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CONVERT – A Format-conversion Package

1. E 5 19 Release Notes V1 8 NDF2FITS has a new literal parameter called AXISORDER to specify the order of WCS axes in the output FITS header This is introduced so that the generated FITS file may be interpeted correctly by those FITS readers that assume certain axis orders For example some expect equatorial co ordinates to be ordered right ascension then declination whereas the FITS standard lets you permute WCS axes in any order
2. Usage da2ndf in out comp noperec shape type Parameters COMP LITERAL Read The NDF component to be copied It may be Data Quality or Variance To create a variance or quality array the NDF must already exist Data IN FILENAME Read Name of the input direct access unformatted file NOPEREC _INTEGER Read The number of data values per record of the input file It must be positive The suggested default is the size of the first dimension of the array A null value for NOPEREC causes the size of first dimension to be used OUT NDF Read and Write Output NDF data structure When COMP is not Data the NDF is modified rather than a new NDF created It becomes the new current NDF Unusually for an output NDF there is a suggested default the current value to facilitate the inclusion of variance and quality arrays SHAPE _INTEGER Read The shape of the NDF to be created For example 40 30 20 would create 40 columns by 30 lines by 10 bands TYPE LITERAL Read The data type of the direct access file and the NDF It must be one of the fol lowing HDS types _BYTE _WORD _REAL _INTEGER _INT64 _DOUBLE _UBYTE _UWORD corresponding to signed byte signed word real 64 bit inte ger integer double precision unsigned byte and unsigned word respectively See SUN 92 for further details An unambiguous abbreviation may be given TYPE is ignored when COMP Quality since the QUA
3. GASP2NDE GIPFANDE ss ses ce ead fo oN BAe ASS TRAF2NDF 2 00 e eee IRCAM2NDE MITFITS2NDE s oe e pod e e a aa a Aa NDF2ASCII NDEDA re e064 ae ek ee eA EE eet NDE2DST NDE2EITS e ore toee ee NDF2GASP Se ee ee p a e a ee ee Mets ea a eee Sees oe Se we eee ee ee E eae oe oe gy ar eee ee Se ee ee es ee ee ee ee ee TEETE ee ee ee See Ea a Be oe ee ee See ee ee ee ee eee B Handling NDFs in IDL B 1 The Easy Way 406 ba ae 6 ee ee eS ew B 2__ Other Methods B 2 1 A simple route but rather slow SUN 55 31 Contents 92 aoe ee a ek ae i a eo 92 SUN 55 31 Contents iv B 2 3 Using the IDL Astronomy Users Library 0 95 C Specifications of CONVERT IDL Procedures 96 READ NDI esata dee ae ele bee Es ee eee ok het eS 97 WRITE_NDF 0 000 0 0 00 eee ee eee 99 HDS2TDE 3 se sew eee wR ee RoR RS Reh ee ee ee eee RS 102 IDL2ZHDS 24 e460 eee ewe ee wea oe awe SP RR we Rw ew Sa 104 106 E Release Notes 106 E 1 3 Documentation E 2 Release Notes V1 2 4 2 ee 107 E 3 Release Notes V1 3 2 2 ee ee 107 We Biko eta a eee ee ee ee 108 Cae Gye ore SS ea See eee eee ee 108 Sey Shs eee an Sele oa ee eee eee ee 108 os BA Ades Eee ae oe oa aes 108 ee ee re eee eee nee ee eee 108 oS Se ote ee ee eee bees 108 Se eee Se Oe eee ae a 108 C2 bet ee eee ent ew YP 2 ee ee 109 Lee ee aes Pees 2 enue eee ee T 109 a eee Soh eh ee ee a eee ee Ee 109 oe
4. The shape of the NDF to be created For example 40 30 20 would create 40 columns by 30 lines by 10 bands It is only accessed when FITS is FALSE SKIP INTEGER Read The number of header records to be skipped at the start of the input file before finding the data array or FITS like header 0 TYPE LITERAL Read The data type of the output NDF It must be one of the following HDS types BYTE _WORD _REAL _INTEGER _INT64 _DOUBLE _UBYTE _UWORD corresponding to signed byte signed word real integer 64 bit integer double pre cision unsigned byte and unsigned word See SUN 92 for further details An SUN 55 31 Specifications of CONVERT Applications 14 ASCIIZNDF unambiguous abbreviation may be given TYPE is ignored when COMP Quality since the QUALITY component must comprise unsigned bytes equivalent to TYPE _UBYTE to be a valid NDF The suggested default is the current value TYPE is only accessed when FITS is FALSE _REAL Examples ascii2ndf ngc253 dat ngc253 shape 100 60 This copies a data array from the text file ngc253 dat to the NDF called ngc253 The input file does not contain a header section The NDF is two dimensional 100 elements in x by 60 in y Its data array has type _REAL ascii2ndf ngc253q dat ngc253 q shape 100 60 This copies a quality array from the text file ngc253q dat to an existing NDF called ngc253 such as created in the first example The input file does not
5. of the FITS file specified by the IN parameter and its VARIANCE from the second NDF OBS_1 will have an extension named CAL created from the third FITS extension NDF OBS_2 has DATA and VARIANCE components created from the FITS sub files whose EXTNAME keywords have the value IM4 and IM5 respectively no CAL extension is created in OBS_2 SUN 55 31 Specifications of CONVERT Applications 26 FITS2NDF OBS_3 DATA and VARIANCE are created from FITS sub files named IM7 and IM8 and the CAL extension from the FITS sub file whose EXTNAME and EXTVER key words have values CAL and 2 respectively In all cases if the PROFITS parameter is TRUE the NDF s FITS extension will be created from the header of the sub file associated with the DATA component of the NDF It will have the form of a primary header and may include cards inherited from the primary header FMTCNV LITERAL Read This specifies whether or not format conversion will occur The conversion applies the values of the FITS keywords BSCALE and BZERO to the FITS data to generate the true data values This applies to IMAGE extensions as well as the primary data array If BSCALE and BZERO are not given in the FITS header they are taken to be 1 0 and 0 0 respectively If FMTCNV FALSE the HDS type of the data array in the NDF will be the equiv alent of the FITS data format on tape e g BITPIX 16 creates a WORD array If TRUE the data array in the NDF will be converte
6. CUNITn are used to create the NDF axis centres labels and units The OBJECT LABEL BUNIT keywords define the NDF s TITLE LABEL and UNITS components respectively if they are defined 37 FITS2NDF SUN 55 31 Specifications of CONVERT Applications HISTORY cards in a special format created by NDF2FITS are converted back into NDF history records The NDF variance is derived from the data array of an IMAGE extension usually the first if present provided the IMAGE extension headers have an HDUCLAS2 keyword whose value is either VARIANCE or ERROR The NDF_CLASS extension within the NDF is filled using the a FITS binary table extension whose EXTNAME keyword s value is NDF_CLASS Note no error is reported if this extension does not exist within the FITS file The FIBRES extension is created from another FITS binary table whose EXTNAME keyword s value is FIBRES The OBJECT substructure s compo nent names data types and values are taken from the binary table columns themselves and the components of the FIELD substructure are extracted from recognised keywords in the binary table s header Note no error is reported if this extension does not exist within the FITS file A FITS extension in the NDF may be written to store the primary data unit s headers when Parameter PROFITS is TRUE This FITS airlock will not contain any NDF style HISTORY records Referetitey J A 1997 2d F Software Report 14 version 0
7. kkkkkkkk 2 kkkkkkkk 1 123456789 Figure 1 Example of a map schematic SUN 55 31 Specifications of CONVERT Applications 88 TIFF2NDF TIFF2NDF Converts a TIFF file into an NDE Description This Bourne shell script converts a 256 grey level or black and white dithered Tag Image File Format into an unsigned byte NDF file It handles one or two dimensional images The script uses various NETPBM utilities to produce a FITS file flipped top to bottom and then FITS2NDF to produce the final NDF Error messages are converted into Starlink style preceded by Usage tiff2ndf in out Parameters IN FILENAME Read The name of the TIFF file to be converted A tif name extension is assumed if omitted OUT NDF Write The name of the NDF to be generated without the sdf extension If this is omitted the value of the IN parameter is used Examples tiff2ndf old new This converts the TIFF file old tif into an NDF called new in file new sdf tiff2ndf horse This converts the TIFF file horse tif into an NDF called horse in file horse sdf Notes The following points should be remembered e This initial version of the script handles only greyscale or b w dithered images You are responsible for conversion of your images to this format prior to use including the conversion of RGB values to brightness values e Input image file names must have the extension tif e The NETPBM utilities tifftopnm
8. 5 NASA Office of Standards and Technology 1994 A User s Guide for the Flexible Image Transport System FITS version 3 1 NASA Office of Standards and Technology 1995 Definition of the Flexible Image Transport System FITS version 1 1 Related Applications CONVERT MTFITS2NDF NDF2FITS KAPPA FITSDIN FITSIN SUN 55 31 Specifications of CONVERT Applications 38 GASP2NDF GASP2NDF Converts an image in GASP format to an NDF Description This application converts a GAlaxy Surface Photometry GASP format file into an Usage gasp2ndf in out shape Parameters IN FILENAME Read A character string containing the name of GASP file to convert The extension should not be given since dat is assumed OUT NDF Write The name of the output NDF SHAPE 2 _INTEGER Read The dimensions of the GASP image the number of columns followed by the number of rows Each dimension must be in the range 1 to 1024 This parameter is only used if supplied on the command line or if the header file corresponding to the GASP image does not exist or cannot be opened Examples gasp2ndf m3i_gasp m31 Convert a GASP file called m31_gasp dat into an NDF called m31 The dimen sions of the image are taken from the header file m31_gasp hdr gasp2ndf n1068 ngc1068 shape 256 512 Take the pixel values in the GASP file n1068 dat and create the NDF ngc1068 with dimensions 256 columns by 512 rows Notes e A GASP image is lim
