iGMT: Interactive Mapping of Geoscientific Datasets. User manual
Contents
1. in usr local bin and add two lines like sethigher_version_gmtbins usr local bin setlower_version_gmtbins usr local oldgmt bin to your igmt_siteconfig tcl file that holds all the necessary modifications to get iGMT running in your environment 4 You will also have to modify the location of the large raster datasets either by editing their individual pathnames in igmt_siteconfig tcl or by following our naming convention and changing only the Srasterpath variable which is intended to point to the directory that holds all the individual datasets As mentioned above you can change many of the other default settings of iGMT such as the help ing applications and the pathnames of dataset locations by modifying the corresponding iGMT variables Most of these variables are set in the Tcl program file igmt_configure tcl You can modify settings by searching for the variable or topic in question and replacing the iGMT variable value directly in the igmt_configure tcl file The preferred way however is to create a igmt_siteconfig tcl file and in sert the corresponding line there This file is read by iGMT after the initialization of the variables by means of igmt_config tcl so that all settings will be overwritten by the users preferences By doing things this way it will be easier to install future versions of iGMT since all local modifications such as different data locations don t have to be changed again 5 1 Examples of modifying default2. 0 020 000 00 Datasets handled by iGMT 6 1 Rasterdata 6 2 Polygon data Usage of iGMT 7 1 MenuFile 7 2 Menu Datasets dd Menuibata parameters a ura draha Gs we a da aA Pdi edad dade iG RS Geel ad outed 7 4 MenuMap parameters u ie aur a ee 7 5 Menu Script 7 6 Menu GMT help Examples Conclusion References A Technical details A 1 Organization of the iGMT software 2 2 2 ee B Modifying iGMT 12 12 13 13 14 14 15 15 18 18 20 20 22 1 Copyright and warranty disclaimer HE a aa aa a a ae aE aE a a Ea HE a a aA Ea Ea a a aE E E EE EEE EE E E E E E EAE iGMT Interactive Mapping of Geoscientific Datasets at your option any later version INDEED PLOTTING WHAT YOU THINK YOU AR along with this program see the file the Free Software Foundation Inc 5 Boston MA 02111 1307 USA SE OSE OSH OH OSE SHE SRE SESH SE SHE SESE SHE SHE SESE SESE HE SE SHE SE SESE SHE SHE SHR BEFORE YOU USE iGMT FOR RESEARCH PURPOSES MAKE SURE YOU ARE Copyright C 1998 2005 Thorsten W Becker Alexander Braun This program is free software you can redistribute it and or modify it under the terms of the GNU General Public License as published by the Free Software Foundation either version 2 of the License or This program is distributed in the hope that it will be useful but WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTABILIT
3. Menu File This menu takes care of the main file handling and general input output functions of iGMT The first item CreatePS leads to the identical action as the Mapit button that is e aGMT script is created and executed e if a postscript file was created this is converted into a GIF e the GIF map display underneath the menu bar is updated The next three items allow the user to create a postscript file only or individually display the postscript This might be helpful if you have trouble installing a PS to GIF converter The filenames used for this process default to tmp igmt_SUSER_tmp ps and tmp igmt_SUSER_tmp gif again this can be changed in igmt_configure tcl or igmt_siteconfig tcl SUSER is replaced by the UNIX user name to avoid conflicts with write permissions if more than one user operates iGMT on a single machine If the produced map files are to be kept the user can either copy them to another place by hand or use the following two items in the menu list SavePSfile and SaveGIFfile Load and Save parameters use a file to dump or restore almost all iGMT parameter settings so that a session can be restarted at a later time without having to redo all the fine tuning iGMT comes with four example parameter files example dat that can be loaded to experiment with the software ParameterFormat allows the user to select which version of the iGMT parameter files should be loaded and written to allow backward compatibility d
4. advantage of the built in handling capabilities for various datasets you need to get the data or tell iGMT where it can find it if the data is already around on your system All path names can be changed together with all other global variables in the igmt_configure tcl or a site specific igmt_siteconfig tcl file see sec 5 Furthermore the user has the option to specify one raster grd file and two custom polygon data sets The igmt_configure tcl is commented so it should be easy to find what you are looking for In addition some of the datasets require special converting software We have put some links to datasets on our web page for your convenience 6 1 Raster data Besides pscoast land and sea coverage and shorelines the following raster data files are supported all can be downloaded in one huge package from href http geodynamics usc edu becker ftp igmt 4Man pages and other documentation are available for the GMT commands Therefore the explicit usage will not be explained in this manual Refer e g to the man page function provided by iGMT or to http www soest hawaii edu wessel gmt gmt_doc html data_comp tgz ETOPOS topography The ETOPOS topography bathymetry NOAA 1988 available at http www ngdc noaa gov is supported in combination with the grdraster tool which is as psvelomeca part of the supplementary package that is available together with the GMT main distribution The ETOPOS data set is about 19MB in i2 b
5. amp Sandwell GTOPO30 dataset in full resolution and has the pscoast shoreline data in high resolution superimposed The original map has fascinating detail that might be lost in this reproduction Sea floor age of Miiller et al Example 3 as resp resented by Fig 3 and the files example3 ps and example3 dat shows the North Atlantic region sea floor age data coverage together with plate boundaries Stereographic projection Gravity anomalies from Sandwell and Smith 1997 The last example example4 of Fig 4 shows gravity anomalies in the Indian ocean ATTENTION This example is quite resource hungry and might lead to problems on smaller machines if actually run with the original data set 16 Ao M A 10 9 33 1 47 9 67 7 120 4 131 9 147 7 180 0 Figure 3 Sea floor age version 1 3 of Miiller et al 1997b and plates from DeMets et al 1990 96 108 mGal 60 55 50 45 40 35 30 25 20 15 10 5 0 5 10 15 20 25 30 35 40 45 50 55 60 Figure 4 Free air gravity anomalies in a part of the Indian ocean from Sandwell and Smith 1997 Dom inant features are the Carlsberg Southwest Indian and Southeast Indian ridges the Bengal fan and the Ninety east ridge Resolution was restricted to 10 instead of 2 arc minutes 17 9 Conclusion The iGMT software package was programmed in a modular way Every routine is commented so it should be fairly easy to modify the code and add extensions to the software If you do so t
