapered e zeroed e ma
184. thin reel int cdp CDP ensemble number int cdpt trace number within CDP ensemble short trid trace identification code 1 seismic data int offset distance from source point to receiver 34 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS int sx X source coordinate int sy Y source coordinate int gx X group coordinate int gy Y group coordinate short counit coordinate units code short delrt delay recording time time in ms between initiation time of energy source and time when recording of data samples begins for deep water work if recording does not start at zero time unsigned short ns number of samples in this trace unsigned short dt sample interval in micro seconds local assignments float d1 sample spacing for non seismic data float f1 first sample location for non seismic data float d2 sample spacing between traces float f2 first trace location It is a good idea to be aware of this collection when using data derived either from modeling programs or from field datasets 3 5 4 SURANGE Get the Range of Header Values A useful piece of information about trace headers is to see the range of values of the headers in a given dataset Typing surange lt data su will return the ranges of all SU header fields that are nonzero For example suplane surange 32 traces tracl 1 32 tracr 1 32 offset 400 ns 64 dt 4
185. to segyread and segdread 3 1 8 DT1TOSU Non SEG tape formats Currently there is only one non SEG tape format that is completely supported in the SU package and two others which are supported through third party codes which have not yet been integrated into the package This is the Sensors amp Software DT1 format via dt1tosu which is a GPR ground penetrating radar format In the CWPROOT src Third_Party directory are two additional non SEG conversion programs these are segytoseres and bison2su Future plans include incorporating each of these codes into the main CWP SU package 3 2 Data Format conversion Often it is necessary to transfer data from other systems or to input data which may be in a variety of formats A number of tools and tricks are available in SU for dealing with these issues The following programs may be useful for such conversion problems e A2B convert ascii floats to binary e B2A convert binary floats to ascii e FTNSTRIP convert Fortran floats to C style floats e FTNUNSTRIP convert C style floats to Fortran style floats e H2B convert 8 bit hexidecimal floats to binary e RECAST RECAST data type convert from one data type to another e TRANSP TRANSPose an n1 by n2 element matrix 26 CHAPTER 3 CORE SEISMIC UNIX PROGRAMS e FARITH File ARITHmetic perform simple arithmetic with binary files e SUADDHEAD put headers on bare traces and set the tracl and ns fields e SUSTRIP remove the
186. ty to the present The project has also has had extensive technical help from the worldwide SU user commu nity Among those who should be singled out for mention are Tony Kocurko at Memorial Uni versity in Newfoundland Toralf Foerster of the Baltic Sea Research Institute in Warnemuende Germany Stewart A Levin John Anderson and Joe Oravetz at Mobil Oil Joe Dellinger at Amoco Matthew Rutty Jens Hartmann Alexander Koek Michelle Miller of the University of Southern California at Chico Berend Scheffers and Guy Drijkoningen Delft Dominique Rous set Pau and Marc Schaming Strasbourg Matt Lamont Curtin University Australia Wenying Cai at the University of Utah Brian Macy of Phillips Petroleum Robert Krueger of Terrasys Torsten Shoenfelder of the University of Koeln Germany Ian Kay of the Geological Survey of Canada Dr Toshiki Watanabe of the University of Kyoto Our apologies in advance for undoubtedly omitting mention of other deserving contributors to SU we promise to include you in future updates of this manual We especially thank Barbara McLenon for her detailed suggestions on the text and also for her excellent design of this document as well as the SU pamphlets and other materials which we distribute at public meetings In Memoriam Dr Jack K Cohen passed away in October 1996 The Seismic Unix package exists owing to his knowledge of seismic processing his creativity and his desire to make a lasting contribution to
187. udmofk sukdmig2d suoldtonew sustatic press return key to continue Delaunay Triangulation Materials gbbeam normray tri2uni trimodel triray triseis uni2tri Tetrahedra Materials sutetraray tetramod X windows GRAPHICS for Delaunay Triangulation sxplot press return key to continue Straight X windows GRAPHICS 1cmap scmap xepsb ximage xpsp lprop xcontour xepsp xpicker xwigb X Toolkit based X windows GRAPHICS xgraph xmovie xrects Motif based X windows GRAPHICS f tlab X windows GRAPHICS for SU segyclean ed SEGY data sets suxcontour suximage suxmovie suxwigb suxgraph suxmax suxpicker PostScript GRAPHICS psbbox pscube psgraph pslabel psmerge pswigb pscontour psepsi psimage psmanager psmovie pswigp PostScript GRAPHICS for SU segyclean ed SEGY data sets supscontour supsgraph supsmax supswigb supscube supsimage supsmovie supswigp press return key to continue B 2 SUNAME 111 Wavelet Packet Compression wpcicomp2 wpciuncomp2 Wavelet Packet Compression wpccompress wpcuncompress 2D Discrete Cosine Transform Compression dctcomp dctuncomp entropy wptcomp wptuncomp wtcomp wtuncomp press return key to continue CWP SHELLS SCRIPTS Grep cwpfind overwrite time_now weekday argv dirtree precedence todays_date why copyright filetype replace usernames zap cpall newcase this_year varlist PAR SHELLS SCRIPTS gendocs updatedoc updatedocall updatehead POSTSCRIPT RELATED SHELLS SCRIPTS merge2 merge4 SU S