9. Axis 3 is frequency in units of GHz The nature of these axes can be changed if necessary by subsequent use of the WCSATTRIB application within the KAPPA package For compatibility with older applications AXIS structures may also be added to the output cube see Parameter AXIS Axes 1 and 2 are offsets from the central position of the map with units of seconds of arc and Axis 3 is frequency offset in GHz relative to the central frequency The pixel origin is placed at the source position on Axes 1 and 2 and the central frequency on Axis 3 SPECX2NDF reads map files in Version 4 2 or later of the SPECX data format If it is given a map file in an earlier version of the data format it will terminate with an error message Note however that SPECX itself can read map files in earlier versions of the SPECX format and convert them to Version 4 2 Schematic of the map grid SPECX2NDF has an optional facility to write a crude schematic of the grid of points observed on the sky to an ASCII text file suitable for printing or viewing on a terminal screen This schematic can be useful in interpreting displays of the data cube It shows the positions on the grid where spectra were observed Each spectrum is numbered within the SPECX map structure and the first nine are shown using the digits one to nine The remaining spectra are shown using an asterisk You specify the name of the file to which the schematic is written Figure I shows an example of a
10. EXTNi name form specifies the name name of an NDF extension to be created name may be omitted in which case FITS_EXT_n is assumed where n is the FITS sub file number i comprises any characters and may be omitted it serves to differentiate component specifiers where the default name is to be used e sub file_specifiers is a list of FITS sub file specifiers separated by commas The nth sub file specifier from each component specifier record forms a sub file set and each sub file set will be used to create one NDF in the output file Each sub file specifier may be An integer specifying the FITS Header and Data Unit HDU number The primary HDU number is 0 keyword value case insensitive specifying a FITS HDU where the specified keyword has the specified value e g EXTNAME IM2 The keyword may be omitted in which case EXTNAME is assumed Multiple keyword value pairs separated by commas and enclosed in may be given as a single sub file specifier All the given keywords must match the sub file header values Omitted to indicate that the component is not required for the corresponding NDF Commas may be needed to maintain correct sub file set alignment for later sub file specifiers If the last character of sub file_specifiers is comma it indicates an omitted specifier at the end Note that if a sub file is not specified for the DATA component of an NDF an error will be reported at closedown e trans formation_code
11. Examples IDL gt idl2hds data_struct my_file Assuming data_struct is an IDL structure this creates the HDS file my_file sdf with a corresponding structure 105 IDL2HDS SUN 55 31 Specifications of CONVERT IDL Procedures Deficiencies e It is not possible to obtain an identical structure in all cases see Notes e It is not possible to produce HDS components of type _UWORD or _BYTE e Complex values are not handled e IDL arrays of more than 1 structure are not handled e Only a complete HDS file can be written Related Applications CONVERT HDS2IDL SUN 55 31 Release Notes 106 D _IRAF Versions The CONVERT utilities NDF2IRAFland IRAF2NDFlare built using copies of relevant IRAF libraries which are included in the CONVERT release so they exhibit the same behaviour as the IRAF version from which the libraries were extracted There are also some IRAF dependencies in the so called SPP routines of CONVERT these originate written in the IRAF SPP language and include header files defining the layout of the IRAF image The versions of IRAF2NDF and NDEF2IRAF which you use must therefore be compatible with the version of IRAF which you are using A new version of the IRAF image format was developed for IRAF Version 2 11 onwards IRAF Version 2 11 onwards will read either the old or new image formats but will produce the new format by default It can be made to produce old format images by setting environ
12. ICL gt DST2NDF old new both instruct the application DST2NDF to convert the DST file called 0ld dst to the NDF called new sdf Note that for UNIX the case of the filename is significant The following example has the same effect as those immediately above only this time you are prompted for the filenames needed by DST2NDF ICL gt DST2NDF IN Name of Figaro DST file to be converted gt old OUT Name of output NDF f1 gt new 2The con_ lt name gt form is defined for use where there may be confusion between commands of the same name from different packages SUN 55 31 Running CONVERT 6 The value between the delimiters is a suggested default You can choose to accept the suggestion by pressing carriage return The simple usage lt application gt lt in gt lt out gt will usually produce a result but many appli cations have additional parameters which you can set to give finer control over the conversion See thelapplication specifications in Appendix A for details of the options available You can find details of how to use parameters for controlling Starlink program options in Section 4 of SUN 95 or in Chapter 8 of SG 4 However you should be able to get along using intuition alone or perhaps by consulting the application specifications in Appendix A which include usage parameters examples and details of the conversion process In most cases one invocation of a CONVERT application is req
13. TRUE then it copies the headers of a valid WCS specified in the NDF s FITS airlock Should that attempt fail the last resort tries the NDF AXIS component if it exists If its co ordinates are non linear the AXIS co ordinates may be exported in a TAB sub file subject to the value of Parameter USEAXIS OBJECT LABEL BUNIT the values held in the NDF s TITLE LABEL and UNITS components respectively are used if they are defined otherwise any values found in the FITS extension are used provided Parameter PROFITS is TRUE For a variance array BUNIT is assigned to lt unit gt 2 where lt unit gt is the DATA unit the BUNIT header is absent for a quality array DATE is created automatically ORIGIN inherits any existing ORIGIN card in the NDF FITS extension unless you supply a value through parameter ORIGIN other than the default Starlink Software EXTNAME is the array component name when the EXTNAME appears in the primary header or an IMAGE sub file In a binary table derived from an NDF extension EXTNAME is the path of the extension within the NDF the path separator being the usual dot The path includes the indices to elements of any array structures present the indices are in a comma separated list within parentheses If the component is too long to fit within the header 68 characters EXTNAME is set to 9EXTNAMEF The full path is then stored in keyword EXTNAMEF using the HEASARC Long strin
14. Then to make the CONVERT commands known to the command language type ICL gt CONVERT 5 SUN 55 31 Running CONVERT This will produce a CONVERT startup message similar to CONVERT commands are now available Version 1 0 1997 August Defaults for automatic NDF conversion are set Type CONHELP or HELP CONVERT for help on CONVERT commands Type showme sun55 to browse the hypertext documentation The ICL command CONVERT is defined by the standard Starlink ICL login files to LOAD file convert icl in the CONVERT executables directory Non Starlink sites must make their own arrangements 2 3 Issuing CONVERT Commands Having initialised CONVERT you are now ready to issue a CONVERT command To run an application you can just give its name or its name preceded by con you will be prompted for any required parameters Alternatively you may enter parameter values on the command line specified by position or by keyword If you want to override any defaulted parameters then you specify the parameter s value on the command line Note that from UNIX the commands are in lowercase whereas from ICL the case does not matter Most CONVERT applications can be run as simply as lt application gt lt in gt lt out gt where lt application gt is the application s name lt in gt is the input file and lt out gt is the output file following the conversion For instance from the UNIX shell dst2ndf old new or from ICL
15. Z RANGE MORE FIGARO SECZ gt OBS SECZ MORE FIGARO TIME gt OBS TIME MORE FIGARO xxx gt XXX recursively FITS extension MORE FITS Items gt FITS xxx Comments gt COMMENTS xxx Other extensions MORE other gt MORE other Related Applications CONVERT DST2NDF 57 NDF2FITS SUN 55 31 Specifications of CONVERT Applications NDF2FITS Converts NDFs into FITS files Description This application converts one or more datasets into FITS format files NDF2FITS stores any variance and quality information in IMAGE extensions sub files within the FITS file and it uses binary tables to hold any NDF extension data present except for the FITS airlock extension which may be merged into the output FITS file s headers You can select which NDF array components to export to the FITS file and choose the data type of the data and variance arrays You can control whether or not to propagate extensions and history information The application also accepts NDFs stored as top level components of an HDS container file Both NDF and FITS use the term extension and they mean different things Thus to avoid confusion in the descriptions below the term sub file is used to refer to a FITS IMAGE TABLE or BINTABLE Header and Data Unit HDU Usage ndf2fits in out comp bitpix origin Parameters ALLOWTAB _LOGICAL Read If TRUE tables of world co ordinates may be written using the