6. check if the environment variable igmt_root and wish is available at the places iGMT is looking If all is fine wish is invoked with igmt tcl igmt_def gif is the start up screen 20 Tcl files All files with the tcl extension contain the tcl code that runs iGMT igmt tc1 is the main file it contains source commands and builds up some frames igmt_configure tcl has all global variables and the default settings for plotting whereas igmt_init tcl handles the startup sequence The file igmt_menu tcl holds the definition for the main menu line and the procedures found in igmt_datasets tcl igmt_ parameters tcl and igmt_plotting tcl correspond roughly to all possible actions in the individual pull down menus Finally igmt_iomisc tcl contains most of the input output routines and some additional tcl procedures All of these files should be fairly well commented so that we won t go into any detail here igmt_helper_ files These contain small bash scripts that are called by iGMT tcl routines and handle more operating system based processes Most of them could be integrated into the main tcl code but it seemed more transparent for possible porting to other operating systems to keep them external example dat and ps The dat files contain the parameter dump that was created with iGMT after the examples presented in section 8 were produced The postscript files are packed with gzip and correspond to the shrinked figures in this manual and are not
7. included Vector fields Given two user supplied GMT grd files with v and v components of a vector field v iGMT plots this field using grdvector gt You can change the color and width of the vectors via the normal color and linewidth menus for polygon data Additional parameters can be changed under Data parameters Vector field parameters World Stress Map The World Stress Map WSM Project e g Zoback 1992 Miiller et al 2000 Rei necker et al 2003 http www world stress map org compiles stress measurements all over the world We supply a routine that can read the WSM s ASCII format data base Miiller et al 1997a 2000 It plots either only the compressive directions of the horizontal stress regime as it is commonly done or different style vector pairs on basis of the focal mechanism classification for the horizontal plane projection The different vector style plots two equal length vectors one compressional one extensional if the focal mechanism is labeled strike slip one compressional extensional vector if the focal mechanism is purely compressional extensional and it uses one half length and one full length vector for compressional or extensional mechanisms with a strike slip component in the horizontal plane Major cities We have supplied a rather inaccurate data set of 726 cities with their names and locations This data set can be restricted to the major 235 cities The correspond
8. man command looks for them uncomment the line Finally the two buttons on the right hand side of the menu bar do what they say 8 Examples The following examples were produced by running iGMT with the full data sets as described above They can be reproduced if the data is available locally by loading the parameters file given in the distribution Hypocentres from the NEIC dataset Figure 1 shows the map of examplel ps from the iGMT distribu tion the whole Earth in the Mollweide projection ETOPOS in 60 arc minute resolution is the ground raster 15 6000 3000 1000 0 500 1000 5000 Figure 2 A part of the Carlsberg ridge in the Indian Ocean as of example2 ps parameters can be loaded from example2 dat The original file has extremely high resolution and was quite big The reduced image shown here was shrunk to 81dpi using xv Bathymetry data is from Smith and Sandwell 1997 plate boundary from DeMets et al 1990 scale is the same than in Fig 1 layer All hypocentres of the USGS NEIC dataset from 1973 1997 with magnitude greater than five and NUVELI plate boundaries are superimposed Load examplel dat to produce this plot To reduce the size of this documentation the postscript file is not exactly that produced by iGMT but a converted GIF with lower resolution Smith amp Sandwell GTOPO30 topography Figure 2 of example number two shows a part of the Indian ocean and the Indian subcontinent It was produced using the Smith
9. rainbow colored colorscale col 13 cpt use awk fS igmt_root colminmax awkmin 2max 3 ldots Sigmt_root colormaps col 13 cpt gt new_colormap cpt Here means that the above should be in one line Also you might want to use the grd2cpt function of GMT that can be accessed over createcolormap menu item B Modifying iGMT iGMT may be freely modified and distributed as long as modified versions are not called iGMT There are plenty of easy possible future enhancements one could think of for instance interactive design of colormaps support of more complicated user data sets and multiple layers of raster data When this extensions become available they will be included in future versions Some common modification as opposed to extension or enhancement tasks are described below Using other path names for the datasets All pathnames to data locations are assigned in igmt_configure tcl All raster data sets have two variables assigned to them raster_data i and raster_colormap i they refer to the location of the raster data set number i and the location of the default colormap re spectively Simply add a line like setraster_data 3 home user gtopo30 topo_6 2 img to your igmt_siteconfig tcl file if your GTOPO30 dataset number 3 internally is in home user gtopo30 The equivalent variables for polygon data are called poly_data i and it is simplest to search for the appropriated variable names in igmt_configure tcl Inclu