188. ut do not have the original binary data that I made the file from How do I do this Answer 26 You have to restore the binary file to make the new color PostScript file Here is how you do it 1 2 Here we are assuming a bit mapped graphic as would be produced by psimage or supsimage Make a backup of your PostScript file edit the PostScript file removing everything but the hexidecimal binary image that makes up the majority of the file Note in the line preceeding the hexidecimal data portion of the file will be a pair of numbers that represents the dimensions of the data You will need these numbers for later steps use h2b to convert the hexidecimal file to binary You will find that the file is flipped from the original input file Use transp to flip the data Note that the nl and n2 values that are used by transp are the dimensions of the input data which are the reverse of the output data The n1 value is not the total number of samples that is returned by h2b instead total no values n1 x n2 You now have a 0 255 representation of your binary data which you should be able to plot again any way you desire This method may be used to convert scanned images to SU format as well with the next step in the procedure to be putting SU headers on the data with suaddhead 96 CHAPTER 9 ANSWERS TO FREQUENTLY ASKED QUESTIONS Chapter 10 How to Write an SU Program 10 1 Setting up the Makefile The CWP SU package u
189. vided that the code is written using only the items that can be guaranteed to come with the general distributions of X Therefore all of our X windows codes are written using straight X calls or with the X Toolkit While coding in such widget sets as Motif is easier in many respects the code that results is not nearly as portable There are often great differences between the implementation of commercial widget sets on various platforms 43 44 CHAPTER 4 VIEWING SU DATA IN X WINDOWS AND POSTSCRIPT 4 1 1 Plotting General Floating Point Data The programs that are used for viewing general floating point data data without SU headers in the X window environment are e XCONTOUR X CONTOUR Plot of f x1 x2 via vector plot call e XIMAGE X IMAGE plot of a uniformly sampled function f x1 x2 e XWIGB X WIGele trace plot of f x1 x2 via Bitmap e XGRAPH X GRAPHer Graphs nli pairs of x y coordinates e XMOVIE image one or more frames of a uniformly sampled function f x1 x2 Try the following Make some binary data by stripping the headers off of some SU data For example suplane sustrip gt data bin ni 64 n2 32 di 0 004000 nt 64 ntr 32 dt 0 004000 ns 64 The items which follow indicate that the dimensions of the data set are nl 64 by n2 32 Now view these data in each of the plotting programs listed above except xgraph via xcontour lt data bin n1 64 n2 32 title contour ximage lt data bin ni 6
190. w SU set header word suchw SU change or compute header word Type the name of each program to see the self documentation of that code In addition to find out what the header field keywords mentioned in these programs are type sukeyword o You may have the information in a variety of forms The most common and least complicated assump tions of that form will be made here 9 4 GEOMETRY SETTING 91 The task requires the following basic steps 1 Get your data into SU format The SU format is not exactly SEGY but it does preserve the SEGY header information If you are starting with SEGY data either on tape or on in the form of a diskfile then you use segyread to read the data into an su file format For tape segyread tape dev rmt0 bfile data 1 header h 1 segyclean gt data su For diskfile segyread tape data segy bfile data 1 header h 1 segyclean gt data su The file data segy is assumed here to be a tape image of segy data You have to be careful because some commercial software will write SEGY like data by mimicking the layout of the SEGY format but this format will not be in the true IBM tape format that SEGY is defined to be In Promax if you write a SEGY file in IBM Real format then this will be true SEGY tape image working on If you have your data in the SU format then you may view the ranges of the SEGY headers headers that are not set will not be shown via surange
191. which y x is output xout array nxout of x values at which y x is output Output yout array nxout of output y x yout 0 y xout 0 etc Notes Because extrapolation of the input function y x is defined by the left and right values yinl and yinr the xout values are not restricted to lie within the range of sample locations defined by nxin dxin and fxin The maximum error for frequiencies less than 0 6 nyquist is less than one percent Author Dave Hale Colorado School of Mines 06 02 89 Question 25 I have written my own SU programs and would like them to appear in the suname and sudoc listings How do I do this Answer 25 Run updatedocall source code located in CWPROOT par shell If you have put this code under a new path then you must add this path to the list of paths in the updatedoc script For the selfdoc information to be captured by the updatedoc script you will need to have the following marker lines at the beginning and end of the selfdoc and additional information portion of the source code of your program Do ee self documentation aaao RRR x Do RR end self doc COCR k k kok k kkk 9 6 GENERAL 95 Be sure to clone these directly out of an existing SU program rather than typing them yourself so that the pattern is the exact one expected by the updatedoc script Question 26 I have a gray scale not color PostScript file made with psimage and would like to convert it to a color PostScript format b

The New SU User`s Manual

Contents

Download Pdf Manuals

Related Search

Related Contents