16. ae ee ese Bae Eee a ee ee 109 oe ae eee Bes ee ee ee we ee es 109 oe Marge Boy ES ee es Se he Se ee A 110 big oe ees oh Hee He ee oS Seren ea 110 See RON ee a E of ee as eae 110 ead oe ete RE ey ee ous Se ee F 110 oat ak a eS eee Cee ee Se eee 110 ote De eee ae ee ate de eee eee 110 eee ee ee ee ae Bee eee BG 111 2 Sree pa OS bee eee ee ee ee 111 A EESE Sere BY Opies eo eects ele ear eee 111 died amp Sok Bo ea ee ee eee ee 111 Se pce E E ee Se ee 111 Let oMeee ORG Bee ats tee eee 112 Suet Bee ee ee ee a Pee Eee ee a 112 e Gre e a ae bes See ee ee ee 112 a ea a aa ee Se eee ee ee 112 List of Figures 1 Example of a map schematic SUN 55 31 List of Figures 1 SUN 55 31 Introduction 1 Introduction If life were simple there would only be one data format but in reality there are numerous formats for storing n dimensional astronomical data associated with various software packages In Starlink we have not been immune to this having the original INTERIM BDF HDS IMAGE format and FIGARO DSTs to name but three However Starlink is now taking the novel approach NDE of supporting different packages sharing a common data format the l Extensible n Dimensional data format which most Starlink packages are already using The purpose of CONVERT is the interchange of data files to and from the NDF Thus it enables astronomers to select the best applications from a variety of packages including those originating abroad
17. celestial as used by the AIPS project FITS CLASS This uses the conventions of the CLASS project CLASS is a software package for reducing single dish radio and sub mm spectroscopic data It supports double sideband spectra See the GILDAS manual DSS This is the system used by the Digital Sky Survey and uses keywords AMDXn AMDYn PLTRAH etc NATIVE This is the native system used by the AST library see SUN 210 and provides a loss free method for transferring WCS information between AST based applications It allows more complicated WCS information to be stored and retrieved than any of the other encodings Values for FITS keywords generated by the above encodings will always be used in preference to any corresponding keywords found in the FITS extension even if PROFITS is TRUE If this is not what is required the WCS component of the NDF should be erased using the KAPPA command ERASE before running NDF2FITS Note if PROFITS is TRUE then any WCS related keywords in the FITS extension which are not replaced by keywords derived from the WCS component may appear in the output FITS file If this causes a problem then PROFITS should be set to FALSE or the offending keywords removed using KAPPA FITSEDIT for example Provenance The following PROVENANCE headers are written if parameter PROVENANCE is set to Generic PRVPn is the path of the nth NDF PRVIn is a comma separated list of the identifiers of the d
18. command does not define the synonyms due to a limitation of ICL Thus NDF_FORMATS_IN is defined to be the following FITS fit FIGARO dst IRAF imh STREAM das UNFORMATTED unf UNFO dat ASCII asc TEXT txt GIF gif TIFF tif GASP hdr COMPRESSED sdf Z GZIP sdf gz When creating an output file there is a similar list of recognised formats The CONVERT startup procedures define NDF_FORMATS_OUT as follows gt FITS fit FIGARO dst IRAF imh STREAM das UNFORMATTED unf UNFO dat ASCII asc TEXT txt GIF gif TIFF tif GASP hdr COMPRESSED sdf Z GZIP sdf gz The leading dot indicates that if you omit the file extension the output file will be an NDF There are some examples of the automatic system in action and use of NDF_FORMATS_IN and NDF_FORMATS OUT in SUN 95 Section 15 1 4 Automatic HISTORY Creation The NDF data format offers a means by which processing commands and user comments may be recorded so that at some future time you can determine how a given NDF was created History recording is optional However now massive storage is cheap we recommend that you routinely use NDF history recording History recording may be enabled on an NDF by NDF basis using the SUN 95 command HISSET as described in the NDF History section of SUN 95 In the case of CONVERT this has a disadvantage the CONVERT conversion command will be absent from the NDFs created by the
19. commas and enclosed in The file specifiers indicate which files from the tape are to be processed For example 2 indicates the second file on the tape 4 6 indicates files 4 to 6 5 indicates file 5 to the last file on the tape 1 3 5 7 indicates files 1 3 4 5 and 7 to the end of the tape If no file specifiers are given all files on the tape will be processed OF LITERAL Read Name prefix of the intermediate FITS file s copied from the tape Only set this if you want to save the intermediate FITS file s If a number of files are being produced the name should contain a which will be replaced by the corresponding FITS tape file number If OF is not specified mtf 2ndf fits will be used and deleted See also Notes OUT NDF Write The name of the NDF s to be produced by FITS2NDF This is passed to FITS2NDF but only a single element string can be specified it can contain the matching patterns allowed for FITS2NDEF for example lt fits2ndf_pars gt Other parameters will be passed to FITS2NDF see the description of Notes e This application is a tcsh script which calls an ADAM A task CONVERT startup sets alias mtfits2ndf to tcsh mtfits2ndf tcsh and tcsh must be on the user s PATH e The string specified for the intermediate FITS file name s will be presented as the IN parameter for the FITS2NDF call All files matching the string will be used whether or not they were produced in this run
20. level of the output file Directive records have in column 1 and will generally be treated as comments and ignored An exception is a record starting with END which may optionally be used to terminate the file Each HDU of the FITS file is processed in turn If it matches one of the sub file specifiers in the table it is used to create the specified component of the appropriate NDF in the output file otherwise the next HDU is processed The table is searched in sub file set order If a table entry is matched it is removed from the table this means that the same FITS sub file specifier may be repeated for another NDF component but each FITS HDU can only be used once If sub file specifiers remain unmatched at the end a warning message is displayed A simple example of an EXTABLE is A simple example DATA 0 1 2 3 4 5 6 END The primary HDU and sub files 1 6 of the FITS file will be written as the DATA com ponents of NDFs EXTN_SET1 EXTN_SET7 within the HDS container file specified by the OUT parameter A contrived example showing more of the facilities is A contrived example NDFNAMES obs_ DATA 1 EXTNAME IM4 IM7 none VARIANCE 2 im5 im8 EXTN CAL 3 extname cal extver 2 END The HDS container file specified by the OUT parameter will contain three NDFs the NDENAMES record specifies that they will be named OBS_1 OBS_2 and OBS_3 NDF OBS_1 will have its DATA component created from the first extension HDU 1
21. scale the data FMTCNV along with the number of significant characters in the keywords decide the data type of the array It is expected that this will be REAL if FMTCNV is TRUE and _WORD otherwise The quality array comes from the IMAGE extension of the FITS file The twos complement values are divided by 128 to obtain the most significant 8 bits of the 14 in use There is no check that the dimension and axis defining FITS headers in this extension match those of the main data array The standard indicates that they will be the same The FILENAME header value becomes the NDF s TITLE component The BUNIT header value becomes the NDF s UNITS component x The CDELTn CRPIXn and CRVALn define the axis centres CTYPEn defines the axis labels Axis information is only available for the SILO and SIHI products The primary headers may be written to the NDF s FITS extension when Parameter PROFITS is TRUE e IVE Final Archive MXLO This will usually be a single 1 dimensional NDF however if the binary table contains two rows a pair of NDFs are stored in a single HDS container file whose 33 FITS2NDF SUN 55 31 Specifications of CONVERT Applications name is specified by parameter OUT The name of each NDF is either SMALL or LARGE depending on the size of the aperture used Thus for OUT ABC the small aperture observation will be in an NDF called ABC SMALL Only the most significant 8 bits of the quality flags are transferr