10. the Tk toolkit Ousterhout 1993 are currently available at http www tcltk com or http dev ajubasolutions com Version 8 0 of Tcl Tk was used for develop ing older versions may work as well From the newer releases we found that 8 2 1 gave problems while 8 3 seems to work fine Tcl is available for UNIX PC Mac and other platforms GMT The generic mapping tools Wessel and Smith 1991 1995 1998 do the mapping part they are called by a script file produced from within iGMT The source code distribution of GMT as well as documentation is available at http www soest hawaii edu wessel gmt html GMT itself has some additional software requirements such as the availability of the netcdf library see the GMT documentation iGMT can handle GMT versions 3 4 5 and 4 0 we have included the option to change the binary directories according to the GMT version that is selected To modify these optional directories set the iGMT variables higher_version_gmtbins and lower_version_gmtbins see sec 5 gawk The awk command family awk itself the math included version nawk and usually the GNU version gawk is available on all UNIX systems such as AIX IRIX SOLARIS HPUX or LINUX AWK or some GNU flavors of it such as gawk which is used by iGMT per default runs also on PCs and Macs To change the default awk type binary modify the iGMT variable our_awk see sec 5 If gawk is not available use nawk instead of simple awk since our scripts
11. 0 Plumes in a convecting mantle Models and observations for individual hotspots J Geophys Res 105 11127 11152 USGS NEIC 1998 National Earthquake Information Center World Data Center A for Seismology Global Earthquake Search United States Geological Survey National Earthquake Information Center http wwwneic cr usgs gov neis epic epic_global html Wessel P and Smith W H F 1991 Free software helps map and display data EOS Trans AGU 72 445 446 Wessel P and Smith W H F 1995 New version of the Generic Mapping Tools released EOS Trans AGU 76 329 Wessel P and Smith W H F 1998 New improved version of the Generic Mapping Tools released EOS Trans AGU 79 579 Zoback M L 1992 First and second order patterns of stress in the lithosphere The World Stress Map project J Geophys Res 97 11703 11728 19 Appendix A Technical details A 1 Organization of the iGMT software After unpacking the igmt_v1l 2 tar file the directory should look something like this SOLSeck COPYING formatcpt awk igmt_helper_create_ci_file COPYRIGHT igmt igmt_helper_create_man_page INSTALL TXT igmt tcl igmt_helper_handle_gmtdefaults NOTES TXT igmt_configure tcl igmt_helper_rmtmp_silent README TXT igmt_datasets tcl igmt_init tcl colminmax awk igmt_def gif igmt_iomisc tcl colormaps igmt_gmtdefaults_3 0 igmt_menus tcl configure_script igmt_gmtdefaults_3 1 igmt_parameters tcl example
12. Holland Publ Co Amsterdam EDC 1996 Global 30 Arc Second Elevation Data Set EROS Data Center Sioux Falls South Dakota Engdahl E R van der Hilst R D and Buland R 1998 Global teleseismic earthquake relocation with improved travel times and procedures for depth determination Bull Seismol Soc Am 88 722 743 Giardini D Gr nthal G Shedlock K and Zhang P 1999 The GSHAP Global Seismic Hazard Map Annali di Geofisica 42 1225 1230 Giardini D Gr nthal G Shedlock K and Zhang P 2000 The GSHAP Global Seismic Hazard Map Technical report ETH Z rich http seismo ethz ch gshap global global html Gilly D 1994 UNIX in a Nutshell O Reilly amp Associates Inc Cambridge Gudmundsson O and Sambridge M 1998 A regionalized upper mantle RUM seismic model J Geophys Res 103 7121 7136 Laske G and Masters G 1997 A global digital map of sediment thickness EOS Trans AGU 78 F483 M ller B Reinecker J and Fuchs K 2000 The 2000 release of the World Stress Map Online at www world stress map org cf Zoback 1992 M ller B Wehrle V and Fuchs K 1997a The 1997 release of the World Stress Map http www wsm physik uni karlsruhe de pub Rel97 wsm97 html 18 M ller D Roest W R Royer J Y Gahagan L M and Sclater J G 1997b Digital isochrons of the world s ocean floor J Geophys Res 102 3211 3214 http Omphacite es s
13. Y or FITNESS FOR A PARTICULAR PURPOSE GNU General Public License for more details See the E PLOTTING NO GUARANTE ES In addition we strongly suggest that iGMT users comply with the goals as expressed in the Student Pugwash Pledge www spusa org pugwash You should have received a copy of the GNU General Public License COPYING If not write to 9 Temple Plac suit 330 SId manual tex v 1 29 2005 12 13 03 32 29 becker Exp EEIEIE AEE AE a AEE a a AE AE a AEE a a aE a a aa aa a aaa a a a a aa aa a aaa a E s OF HE HEHEHE H F H F 2 Credits and history Many users have helped to improve iGMT with their comments contributions and problem reports For example Simon McClusky of MIT provided provided his velocity vector facility for iGMT 1 0 This support is very important for us and we encourage you to contact us if you find bugs or inconsistencies be it with the software itself or with this manual iGMT uses the GMT software by Wessel and Smith 1991 1995 1998 for mapping and is based on the Tcl Tk toolkit by John Ousterhout Small parts of the routines and templates were taken directly from the Tcl Tk book by Ousterhout 1993 or the GMT documentation Some of the initial Tk frame packing was done with the XF software by Sven Delmas iGMT makes use of the convert tool of the ImageMagick distribution The researchers making the data sets available that iGMT works with have to be
14. aphic format which is smaller png but for this to work a non standard extension of Tcl Tk is needed This is why we still stick to GIF and will probably change the graphic format only in the next version From now on we use the acronym GIF to refer to whatever graphic format you chose even though you might get an error message when you use Map it If you have installed the tools mentioned above you should be ready to use the basic version of iGMT While the requirements above might seem complicated it should be kept in mind that nowadays most UNIX or LINUX systems come with all of the above except GMT when the system software is installed GMT on the other hand is widely in use in the earth sciences already In addition all of the software needed to run iGMT is freeware or shareware of some kind and most of it is subjected to an open developing policy 5 Installation and configuration To get iGMT running extract the distribution igmt_v1 2 tar gz or alternatively its slim version igmt_ vl 2_wo tar gz if you have not already done so in a directory where you typically store Tcl Tk scripts This could well be at the single user level on multi user systems non root priveliges installation since the package itself is relatively small Installing multiple copies would allow every user to modify the iGMT code themselves From here you can either choose to use the script configure_script which we provide or proceed to do a few c
15. data and mapping part of the GMT script Menu items for pscoast The first three items deal with pscoast A small subset of the polygon data that can be plotted by this routine are mentioned in the Pscoast polygon selection list The next item allows changing the color of the land and sea coverage while the last pscoast item is responsible for changing some linewidths Raster data set items Toggle the automatically provided legends colorbars for the gravity age geoid and topography data sets on and off and select the grid resolution If the value you choose in arc minutes is smaller than the minimum value supported by the specific data set iGMT increases the value automatically There will be a warning when a large number of data points are about to be processed Keep in mind that small machines might have a hard time if the resolution is too high and or the map size is too big Change colormap lets the user choose a colormap other than the ones used automatically when a predefined raster data file is selected If you change the raster data set to one of the predefined ones after choosing your own colormap you have to reenter the selection Create colormap uses the GMT tool grd2cpt to automatically create a colormap for the default grd file that is set For GMT versions higher than 3 2 the user can select from different colormap schemes see the man page for grd2cpt otherwise it s rainbow Since the colormap is based on a his
16. ding new data sets You will have to do these things to be expanded 1 Add the data location and its parameters to the igmt_configure tcl file This should be easier now with version 1 2 since we have replaced most global variables for raster and polygon data issues with arrays such that you can simply add one more entry at the back Right now raster data sets are reserved from 1 to 11 with the limit being set to variable nr_of_raster_data 20 raster data sets in total Polygon data sets are restricted to 25 and right now all sets up to 20 are filled Read through igmt configure tcl to see how the default data sets are implemented here Parameters for raster data are location of data file default colormap geographical limits East West South and North boundaries integer boundaries only on off the maximum resolution in arc min utes and resampling at other than default grid spacing on off For polygon data location of data symbol size symbol color 2 Add the data selection choice to the Datasets menus This is done in igmt_menues tcl and igmt_ datasets tcl 22 3 Add the data plotting routine to igmt_plotting tcl taking the old datasets as an example Make use of the predefined standard procedures for raster data 23
17. ector field plotting and WSM parameters can be used to select the plotting type for stress data the minimum quality and the types M ller et al 2000 Finally City type selects between the full and the restricted city data set 7 4 Menu Map parameters Item Region This item brings up the region selection dialog Where the eastern northern etc boundaries are self explaining the Center of map projection is needed for whole earth viewing projections Clicking on The whole thing expands the geographical boundaries as far as possible for the checked projection Square it attempts to make a square like map by setting the difference between the boundaries equal Center sets the center of map projection values to the averages of the boundaries and adjusts the reference meridian to the average latitude needed for some projections 0 180 j z 0 360 attempts to go from one system of specifying longitudinal ranges to another Item Projection The projection order chosen for the dialog box follows the GMT manual URL http www soest hawaii edu wessel gmt gmt_doc html closely Projections themselves are explained briefly in the pscoast man page The last check box custom projection allows the user to specify the projection with the magnification factor in the GMT format explicitly This might be needed since formatting is not perfectly done by iGMT and not all GMT projections are implemented Some of the
18. h Wsize RRR GGG BBB in the final script Change this in igmt_plotting tcl if you like 14 a ee eT m a s 6000 3000 1000 0 500 1000 5000 Figure 1 ETOPO5 NUVELI plate boundaries and PDE hypocenter distribution as of examplel ps reso lution reduced Data from DeMets et al 1990 NOAA 1988 USGS NEIC 1998 be done in addition to the introduction in the GMT manual and give the experienced user a fast tool to get to a start script for more complicated applications This file is called SHOME igmt_parameters dat by default Addstufftothepscoastline lets the user add additional commands to the last pscoast command of the script file without having to exit from iGMT and run the script independently The file presented by Showscripterrors contains the stderr output of the GMT commands invoked and should be helpful for debugging By default GMT is verbose GMTversion lets the user change between the old GMT version 3 0 and one of the newer versions such as 3 4 The last item of this menu lets the user switch the GMT logo on and off By default it is off since it would interfere with the colorbars 7 6 Menu GMT help This menu list is intended to provide fast access to the GMT man pages for reference At the time of the first call a temporary file is created from the man command and afterwards displayed every time the user selects the same command man page again If the GMT man pages are not in the usual place where the
19. hanges manually If you choose the automatic way you will have to enter the iGMT directory that you just created by expanding the tar file and type configure_script After answering a couple of questions you should be all set If on the other hand you would like to stay in control simply check the following steps 1 An environment variable igmt_root can be set to point to the directory where iGMT resides With csh this would be done by adding a line like setenvigmt_root SHOME tcltk igmt_dir to the HOME login file For bash you would add exportigmt_root SHOME tcltk igmt_dir to the profile file Alternatively you will have to modify the main iGMT script startup script file igmt and change line 39 to point to the root directory 2 The igmt script calls the Tcl Tk shell wish using the explicit call to usr bin wish in line 75 If wish is somewhere else on your system try typing whichwish or typewhich either change the corresponding line in igmt or set the another environment variable Swish_cmd After verifying the settings igmt should be executable and iGMT can be started by typing Sigmt_root igmt at the command line Of course this can be facilitated by adding an alias or linking S igmt_root igmt to some place where your shell looks for executables 3 iGMT needs to know where the GMT binaries old up to 3 4 5 and new 4 0 and up are located In a similar fashion as above for wish find out where that is say