22. schematic Auxiliary information SPECX2NDF copies all the auxiliary information present in the original map file to the output data cube However the arrays holding the original spectra are not copied in order to save disk space Input and output spectra formats In addition to converting SPECX map files this application can also convert HDS files which hold an array of one dimensional NDF structures each being a single spectrum SUN 55 31 Specifications of CONVERT Applications 86 SPECX2NDF extracted by SPECX Since arrays of NDFs are not easily accessed this application extracts each NDF from the array and creates a new scalar NDF holding the same data within the output container file The name of the new NDF is SPECTRUMn where n is its index within the original array of NDFs Each new scalar NDF is actually three dimensional and has the format described above for an output cube i e Axes 1 and 2 are RA and DEC and Axis 3 is frequency However pixel Axes 1 and 2 span only a single pixel the size of this single spatial pixel is assumed to be half the size of the resolution of the JCMT at the central frequency Inclusion of three dimensional WCS information allows the individual spectra to be aligned on the sky for instance using the KAPPA WCSALIGN task 87 SPECX2NDF SUN 55 31 Specifications of CONVERT Applications Schematic map grid for C021 9 8 8765432 T RRR KAKO 6 pe 5 kkkk xxk 4 kkkkkkkk 3
23. the name since sdf is appended by the application Since the NDF_ library is not used a section definition may not be given following the name The file name is limited to 80 characters Examples dst2ndf old new This converts the Figaro file old dst to the NDF called new in file new sdf The NDF has the simple form dst2ndf horse horse p This converts the Figaro file horse dst to the NDF called horse in file horse sdf The NDE has the primitive form Notes The rules for the conversion of the various components are as follows SUN 55 31 Specifications of CONVERT Applications 20 DST2NDF Figaro file NDF Comments Z DATA gt DATA_ARRAY DATA when FORM SIMPLE Z DATA gt DATA_ARRAY when FORM PRIMITIVE Z ERRORS gt VARIANCE DATA after processing when FORM SIMPLE Z ERRORS gt VARIANCE after processing when FORM PRIMITIVE Z QUALITY gt QUALITY QUALITY must be BYTE array see Bad pixel handling below gt QUALITY BADBITS 255 Z LABEL gt LABEL Z UNITS gt UNITS Z IMAGINARY gt DATA_ARRAY IMAGINARY_DATA Z MAGFLAG gt MORE FIGARO MAGFLAG Z RANGE gt MORE FIGARO RANGE Z XXXX gt MORE FIGARO Z xxxx X DATA gt AXIS 1 DATA_ARRAY X ERRORS gt AXIS 1 VARIANCE after processing X WIDTH gt _ AXIS 1 WIDTH X LABEL gt AXIS 1 LABEL X UNITS gt AXIS 1 UNITS X LOG gt _ AXIS 1 MORE FIGARO LOG
24. the FITS file fxread m42 fit DATA HEADER Determine the size of the image SIZEX fxpar header NAXIS1 SIZEY fxpar header NAXIS2 Find the data type being read DTYPE fxpar header BITPIX Scale the image for display IMAGE congrid DATA SIZEX SIZEY INTERP window 0 xsize SIZEX ysize SIZEY Display the image TVSCL IMAGE As can be seen above various values contained within the FITS header of the original can be obtained using the FXPAR procedure You should bear in mind that a number of other procedures such as IEEE_TO_HOST and GET_DATE from the Astronomy Users Library are also needed by IDL when compiling this code Consequently it is essential that the whole library should be obtained from the archive SUN 55 31 Specifications of CONVERT IDL Procedures 96 97 READ_NDF SUN 55 31 Specifications of CONVERT IDL Procedures READ_NDF Convert a Starlink NDF to an IDL array Description This IDL function will convert a Starlink NDF file of up to seven dimensions to an IDL array of an appropriate type and shape in the NDF may be converted to specific values in the IDL array If NDF on the fly conversion has been activated the given filename may refer to a file of a different data format which is to be converted Usage Result READ_NDF Ndf_name Bad_value COMPONENT Comp_name Arguments Ndf_name A string expression specifying name of the NDF to be read Bad_
25. the new AST SpecFrame functionality allowing translation between spectral frames without re running SPECX2NDF The SPECTRUM parameter and associated parameters SOR DOPPLER are no longer required since they can be changed after conversion using WCSATTRIB application Scripts using SPECX2NDF may need modification In addition to dealing with map files SPECX2NDF has now been extended to deal with SPECX data files each spectrum in the file is translated to an NDF spectrum in the output HDS container file FITS2NDF supports INES archive IUE spectra Improved propagation of existing world co ordinate system WCS headers in NDF2FITS partially from improvements to the AST subroutine library For example long slit spectra with a three dimensional WCS but stored in a two dimensional image retain their three dimensional WCS headers Comments are preserved where values have not changed significantly The references to the old VMS only tasks have been removed from the documentation because the residual VMS service no longer exists E 5 1 Release Notes V1 5 4 Added IRAF compatibility libs for Linux systems CONVERT should now build on any ix86 Linux platform E 5 2 Release Notes V1 5 5 Added FITS AIPS and FITS CLASS encodings to FITSZNDF and NDF2FITS Clarified the description of JUNF2NDF parameter TYPE so that it is clear that the type given should also be of the input data not just the output NDF SPECX2NDF now creates NDF fi
26. the north ern hemisphere are positive The default corresponds to the latitude of the JCMT 19 49 33 LONGITUDE LITERAL Read The geodetic geographic longitude of the telescope where the observation was made The value should be specified in sexagesimal degrees with a colon to separate the degrees minutes and seconds and no embedded spaces Following the SUN 55 31 Specifications of CONVERT Applications 84 SPECX2NDF usual geographic convention longitudes west of Greenwich are positive The default corresponds to the longitude of the JCMT 155 28 47 OUT NDF Write The name of the output NDF containing the data cube or spectra written by the application The file extension sdf should not be included since it is appended automatically by the application SYSTEM LITERAL Read Celestial co ordinate system for output cube SPECX files do not record the co ordinate system for any offsets The recognised options are as follows e AZ azimuth and elevation e GA galactic e RB B1950 e RD equatorial of date e RJ J2000 SYSTEM needs to be used to set manually the correct co ordinates for a map file RJ TELESCOPE LITERAL Read The name of the telescope where the observation was made This parameter is used to look up the geodetic geographical latitude and longitude of the telescope See the documentation of subroutine SLA_OBS in SUN 67 for a list of permitted values Alternat
27. to a TIFF file Converts an NDF to a sequential unformatted file z z Ji J 5 N Cc z 5 os SPECX2NDF Converts a SPECX map into a simple data cube or SPECX data files to individual spectra Converts an image in TIFF format to an NDF Converts a sequential unformatted file to an NDF Cc j z a N oS Z zZ ol o a 5 In addition there are FITS readers within SUN 95 see SUN 95 which will convert FITS files and tapes to NDFs These are more tolerant of almost FITS files but lack support for IMAGE and BINTABLE extensions procedures for handling NDFs and other methods of converting NDFs to IDL format are described in Appendix B of this document 3 SUN 55 31 Introduction Starting up the CONVERT package will also set up defaults for the facilities described in Section to enable applications which use the NDF library to read and write most of the file formats handled by the CONVERT package and some others The various formats supported by CONVERT do not have one to one correspondence and there fore in general it is not possible to apply a forward and reverse conversion and finish with a duplicate of the initial data file This hysteresis is particularly likely when starting with an NDF since many simpler formats have no way of storing certain NDF data items like variance and axis widths However if you are dealing with a simple file containing just a data arra
28. z etc but a construct at the end of the name is assumed to be a sub file specifier to specify a particular FITS sub file to be converted See the description of an EXTABLE file above for allowed sub file specifiers but note that only a single keyword value pair is allowed here Note also that if a specifier contains a keyword value pair the name s must be enclosed in double quotes If you really want to have an a z type regular expression at the end of the filename you can put a null sub file specifier after it Indirection may occur through text files nested up to seven deep The indirection character is If extra prompt lines are required append the continuation character 27 FITS2NDF SUN 55 31 Specifications of CONVERT Applications to the end of the line Comments in the indirection file begin with the character gn OUT LITERAL Write The names for the output NDFs These may be enclosed in double quotes and specified as a list of comma separated names OR using modification elements to specify output NDF names based on the input filenames Indirection may be used if required The simplest modification element is the asterisk x which means call the output NDF files the same name without any directory specification as the corresponding input FITS file but with file extension sdf Other types of modification can also occur so OUT x would mean that the output files would have the same name as t
29. Applications CONVERT ASCII2NDF KAPPA TTRANDAT FIGARO ASCIN and ASCOUT Implementation Status e All non complex numeric data types are supported e The value of bad pixels is not written to a FITS like header record with keyword BLANK 53 NDF2DA SUN 55 31 Specifications of CONVERT Applications NDF2DA Converts an NDF to a direct access unformatted file Description This application converts an NDF to a direct access unformatted file which is equivalent to fixed length records or a data stream suitable for reading by C routines Only one of the array components may be copied to the output file Usage ndf2da in out comp noperec Parameters COMP LITERAL Read The NDF component to be copied It may be Data Quality or Variance Data IN NDF Read Input NDF data structure The suggested default is the current NDF if one exists otherwise it is the current value NOPEREC _INTEGER Read The number of data values per record of the output file It must be positive The suggested default is the current value The first dimension of the NDF OUT FILENAME Write Name of the output direct access unformatted file Examples ndf2da cluster cluster dat This copies the data array of the NDF called cluster to a direct access unformat ted file called cluster dat The number of data values per record is equal to the size of the first dimension of the NDF ndf2da cluster cluster dat v Th