20. hat s fine but please do not call it iGMT when you distribute it and make reference to the original software Please keep in mind that while GMT offers a large number of interesting and useful mapping options and iGMT tries to make use of them iGMT can t be as flexible as GMT In addition it is pretty hard to test every single combination of what might go wrong if Hence iGMT can be expected to fail to produce useful maps under certain circumstances Of course the software is provided as is no guarantee whatsoever is given and no responsibility for possible damage is taken Hopefully iGMT demonstrates what can be done nowadays that great geophysical data sets and mapping software is available If iGMT helps in making the research work of earth scientists easier we are happy References DeMets C Gordon R G Argus D F and Stein S 1990 Current plate motions Geophys J Int 101 425 478 Dunbar P K Lockridge P A and Whitewide L S 1997 Catalog of Significant Earth quakes 2150 B C 1991 A D Report SE 49 National Geophysical Data Center Boulder Colorado http www ngdc noaa gov seg hazard sigintro html Dziewo ski A M and Woodhouse J H 1983 Studies of the seismic source using normal mode theory In Kanamori H and Boschi E editors Earthquakes observation theory and interpretation notes from the International School of Physics Enrico Fermi 1982 Varenna Italy pages 45 137 North
21. hydrostatic shape of the Earth Nakiboglu 1982 and included them in quarter arc minute resolution as a GMT grd file in our raster data set Alternatively we also offer the OSU91A model of Rapp et al 1991 as a typical geoid representation grd file You can download both files from our web site Global free air gravity Derived from the EGM360 model of Rapp et al 1991 1996 from order 2 to 360 and included in quarter arc minute resolution as a GMT grd file in our raster data set Obtained from the file above by multiplying the spherical harmonic coefficients by g 1 R where g is gravitational acceleration R the radius of the Earth and the order of the spherical harmonics You can download this file from our web site Sediment thickness Sediment thickness is important for seismological studies and the comparison be tween half space cooling model prediction and bathymetry We have included a data handling rou tines for the Laske and Masters 1997 dataset The data itself is available as a grd file on our web site GSHAP peak ground acceleration The Global Seismic Hazard Assessment Program GSHAP Giardini et al 1999 2000 has compiled a world wide 6 minute on land dataset of estimated peak ground accelerations that can be expected with a 10 probability within the next 50 years see http seismo ethz ch gshap global global html We provide a plotting facility for this type of data the grid file can be obtained from ht
22. iGMT Interactive Mapping of Geoscientific Datasets User manual for version 1 2 Thorsten W Becker Alexander Braun March 25 2007 Abstract iGMT is a Tcl Tk package for interactive mapping of geoscientific datasets built around the generic mapping tools GMT Our software is intended to assist in the creation of GMT scripts and has built in data processing capabilities for raster data sets such as topography sea floor age free air gravity the geoid and various polygon data files such as earthquake hypocentre lists or hot spot locations iGMT is used world wide at more than 220 institutions for everyday map making and teaching GMT Our program should run on any UNIX type computer since it is entirely based on open source software iGMT itself is distributed under the GNU public license but should be used in accordance with the Student Pugwash pledge This manual briefly describes how iGMT is used and explains some technical details that may be helpful if the user wishes to extent or modify iGMT Please note that some of the comments in this manual may be outdated so please proceed with caution University of Southern California Los Angeles CA USA University of Calgary Calgary Canada Contents 8 9 Copyright and warranty disclaimer Credits and history Quick start and installation instructions Software requirements Installation and configuration 5 1 Examples of modifying default variables 2 2 2
23. identical to the real postscript files produced they were too big to be included in the distribution Documentation and data The file manual ps is the manual you are reading as a postscript file nuvel yx is the modified plate boundary polygon file after DeMets et al 1990 01_02 98 cmt contains the Harvard CMT double couple fault plane solution for the first 60 days of 1998 as an example vocanoes dat the volcano locations after Simkin and Siebert 1994 allslabs_rum gmt the slab seismicity contours of Gudmundsson and Sambridge 1998 and hotspots dat the hotspot list of Steinberger 2000 Colormaps The colormaps directory contains the colormaps that are used by iGMT to map the default datasets col 00 cpt through col 35 cpt are generic colormaps which span the data range from 1 1 If you want to convert these colormaps to suit your data use an awk script like colminmax awk which comes with the iGMT distribution script to convert the data range of colorscale files for GMT by rescaling BEGIN if min 0 min 1 if max 0 max 1 mean maxtmin 2 range max min 2 printevery 50 if NR lt 256 if printevery NR gt 0 print 1 rangetmean 2 3 4 5 rangetmean 6 7 8 9 else print 1 rangetmean 2 3 4 5 rangetmean 6 7 8 9 L printevery NRtprintevery else 21 print 0 If your data sets contains values between 2 and 3 say and you would like to use the
24. iles would be the expansions of plate velocity Euler poles you can find at our website Our script can read the 1997 2000 2003 and 2005 formats of the WSM data format they are different as to the addition of the ISO field in 2000 11 Technical details how these files are handled are explained later in the text and in the comments found in igmt_plotting tcl You might also wish to refer to the iGMT web site where you can find a more detailed description of the datasets listed above and links to the sites providing the data http www seismology harvard edu sim becker igmt In addition this is where you can obtabin the plate velocity and potential field grids mentioned above 7 Usage of iGMT In the following we assume that you have a running version of iGMT The usage will be explained by going through all menu points that show up at the start up screen The basic idea of iGMT is to use GUI facilities to select important plotting parameters produce a GMT script and run it from within the program When this is done successfully the produced postscript code is converted to a GIF image and then displayed By doing this it is easy to create a basic script that can then be modified for more complex applications when the limits of iGMT are reached The menu list is divided into six pull down menus File Plot Datasets Dataparameters Mapparameters Scriptin Options and GMTmanpages as well as two buttons Mapit and Quit 7 1
25. inary format ETOPO2 topography The composite ETOPO2 topography bathymetry dataset is desribed at http www ngdc noaa gov mgg fliers 01lmgg04 html GriddedF and supported as a GMT grd file which can be obtained from http dss ucar edu datasets ds759 3 data GTOPO30 topography The GTOPO30 DEM model EDC 1996 was greatly expanded by Smith and Sandwell 1997 It is supported in the form suggested by Smith amp Sandwell using img2grd Data and other tools can be found at http topex ucsd edu marine_topo mar_topo html The img format file is 137MB Sea floor age The sea floor age data of Miiller et al 1997b was published as a GMT grdfile and is used in the form as available at http Omphacite es su oz au StaffProfiles dietmar Agegrid agegrid html The data is about 23MB in grd format and roughly 10MB in i2 binary which could be read by grdraster as ETOPOS to do this change the corresponding lines in igmt_plotting tcl By default iGMT expects the global grid file version age data version 1 5 Free air gravity Sea floor gravity anomalies as published by Sandwell and Smith 1997 are used as a grdfile as found at http topex ucsd edu marine_grav mar_grav html As GTOPO30 this file is 137MB big Geoid iGMT supports plotting the geoid and comes with an adequate colormap As an example we evaluated the spherical harmonic coefficients of the EGM360 model of Rapp et al 1991 1996 from order 2 to 360 corrected for the
26. ing data sets are wcity dat and wcity_major dat the latter is a subset of the full data set Custom xys files iGMT can plot two custom ASCII data files specified by the user They have to be in a columnar ASCII format separator is a white space or tab comment lines can be introduced by a number sign similar to the polygon data described above and need at least longitude and latitude in every line Size values can be given optionally hence xys For instance for earthquakes hypocentres you would give longitude latitude and magnitude The magnitude will be used to scale each symbol that is plotted on your map To change all symbol sizes in an absolute sense you can choose sizespolygondata in the Dataparameters menu When you use polygon drawing by choosing line or close polygon as a symbol in Symbolspolygondata for your polygon file the sizespolygondata item will change the width of the line GMT type polygon files where individual 66 9 polygons are separated by an sign in a single line are supported You can interactively choose the column numbers ie use the eight and ninth column instead of the first and second which hold the x and y values if you leave the column number for size blank xy plotting is assumed The magnification factor is a pre multiplier for the size entry that is later modified by the standard size of the symbols see also section 7 2 5 An example for such dataf
27. l dat igmt_gmtdefaults_3 2 igmt_plotting tcl example2 dat igmt_gmtdefaults_3 3 img2grd example3 dat igmt_gmtdefaults_3 4 sortwsm awk example4 dat igmt_helper_checkfile where the colormaps directory contains the color tables for GMT gt iS bathymetry cpt col iL cpt col 23 cpt colg Cpt sediment 2 cpt col 00 cpt col 12 cpt col 24 cpt col 36 cpt sediment cpt col 01 cpt col 13 cpt col 25 cpt col 37 cpt tomo cpt col 02 cpt col 14 cpt col 26 cpt col th 1 cpt tomo2 cpt col 03 cpt col 15 cpt col 27 cpt colgeoid cpt topo bw cpt col 04 cpt col 16 cpt col 28 cpt geoid cpt topo cpt col 05 cpt col 17 cpt col 29 cpt geoid2 cpt topol cpt col 06 cpt col 18 cpt col 30 cpt geoid3 cpt topo2 cpt col 07 cpt col 19 cpt col 3l cpt geoidd5 cpt topo3 cpt col 08 cpt col 20 cpt col 32 cpt gravity cpt topo4 cpt col 09 cpt col 21 cpt col 33 cpt seafloor_age cpt col 10 cpt col 22 cpt col 34 cpt seafloor_age2 cpt The files in this distribution can be classified as follows Copyright COPYING and COPYRIGHT deal with legal issues iGMT is distributed under the GNU public license but should be used in accordance with the Student Pugwash Pledge see the file COPYING configure_script This short script is supposed to take over the installation process as described in sec 5 img2grd Script from the GMT distribution that is supposed to be a patch when img2latlongrd is not available included starting from GMT 3 3 6 The igmt file A bash script that is used to
28. l events in the catalog of the first 60 days of 1998 is included as an example Significant earthquakes Dunbar et al 1997 have compiled a list of significant earthquakes starting 2000 B C their catalog is accessible at http www ngdc noaa gov seg hazard sigintro html After quoting all lines without data by inserting a hash sign the format produced by this engine can be read directly into iGMT Internally all that iGMT does is to use awk to check if lines are quoted and for exporting of the relevant columns iGMT plots only earthquakes that have a magni tude assigned you might want to change the relevant awk lines in igmt_plotting tcl PDE earthquakes The United States Geological Survey keeps different hypocenter catalogs at the Na tional Earthquake Information Center URL http wwwneic cr usgs gov neis epic epic_global html The Screen File Format can be read by iGMT 10 Slab contours Gudmundsson and Sambridge 1998 define contours of the upper edge of subducting slabs from the relocated hypocentres of Engdahl et al 1998 These seismicity contours are available from http rses anu edu au seismology projects RUM rum_download html we have included them in a format readable by GMT Velocity vectors Simon McClusky provided a routine that handles velocity solution plotting using psvelomeca A typical application would be the mapping of results from GPS studies such as the gps vel global data example we have
29. lent is available for most operating systems We have heard of successful installations on the following operating systems MacOS X 10 x SunOS 5 6 Solaris 2 5 1 2 6 HP UX10 01 DEC OSF IBM AIX 4 1 x 4 2 1 IRIX 4 0 5 6 2 6 5 and LINUX SuSE 5 1 5 2 Redhat 4 2 5 2 6 0 7 1 Debian Fedora cores Mac OSX installation is a bit trickier and described on the web page The iGMT script package that comes with this documentation some example plots and small datasets are available at the iGMT home page http www seismology harvard edu becker igmt These website are also the places to check for updates bug reports etc iGMT assumes that you have the following software installed and accessible either via the user s path variable or the binary paths set in igmt_configure tcl or the igmt_siteconfig tcl file see sec 5 This software requirement should be It will be assumed that the user has some familiarity with the UNIX operating system and basics will not be explained here for UNIX and shell scripting reference see e g Gilly 1994 Also ask your favorite system administrator if things sound Greek to you automatically fulfilled if you are running a LINUX system from any of the major distribution e g Redhat 7 1 If any of this does not make sense to you please ask your system administrator Tcl Tk iGMT is mostly written in Tcl Tk a convenient language for constructing graphical user interfaces The Tcl script language and