30. CTURE The new data types are as follows Extension Name Data Type IRCAM GENERAL IRCAM_GENERAL IRCAM GENERAL INSTRUMENT IRCAM_INSTRUM IRCAM GENERAL ID IRCAM_ID IRCAM GENERAL TELESCOPE IRCAM_TELESCOPE e Upon completion the number of observations successfully converted to NDFs is reported Bad pixel Handling Elements of the data array equal to the IRCAM component OBS DATA_BLANK are replaced by the standard bad value Implementation Status e The data array in the NDF is in the primitive form e The application aborts if the data array chosen by parameter CONFIG does not exist in the observation SUN 55 31 Specifications of CONVERT Applications 48 MTFITS2NDF MTFITS2NDF Converts FITS magnetic tape files into NDFs Description This application converts files from a FITS tape into NDFs by using shell commands mt and dd to position the tape and convert the selected tape files into FITS disk files and then using FITSZNDF to produce the NDFs The intermediate FITS files may be saved Usage mtfits2ndf in out block n of fits_file lt fits2ndf_pars gt Parameters BLOCK _INTEGER Read The FITS blocking factor i e the block size on the tape is this value multiplied by the standard FITS block size The suggested default is 10 IN DEVICE Read The name of a tape device For correct tape positioning a no rewind device must be used The device name may have file specifiers appended separated by
31. DF It can have one of the following configu ration values e STARE the image of the object or sky e CHOP the chopped image of the sky e KTCSTARE the electronic pedestal or bias associated with the stare image of the object or sky e KTCCHOP the electronic pedestal or bias associated with the chopped image of the sky Note that at the time of writing chopping has not been implemented for IRCAM For practical purposes CONFIG STARE should be used The suggested default is the current value STARE FMTCNV _LOGICAL Read This specifies whether or not format conversion may occur If FMTCNV is FALSE the data type of the data array in the NDF will be the same as that in the IRCAM file and there is no scale factor and offset applied If FMTCNV is TRUE whenever the IRCAM observation has non null scale and offset values the observation data array will be converted to type REAL in the NDF and the scale and offset applied to the input data values to give the true data values A null scale factor is 1 and a null offset is 0 FALSE IN IRCAM Read The name of the input IRCAM file to convert to NDFs The suggested value is the current value OBS LITERAL Read A list of the observation numbers to be converted into NDFs Observations are numbered consecutively from 1 up to the actual number of observations in the IRCAM file Single observations or a set of adjacent observations may be specified e g ent
32. E LABEL or BUNIT respectively If the input NDF contains a FITS extension the FITS items may be written to the FITS like header with the following exceptions BITPIX is derived from the type of the NDF data array and so it is not copied from the NDF FITS extension x NAXIS and NAXISn are derived from the dimensions of the NDF data array as described above so these items are not copied from the NDF FITS extension x The TITLE LABEL and BUNIT descriptors are only copied if no TITLE LABEL and UNITS NDF components respectively have already been copied into these headers The CDELTn CRVALn CTYPEn CUNITn and CRTYPEn descriptors in the FITS extension are only copied if the input NDF contained no linear axis structures The standard order of the FITS keywords is preserved thus BITPIX NAXIS and AXISn appear immediately after the first card image which should be SIMPLE BSCALE and BZERO in a FITS extension are copied when BITPIX is positive i e the array is not floating point An extra header record with keyword UNSIGNED and logical value T is added when the array data type is one of the HDS unsigned integer types This is done because standard FITS does not support unsigned integers and allows in conjunction with BITPIX applications reading the unformatted file to determine the data type of the array The last header record card will be the standard FITS END e Other extensions are not propagated Related
33. EGER 11 _INT64 20 REAL 16 and DOUBLE 24 The record length is the product of the number of characters per value plus one for a delimiting space times the number of values per record given by parameter NOPEREC up to a maximum of 512 When FIXED is FALSE data values are packed as efficiently as possible within each record The length of each record is given by Parameter RECLEN FALSE IN NDF Read Input NDF data structure The suggested default is the current NDF if one exists otherwise it is the current value NOPEREC _INTEGER Read The number of data values per record of the output file when FIXED is TRUE It should be positive on UNIX platforms The suggested default is the current value or 8 when there is not one The upper limit is given by 512 divided by the number of characters per value plus 1 see Parameter FIXED OUT FILENAME Write Name of the output formatted Fortran file The file will normally have variable length records when there is a header but always fixed length records when there is no header 51 NDF2ASCII SUN 55 31 Specifications of CONVERT Applications RECLEN _INTEGER Read The maximum record length in bytes characters of the output file This has a maximum length of 512 for efficiency reasons and must be greater than 31 on UNIX systems The lower limit is further increased to 80 when there is a FITS header to be copied It is only used when FIXED is FALSE and will default to the cur
34. Fs and to limitations of the standard FITS header Related Applications CONVERT INDE2UNE SUN 55 31 Handling NDFs in IDL 92 B Handling NDFs in IDL B 1 The Easy Way Note that this method cannot be used with the 64 bit Solaris version of IDL use 4 idl 32 function READ_NDFiis available to convert a component of an NDF to an IDL array and WRITE_NDF IDL procedure WRITE_NDF will create an NDF component from an IDL array So for example IDL gt tv read_ndf comwest will display the data array of the NDF comwest sdf using the IDL command TV and IDL gt write_ndf field stars will create an NDF stars sdf of a suitable type and size and write the IDL array field to its DATA_ARRAY component IDL gt write_ndf q stars QUALITY will write the IDL array q to the QUALITY component of an existing NDF stars sdf Both READ_NDF and WRITE_NDF can take special action on bad values For a full description of their arguments see Appendix C Complete structures can be handled by function HDS2IDL and procedure DL2HDS So for example IDL gt comwest hds2id1 comwest Loaded DLM HDS2IDL IDL gt help comwest str Structure lt 40071208 gt 5 tags length 262184 refs 1 HDSSTRUCTYPE STRING gt IMAGE TITLE STRING Comet West low resolution DATA_ARRAY FLOAT Array 256 256 DATA_MIN FLOAT 3 89062 DATA_MAX FLOAT 245 937 IDL gt tv comwest data_array will displ
35. GIF2NDF NDF2TIFF 73 NDF2IRAF SUN 55 31 Specifications of CONVERT Applications NDF2IRAF Converts an NDF to an IRAF image Description This application converts an to an IRAF image See the Notes for details of the conversion Usage ndf2iraf in out fillbad Parameters IN NDF Read The input NDF data structure The suggested default is the current NDF if one exists otherwise it is the current value FILLBAD _REAL Read The value used to replace bad pixels in the NDF s data array before it is copied to the IRAF file A null value means no replacements are to be made This parameter is ignored if there are no bad values 0 OUT LITERAL Write The name of the output IRAF image Two files are produced with the same name but different extensions The pix file contains the data array and imh is the associated header file that may contain a copy of the NDF s FITS extension The suggested default is the current value PROFITS LOGICAL Read If TRUE the contents of the FITS extension of the NDF are merged with the header information derived from the standard NDF components See the Notes for details of the merger TRUE PROHIS __LOGICAL Read If TRUE any NDF history records are written to the primary FITS header as HISTORY cards These follow the mandatory headers and any merged FITS extension headers see parameter PROFITS TRUE Examples ndf2iraf abellii9 a119 Converts an NDF called
36. ICAL HDS components become IDL LONG components with LOGICAL_ prefixed to their name Any IDL byte integer or longword structure component must have this name convention if it is to be converted to an HDS __LOGICAL component by DL2HDS e IDL strings created from HDS CHAR components will have trailing spaces removed so there is no way to determine the size of the original HDS component 103 ADS2IDL SUN 55 31 Specifications of CONVERT IDL Procedures e HDS types _BYTE and _UWORD become IDL components indistinguishable from components produced from HDS types WORD and _INTEGER so if they are converted back to HDS by IDL2HDs their HDS type will have changed e Inan IDL array of structures each element must be exactly the same structure For HDS this is not the case therefore an HDS array of structures NAME will become an IDL structure NAME with component HDSSTRUCTYPE set to TYPE n m where TYPE is the type of the HDS array of structures and n m etc are the dimensions and components NAME_i_j etc where NAME_i_j etc are structures one for each element of the HDS array of structures Examples IDL gt data_struct hds2idl my_file Assuming my_file sdf is an HDS file this creates an IDL structure correspond ing to it Deficiencies e It is not possible to obtain an identical structure in all cases see Notes e Complex values are not handled Related Applications CONVERT IDL2HDS SUN 55 31