30. mentioned for their great contribution Besides other sources datasets of NOAA 1988 Smith and Sandwell 1997 Sandwell and Smith 1997 Miiller et al 1997b Dunbar et al 1997 DeMets et al 1990 Steinberger 2000 Simkin and Siebert 1994 Dziewo ski and Woodhouse 1983 and Rapp et al 1991 are processed by iGMT iGMT was formerly known as A GIS which stands for A Geophysical Information System Since the program has no full GIS functionality yet we changed the name to avoid confusion Further details of the version history can be found at iGMT s web site We officially announced iGMT in 1998 in EOS Transactions the newspaper of the American Geophys ical Union A reference to cite iGMT is therefore Thorsten W Becker and Alexander Braun New program maps Geoscience data sets interactively EOS Transactions 79 505 1998 and we encourage you to mention iGMT if you find it helpful May we also suggest that you register at http op gfz potsdam de igmt userform html so that we can keep you posted if we discover bugs or a new version comes out In addition we are always eager to add your dot to our user distribution maps which can be found at http op gfz potsdam de igmt users html All that s missing is basically some geographical sorting which could be implemented using GMT functions as well 3 Quick start and installation instructions 1 Make sure you have a working version of Unix Tcl Tk and GMT
31. might rely on math functions which might or might not be accessible from within awk ghostview iGMT uses the GNU software ghost view as a postscript display program A possible postscript viewer alternative would be showps or ghost script available for PC and Mac change iGMT vari able psviewer see sec 5 iGMT works fine without any postscript displayer at all as long as you do not need to view the PS files that GMT produces before printing them convert The convert tool of the ImageMagick software http www wizards dupont com cristy ImageMagick html is used to convert from PS to the GIF format so that GMT output can be judged right away GGMT variable ps_to_gif_converter see sec 5 You might as well use ghost script to convert from postscript or change the graphic format that is used for previewing to something completely different gt iGMT works fine without a converting tool 3At the moment standard Tcl photo image displaying works only with GIF and ppm images Since ppms are usually much bigger than GIF images we chose GIF to be the standard If you choose ppm not interfering with possible copyright issues and continue to use convert just change the name of the converted file for convert in igmt_siteconfig tcl to have a ppm suffix For ghostscript you need to change the command line used for the conversion operating system call see the comments in the igmt_configure tcl file User E Suarez has implemented another gr
32. own to iGMT1 0 Displaymanual displays this manual with the postscript software if installed and About iGMT shows a short description of the software 7For ease of use these menus can be detached under Tcl Tk by choosing the dashed line on top of each list and moving them to the work space 12 7 2 Menu Datasets The first item in the Datasets menu leads to the raster data choice dialog where the files to choose from are those described in section 6 The same holds true for the polygon datasets of the second item In contrast to the raster data sets polygon sets can be plotted on top of each other Future versions of iGMT will allow multiple layers of raster data as well The next part of the Datasets menu allows the user to choose the custom GMT grd file he wants to plot whereas Change file in the next six lines modify the respective custom polygon data files The polygon menu comes with the option of plotting two user defined data sets as mentioned above The following two items in the menu list bring up two identical dialogs where the names of the custom xys files the columns for latitude longitude and size as well as a magnification factors for the size can be specified Internally all data sets are of course handled by a trivial awk script that can be viewed in the GMT script file or in the source code that is igmt _plotting tcl 7 3 Menu Data parameters This and the next menu are used to set all the parameters for the
33. projections adjust the geographic region to be plotted as suitable Items for map grid line and frames Gridlines and Frame annotation are on off type switches By default the gridlines are twice as densely spaced as the outer annotation intervals along the map frame You can choose to annotate on all four sides of the plot default or only on the southern and eastern sides The mapscale the user can switch on by selecting Fancy Plain or Off is positioned in the lower left corner of the map and calculated to be correct at center latitudes Miscellaneous plotting items Add a title to the plot and change the page size and orientation here The offsets in x and y direction default to one inch each which is usually ok Don t expect perfect results in terms of title placement or centering of the final map on the produced postscript file though Reasonable results should be achievable with the built in functions of iGMT while final copies will probably need some hands on modification of the GMT script 7 5 Menu Script The first item Show GMT script shows the file that is created and executed by iGMT to get GMT to produce the postscript file we are viewing This is intended to do two things Show the inexperienced user what can 8Some symbols disregard the G option e g crosses so that they will appear in boring black whatever you do with the color sliders You will have to fix this by replacing the GRRR GGG BBB option wit