37. IFF file All smaller array values are also set to 0 when LOW is less than HIGH otherwise all array values greater than LOW are set to 0 The dynamic default is the minimum data value There is an efficiency gain when both LOW and HIGH are given on the command line because the extreme values need not be computed The lowest data value is suggested in prompts MSG_FILTER LITERAL Read The output message filtering level QUIET NORMAL or VERBOSE If set to verbose the scaling limits used will be displayed NORMAL 71 NDF2GIF SUN 55 31 Specifications of CONVERT Applications NUMBIN _INTEGER Read Only used if SCALE is Percentiles The number of histogram bins used to compute percentiles for scaling Percentiles mode 2048 PERCENTILES 2 _REAL Read Only required if SCALE is Percentiles The percentiles that define the scaling limits For example 25 75 would scale between the quartile values SCALE LITERAL Read The type of scaling to be applied to the array The options which may be abbreviated to an unambiguous string and are case insensitive are described below e Range The image is scaled between the minimum and maximum data values This is the default e Faint The image is scaled from the mean minus one standard deviation to the mean plus seven standard deviations e Percentiles The image is scaled between the values corresponding to two percentiles e Scale You define the upper and lo
38. IXi and CDi_j and is the system commonly used by IRAF It is described in the document World Coordinate Systems Rep resentations Within the FITS Format by by R J Hanisch and D G Wells 1988 available by ftp from fits cv nrao edu fits documents wces wcs88 ps Z 65 NDF2FITS SUN 55 31 Specifications of CONVERT Applications FITS WCS This is the FITS standard WCS encoding scheme described in the paper Representation of celestial coordinates in FITS http www atnf csiro au people mcalabre WCS It is very similar to FITS IRAF but supports a wider range of projections and co ordinate systems FITS WCS CD This is the same as FITS WCS except that the scaling and ro tation of the data array is described by a CD matrix instead of a PC matrix with associated CDELT values in a previous now superseded draft of the above FITS world co ordinate system paper by E W Greisen and M Calabretta FITS AIPS This uses conventions described in the document Non linear Coor dinate Systems in AIPS by Eric W Greisen revised 9th September 1994 available by ftp from fits cv nrao edu fits documents wcs aips27 ps Z It is currently em ployed by the AIPS data analysis facility amongst others so its use will facilitate data exchange with AIPS This encoding uses CROTAi and CDELTi keywords to describe axis rotation and scaling FITS AIPS This is an extension to FITS AIPS which allows the use of a wider range of
39. If the file 256 it contains neither DSS nor native AST keywords then no WCS component will be created fits2ndf multifile fit extname im3 This will create an NDF multifile from the first FITS extension in file multifile fit whose EXTNAME keyword has the value im3 fits2ndf multifile fit multifile extable tablel This will create a series of NDFs in the container file multifile sdf according to the specifications in the EXTABLE format file tablet Notes Some sources of FITS files that require special conversion rules particularly because they use binary tables are recognised Details of the processing for these is given within topic Special Formats Two other special cases are when a particular sub file is specified by the IN parameter and when conversion is driven by an EXTABLE file The general rules for the conversion apply if the FITS file is not one of the Special Formats including one defined by an EXTABLE and Parameter CONTAINER is not TRUE The general rules are as follows e The primary data array of the FITS file becomes the NDF s data array There is an option using Parameter FMTCNV to convert integer data to floating point using the values of FITS keywords BSCALE and BZERO e Any integer array elements with value equal to the FITS keyword BLANK become bad values in the NDF data array Likewise any floating point data set to an IEEE 31 FITS2NDF SUN 55 31 Specifications of CONVERT Applicat
40. It appears regardless of whether or not there are bad values actually present in the array this is for the same efficiency reasons as before The END card terminates the FITS header SUN 55 31 Specifications of CONVERT Applications 64 NDF2FITS HISTORY HISTORY headers are propagated from the FITS airlock when PROFITS is TRUE and from the NDF history component when PROHIS is TRUE DATASUM and CHECKSUM data integrity keywords are written when Pa rameter CHECKSUM is TRUE replacing any existing values When Parameter CHECKSUM is FALSE and PROFITS is TRUE any existing values inherited from the FITS airlock are removed to prevent storage of invalid checksums relating to another data file See also the sections Provenance and World Co ordinate Systems for details of headers used to describe the PROVENANCE extension and WCS information respectively Extension information may be transferred to the FITS file when PROEXTS is TRUE The whole hierarchy of extensions is propagated in order This includes substructures and arrays of extensions and substructures However at present any extension structure containing only substructures is not propagated itself as zero column tables are not permitted although its substructures may be converted Each extension or substructure creates a one row binary table where the columns of the table correspond to the primitive non structure components The name of each column is the compone
41. LITY component must comprise unsigned bytes equivalent to TYPE _UBYTE to be a valid NDF The suggested default is the current value _REAL Examples da2ndf ngc253 dat ngc253 shape 100 60 noperec 8 This copies a data array from the direct access file ngc253 dat to the NDF called SUN 55 31 Specifications of CONVERT Applications 18 DA2NDF ngc253 The NDF is two dimensional 100 elements in x by 60 in y Its data array has type _REAL The data records each have 8 real values da2ndf ngc253q dat ngc253 q 100 100 60 This copies a quality array from the direct access file ngc253q dat to an existing NDF called ngc253 such as created in the first example The NDF is two dimensional 100 elements in x by 60 in y Its data array has type UBYTE The data records each have 100 unsigned byte values da2ndf type _uword in ngc253 dat out ngc253 This copies a data array from the direct access file ngc253 dat to the NDF called ngc253 The NDF has the current shape and data type is unsigned word The current number of values per record is used Notes The details of the conversion are as follows e the direct access file s array is written to the NDF array as selected by COMP When the NDF is being modified the shape of the new component must match that of the NDE This enables more than one array input file to be used to form an NDF Note that the data array must be created first to make a valid NDF Indeed the applicati
42. M NDF2PGM Converts an NDF to a PBMPLUS style PGM format file Description This application converts an to a PBMPLUS PGM format file The programme first finds the brightest and darkest pixel values in the image It then uses these to determine suitable scaling factors to convert the image into an 8 bit representation These are then output to a simple greyscale PBMPLUS PGM file Usage ndf2pgm in out Parameters IN NDF Read The name of the input NDF data structure without the sdf extension The sug gested default is the current NDF if one exists otherwise it is the current value OUT _CHAR Read The name of the PGM file be generated The pgm name extension is added to any output filename that does not contain it Examples ndf2pgm old new This converts the NDF called old in file old sdf to the PGM file new pgm ndf2pgm in spectre out spectre pgm This converts the NDF called spectre in file spectre sdf to the PGM file spectre pgm Notes This programme was written for diagnostic purposes and is included just in case someone finds it useful Implementation Status in the data array are replaced with zero in the output PGM file 77 NDF2TIFF SUN 55 31 Specifications of CONVERT Applications NDEFE2TIFF Converts an NDF to an 8 bit TIFF 6 0 format file Description This application converts an to a Tag Image File Format TIFF One or two dimensional arrays can be handled and various met