34. this should be fine on most Linux like systems and on OS X once GMT is installed via fink Particularly every user will have to have SGMTHOME set properly see the GMT documentation 2 Install the iGMT tcl source code and smaller datasets into some directory say usr local src igmt_1 2 by typing cd usr local src gunzip e igmt_v1l 2 20051208 tar gz tar xv cd igmt_1 2 configure_script where the last step should make sure that the main paths are set properly 3 If you want a shortcut to install all the geophysical data we list on http www seismology harvard edu becker igmt you can download a 300MB big gzipped tar file from href http geodynamics usc edu becker ftp igmt_data_comp tgz Remember that we are providing this collection only for your convenience that all copyrights remain with the original authors and the obligation to properly cite lies with you If you decide this package put the tar file to some shared directory say wrk data it will expand into subdirectories that hold most of the data that is listed below What follows is a long version of the installation and software documentation 4 Software requirements The current version of iGMT is intended for use on UNIX systems and was first developed running IRIX 6 3 6 5 and from 2002 on purely on Linux However it should be easily modified to run on other hardware platforms without much effort since all the software that iGMT relies on or an equiva
35. togram of the grd file colormap creation might take a while with slow machines and or large datasets Use Shade raster data to toggle the shading that is done for topographic and gravity datasets using grdgradient Following is the Contour lines item which you can use to switch the plotting of contour lines of the grdfile values to overlay on top of grdimage produced plot only contourlines solely or off In addition you can select the color of contour lines set the width of contour lines the contour line density and the annotation text size By default iGMT will use black for the color contour line density of unity which corresponds to on the order of ten contour lines linewidth 2 for normal lines Every second contour line is annotated and has double width Also annotations will be 14pt size set them to if no annotation is wanted 13 Polygon data setitems The next four menu items change roughly what they say Symbols Sizes Color and Linewidths of the polygon data Sizes are in fractions of the mapwidth and get multiplied by another factor with the size column of the xys data The symbols types that are implemented are again only a subset of what GMT can do Name tags can be switched on and off for hot spots and volcano data sets with the next item GPS velocity vector parameters is used to adjust the parameters for the GPS psvelo vectors Vector field pa rameters is used to adjust v
36. tp seismo ethz ch gshap global caution html Custom data You can choose an arbitrary GMT grd file to be plotted as the base data layer and provide your own colormap too 6 2 Polygon data Some example handling procedures for polygon data are included as well Plate boundary data The plate boundaries as given by DeMets et al 1990 are part of the iGMT distri bution as the file nuvel yx ina slightly modified form Any polygon data file supported by psxy can be substituted for this data set Hotspot locations iGMT uses a list of hotspots compiled by Steinberger 2000 to plot their location and a name tag if selected Volcano locations The Smithsonian Institution Global Volcanism Program s list of volcanoes Simkin and Siebert 1994 is supported in the form found at http www volcano si edu gvp volcdata index htm As for the hotspot data the user can select a symbol the color and toggle a name tag A version of this list as of April 1998 is included If you want to install an update just download the data from the web and replace the adequate file The same holds true for the earthquake catalogs since iGMT was programmed to handle the original data CMT fault plane solutions iGMT uses psvelomeca from the GMT supplements package to plot the dou ble couple part of the Harvard CMT centroid moment tensor solutions e g Dziewonski and Wood house 1983 as found at http www seismology harvard edu CMTsearch html A list of al
37. u oz au StaffProfiles dietmar Agegrid agegrid html Nakiboglu S M 1982 Hydrostatic theory of the Earth and its mechanical implications Phys Earth Planet Inter 28 302 311 NOAA 1988 Data Announcement 88 MGG 02 Digital relief of the Surface of the Earth National Geophysical Data Center Boulder Colorado http www ngdc noaa gov Ousterhout J K 1993 TCL and the TK Toolkit Addison Wesley Reading MA Rapp R H Wang Y M and Pavlis N 1991 The Ohio State 1991 geopotential and sea surface to pography harmonic coefficient models Rep 410 Dept of Geod Sci and Surv Ohio State University Columbus Ohio Rapp R H Zhang C and Yi Y 1996 Analysis of dynamic ocean topography using topex data and orthonormal functions J Geophys Res 101 22583 22598 Reinecker J Heidbach O and Miiller B 2003 The 2003 release of the World Stress Map Online at www world stress map org Sandwell D T and Smith W H F 1997 Marine gravity anomaly from Geosat and ERS 1 satellite altimetry J Geophys Res 102 10039 10050 Simkin T and Siebert L 1994 Volcanoes of the World Geoscience Press Tucson Arizona 2nd edition http www volcano si edu gvp volcdata index htm Smith W H F and Sandwell D T 1997 Global seafloor topography from satellite altimetry and ship depth soundings Science 277 195 196 http topex ucsd edu marine_topo mar_topo html Steinberger B 200
38. variables The GMT binaries are not in the path the shell checks routinely Therefore search for the corresponding iGMT variable in igmt_configure tcl Its name is gmtbins and it is set to by default ie only the normal path is searched To change this behavior modify or create a file named igmt_siteconfig tcl and include the line set gmtbins path bin where path is the location of your GMT commands Similarly if the man pages are not accessible by default change the set gmtmanpage command If you don t have gawk on your system change the default awk like program by resetting the variable Sour_awk to whatever your awk is called maybe awk 6 Datasets handled by iGMT While iGMT is lacking the database query functions of full blown GIS systems it is capable of combining multiple geoscientific data sets and handling large amounts of data in an efficient way Indeed this is an achievement of the GMT software and iGMT s approach does not constrain this feature Excellent data is available on the web these days and iGMT is based upon these publicly available collections Since GMT has grown into a de facto standard in parts of the geophysical community it seems natural to use GMT to handle the data With the requirements that are explained in section 4 you should now be able to interactively use the GMT command pscoast that is used for plotting maps of land and sea coverage with political boundaries etc 4 If you want to take
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