43. NVERT package application NDF2ASCH and then read the resulting file with IDL The steps taken might be something like ndf2ascii in imagein out fileout This will create a file fileout containing the DATA component of the NDF called imagein If you want to store the VARIANCE or QUALITY components you would use comp v or comp q respectively as additional parameters You can then employ a simple IDL batch file such as Create IMAGE an 339x244 single precision floating point array IMAGE FLTARR 339 244 Open the existing NDF2ASCII file fileout for read only access OPENR UNIT fileout GET_LUN Read formatted input from the specified file unit and place in the variable IMAGE READF UNIT IMAGE Closes the file unit used CLOSE UNIT Display the image after suitable scaling TVSCL IMAGE The above example assumes image dimensions of 339x244 pixels If you are in any doubt as to the dimensions of your image you can determine them using the KAPPA application NDFTRACE SUN 55 31 Handling NDFs in IDL 94 B 2 Other Methods One advantage of this route is that the ASCII data can instead be read directly into byte integer or double precision arrays structures by simply substituting INTARR DBLARR or BYTARR for FLTARR Clearly it should be remembered that attempting to represent floating point values within a byte array will not work properly whereas a double precision array will accommodate double precisi
44. RAL Read The list of array components to attempt to transfer to each FITS file The acceptable values are D for the main data array V for variance Q for quality or any permutation thereof The special value A means all components i e COMP DVQ Thus COMP VD requests that both the data array and variance are to be converted if present During processing at least one if not all of the requested components must be present otherwise an error is reported and processing turns to the next input NDF If the DATA component is in the list it will always be processed first into the FITS primary array The order of the variance and quality in COMP decides the order they will appear in the FITS file The choice of COMP may affect automatic quality masking See Quality Masking for the details COMP may be a list of comma separated values to be applied to each conversion in turn The list must be enclosed in double quotes An error results if more values than the number of input NDFs are supplied If too few are given the last value in the list is applied to the remainder of the NDFs thus a single value is applied to all the conversions The given values must be in the same order as that of the input NDEFs Indirection through a text file may be used If more than one line is required to enter the information at a prompt then type a at the end of each line where a continuation line is desired A CONTAINER _LOGICAL Read If TR
45. SUN 55 31 Starlink Project Starlink User Note 55 31 Malcolm J Currie G J Privett A J Chipperfield D S Berry A C Davenhall 2014 July 9 Copyright 2014 Science and Technology Research Council CONVERT A Format conversion Package Version 1 8 User s Manual SUN 55 31 Abstract ii Abstract The CONVERT package contains utilities for converting data files between Starlink s Extensible n dimensional Data Format NDF which is used by most Starlink applications and a number of other common data formats Using these utilities astronomers can process their data selecting the best applications from a variety of Starlink or other packages Most of the CONVERT utilities may be run from the shell or ICL in the normal way or invoked automatically by the NDF library s on the fly data conversion system but there are also procedures for handling NDFs from within IDL Copyright 2014 Science and Technology Research Council Contents 1 Introduction 1 Starting CONVERT from the UNIX shell 2 Starting CONVERT from ICL 2 3 Issuing CONVERT Commands 2 4 Obtaining Help 2 5 Hypertext Help 3 Automatic Format Conversion with the NDF Library 3 1 The Default Conversion Commands N 4 Automatic HISTORY Creation 5 Acknowledgments A Specifications of CONVERT Applications A 1 Explanatory Notes ASCIPNDF AST2NDE DA2NDF eapo try duai ee ee DST2NDEF BITS2NDE eggs see eee eB a a a
46. See the FITS2NDF description for details 49 MTFITS2NDF SUN 55 31 Specifications of CONVERT Applications Examples mtfits2ndf dev nst0O 2 256 block 10 fmtcnv f This converts the second file on the tape on device dev nstO to an NDF called 256 The FITS blocking factor of the tape is 10 As a result of the parameters passed to FITS2NDF the data type of the NDF s data array matches that of the FITS primary data array a FITS extension is created in 256 and FITS sub files are propagated to NDF extensions mtfits2ndf dev nstO block 1 of ral256_ fit Will convert each file on the tape on device dev nst0O with a blocking factor of 1 to FITS disk files named ral1256_ fit where is replaced by each tape file number The FITS files will be converted to NDFs named ral1256_ and retained mtfits2ndf The user is prompted for the input device the output NDF name and the FITS blocking factor All other parameters are defaulted Referd e4 Office of Standards and Technology 1997 A User s Guide for the Flexible Image Transport System FITS Version 4 0 NASA Office of Standards and Technology 1999 Definition of the Flexible Image Transport System FITS Deficiencies e Facilities for naming multiple output files are limited e The command is not available from ICL nor as an option in the automatic on the fly conversion system e Extensions within a FITS file may not be specified However it is possible to
47. Specifications of CONVERT IDL Procedures 104 IDL2HDS IDL2HDS Convert an IDL variable to a Starlink HDS file Description This IDL procedure will create a Starlink HDS file corresponding to the IDL variable which may be a scalar array or structure Usage IDL gt id1l2hds IDL_struct filename Arguments IDL_struct The IDL variable to be written filename A string expression specifying name of the HDS file to be written The HDS structure is not necessarily identical to the IDL structure see Notes Notes e Type correspondence is as follows floating gt _REAL double precision gt _DOUBLE byte gt _UBYTE unless _LOGICAL see below integer gt _WORD unless _LOGICAL see below longword integer gt _INTEGER unless LOGICAL see below string gt _CHAR IDL string size e Each HDS structure will have a type as defined by the HDSSTRUCTYPE component of the IDL structure If there is no such component the HDS type is blank e Byte integer or longword integer components which have LOGICAL_ prefixed to their name will be converted to LLOGICAL HDS components and the prefix will be removed from the name e IDL strings will be converted into HDS CHAR components whose size is the size of the IDL string If a size greater than the used length is required the IDL string must be padded with blanks e HDS arrays of structures will be created from IDL structures having duced from HDS arrays of structures by HDS2IDL
48. TAB algorithm as defined in the FITS WCS Paper II Examples where such a table might be present in the WCS include wavelengths of pre scrunched spectra and the presence of distortions that prevent co ordinates being defined by analytical expressions Since many FITS readers are yet to support the TAB algorithm which uses a FITS binary table extension to store the co ordinates this parameter permits this facility to be disabled TRUE AXISORDER LITERAL Read Specifies the order of WCS axes within the output FITS header It can be either null Copy or a space separated list of axis symbols case insensitive If it is null the order is determined automatically so that the ith WCS axis is the WCS axis that is most nearly parallel to the ith pixel axis If it is Copy the ith WCS axis in the FITS header is the ith WCS axis in the NDF s current WCS Frame Otherwise the string must be a space separated list of axis symbols that gives the order for the WCS axes An error is reported if the list does not contain any of the axis symbols present in the current WCS Frame but no error is reported if the list also contains other symbols BITPIX LITERAL Read The FITS bits per pixel BITPIX value for each conversion This specifies the data type of the output FITS file Permitted values are 8 for unsigned byte 16 for signed word 32 for integer 64 for 64 bit integer 32 for real 64 for double precision There are three other specia
49. TS_LHEADER containing the FITS header as an array of type _CHAR 80 is created if PROFITS is FALSE no component is created Binary and ASCII tables become components of type TABLE formatted as in the general rules under Notes below FALSE ENCODINGS LITERAL Read Determines which FITS keywords should be used to define the world co ordinate 23 FITS2NDF SUN 55 31 Specifications of CONVERT Applications systems to be stored in the NDF s WCS component This parameter is only relevant when WCSCOMP is WCS or Both The allowed values case insensitive are FITS IRAF This uses keywords CRVALi CRPIXi CDi_j and is the system commonly used by IRAF It is described in the document World Coordinate Systems Representations Within the FITS Format by R J Hanisch and D G Wells 1988 available by ftp from fits cv nrao edu fits documents wcs wcs88 ps Z FITS WCS This is the FITS standard WCS encoding scheme described in the paper Representation of celestial coordinates in FITS http www atnf csiro au people mcalabre WCS Itis very similar to FITS IRAF but supports a wider range of projections and co ordinate systems described in a previous now superseded draft of the above FITS world co ordinate system paper by E W Greisen and M Calabretta FITS AIPS This uses conventions described in the document Non linear Coordinate Systems in AIPS by Eric W Greisen revised 9th September 1994 available by
50. UE the supplied IN files are any multi NDF HDS container files in which the NDEFs reside as top level components This option is primarily intended to support the UKIRT format where the NDFs are named In n gt 1 and one named HEADER containing global metadata in its FITS airlock The In NDFs may also contain FITS airlocks storing metadata pertinent to that NDF such as observation times The individual NDFs often represent separate integrations nodded along a slit or spatially 59 NDF2FITS SUN 55 31 Specifications of CONVERT Applications Note that this is not a group so a single value applies to all the supplied input files FALSE DUPLEX _LOGICAL Read This qualifies the effect of PROFITS TRUE DUPLEX FALSE means that the airlock headers only appear with the primary array DUPLEX TRUE propagates the FITS airlock headers for other array components of the NDF FALSE ENCODING LITERAL Read Controls the FITS keywords which will be used to encode the World Co ordinate System WCS information within the FITS header The value supplied should be one of the encodings listed in the World Co ordinate Systems section below In addition the value Auto may also be supplied in which case a suitable default encoding is chosen based on the contents of the NDF s FITS extension and WCS component Auto IN LITERAL Read The names of the NDFs to be converted into FITS format It may be a list of NDF names or direction spe
51. X XXXX gt AXIS 1 MORE FIGARO xxxx Similarly for Y T U V or W structures which are renamed to AXIS 2 AXIS 6 in the NDF OBS OBJECT gt TITLE OBS SECZ gt MORE FIGARO SECZ OBS TIME gt MORE FIGARO TIME OBS xxxx gt MORE FIGARO OBS xxxx FITS xxxx gt MORE FITS xxxx into value part of the string COMMENTS xxxx gt MORE FITS n into comment part of the string FITS xxxx DATA gt MORE FITS n into value part of the string FITS xxxx DESCRIPTION MORE FITS n into comment part of the string FITS xxxx yyyy gt MORE FITS n into blank keyword comment con taining yyyy value MORE xxxx MORE xxxx TABLE gt MORE FIGARO TABLE XXXX MORE FIGARO xxxx Axis arrays with dimensionality greater than one are not supported by the NDF Therefore if the application encounters such an axis array it processes the array using the following rules rather than those given above 21 DST2NDF SUN 55 31 Specifications of CONVERT Applications Figaro file NDF Comments X DATA AXIS 1 MORE FIGARO DATA_ARRAY AXIS 1 DATA_ARRAY is filled with pixel co ordinates X ERRORS AXIS 1 MORE FIGARO VARIANCE after processing X WIDTH _ AXIS 1 MORE FIGARO WIDTH In addition to creating a blank keyword NDF FITS extension header for each compo nent of a non standard DST FITS structure FITS xxxx yyyy where yyyy is not DATA or DESCRIPTION this set of relate
52. _MH extension NOISE NET columns except BACKGROUND and RIPPLE are NDFs each com 14 17 prising a data array label units and wavelength axis SUN 55 31 Specifications of CONVERT Applications 34 FITS2NDF It may be possible to evaluate an approximate error array for the absolutely calibrated data ABS_CAL by multiplying the NOISE by the ratio ABS_CAL NET for each element The Chebyshev coefficients limits and scale factor in columns 14 to 17 are omitted as the evaluated background fit is propagated in BACKGROUND e IUEINES reduced spectra This generates a single 1 dimensional NDF Only the most significant 8 bits of the quality flags are transferred to the NDF The primary headers may be written to the standard FITS airlock extension when PROFITS is TRUE The conversion from binary table columns and headers to NDF objects is as follows WAVELENGTH Start wavelength axis label and units FLUX Data array label units bad pixel flag SIGMA Data error array QUALITY Quality array e CAM auto analysis CMAP CMOS The CAM auto analysis FITS products have a binary table using the Green Bank convention where rows of the table represent a series of observations and each row is equivalent to a normal simple header and data unit Thus most of the columns have the same names as the standard FITS keywords If there is only one observation a normal NDF is produced if there are more than one the HDS conta
53. abell119 into the IRAF image comprising the pixel file a119 pix and the header file a119 imh If there are any bad values present they are copied verbatim to the IRAF image ndf2iraf abell119 a119 noprohis As the previous example except that NDF HISTORY records are not transferred to the headers in a119 imh SUN 55 31 Specifications of CONVERT Applications 74 NDF2IRAF ndf2iraf qsospe qsospe fillbad 0 Converts the NDF called qsospe to an IRAF image comprising the pixel file qsospe imh and the header file qsospe pix Any bad values in the data array are replaced by zero ndf2iraf qsospe qsospe fillbad 0 profits f As the previous example except that any FITS airlock information in the NDF are not transferred to the headers in qsospe imh Notes The rules for the conversion are as follows The NDF data array is copied to the pix file Ancillary information listed below is written to the imh header file in FITS like headers The IRAF Mini World Co ordinate System MWCS is used to record axis informa tion whenever one of the following criteria is satisfied 1 the dataset has some linear axes system world 2 the dataset is one dimensional with a non linear axis or is two dimensional with the first axis non linear and the second being some aperture number or index system multispec 3 the dataset has a linear spectral dispersion axis along the first dimension and all other dimensions are pixel indice
54. and line More often you ll enter the command name and just some of the parameters and be prompted for the rest Examples give command lines as accepted by the tasks themselves From the UNIX shell metacharacters notably and must be escaped or enclosed in single quotes For example ascii2ndf ngc253q dat ngc253 q shape 100 60 fits2ndf abc fit def fits fgh ijk fmtcnv F T noproexts SUN 55 31 Specifications of CONVERT Applications FORMAT In out Utility FITS FIGARO IRAF STREAM UNFORMATTED UNFO ASCII TEXT GIF TIFF GASP COMPRESSED GZIP in out in out in out in out in out in out in out in out in out in out in out in out in out Non default parameters Variable IRAF2NDF RAF DA2NDF NDF2DA UNF2NDF NDF2UNF UNF2NDF NDF2UNF ASCII2NDF NDF2ASCII ASCII2NDF NDF2ASCII GIF2NDF NDF2GIF TIFF2NDF NDF2TIFF GASP2NDF NDF2GASP Z 4 gt uncompress compress gzip gunzip bitpix 1 proexts t noperec fits t noperec fits t fits f noperec J fits f fits t fits t reclen 80 fits f ay fits f reclen 80 fillbad 0 Table 2 Conversion Commands 12 13 ASCIIZNDF SUN 55 31 Specifications of CONVERT Applications ASCII2NDF Converts a text file to an NDF Description This application converts a text file to an NDF Only one of the array components may be created f
55. are set to 0 The dynamic default is the minimum data value There is an efficiency gain when both LOW and HIGH are given on the command line because the extreme values need not be computed The lowest data value is suggested in prompts MSG FILTER LITERAL Read The output message filtering level QUIET NORMAL or VERBOSE If set to verbose the scaling limits used will be displayed NORMAL NUMBIN _INTEGER Read The number of histogram bins used to compute percentiles for scaling It is only used if SCALE is Percentiles 2048 SUN 55 31 Specifications of CONVERT Applications 78 NDF2TIFF OUT _CHAR Read The name of the TIFF file to be generated A tif name extension is added to any output filename that does not contain it Any existing file with the same name will be overwritten PERCENTILES 2 _REAL Read The percentiles that define the scaling limits For example 25 75 would scale between the quartile values It is only required if SCALE is Percentiles SCALE LITERAL Read The type of scaling to be applied to the array The options which may be abbreviated to an unambiguous string and are case insensitive are described below e Range The image is scaled between the minimum and maximum data values This is the default e Faint The image is scaled from the mean minus one standard deviation to the mean plus seven standard deviations e Percentiles The image is scaled between the values corr
56. atching pair of square brackets terminates the description The content between the brackets mean Empty brackets means that the default is created dynamically by the application and may depend on the values of other parameters Therefore the default cannot be given explicitly As above but there are two default values that are created dynamically default Occasionally a description of the default is given in normal type default If the brackets contain a value in teletype fount this is the explicit default value There is also a Usage entry This shows how the application is invoked from the command line It lists the positional parameters in order followed by any prompted keyword parameters using a KEYWORD syntax Defaulted keyword parameters do not appear Positional parameters that are normally defaulted are indicated by being enclosed in square brackets Keyword i e not positional parameters are needed where the number of parameters are large and usually occur because they depend on the value of another parameter An example should clarify ndf2ascii in out comp reclen noperec IN OUT COMP and RECLEN are all positional parameters Only IN and OUT would be prompted if not given on the command line The remaining parameter NOPEREC depends on the value of another parameter it is FIXED and will be prompted for when FIXED is TRUE The Examples section shows how to run the application from the comm
57. ated Applications CONVERT IRAF2NDF Pitfalls The IMFORT routines refuse to overwrite an IRAF image if an image with the same name exists The application then aborts Some of the routines required for accessing the IRAF header image are written in SPP Macros are used to find the start of the header line section this constitutes an Interface violation as these macros are not part of the IMFORT interface specification It is possible that these may be changed in the future so beware References IRAF User Handbook Volume 1A A User s Guide to FORTRAN Programming in IRAF the IMFORT Interface by Doug Tody Implementation Status e Only handles one two and three dimensional NDFs e Of the NDF s array components only the data array may be copied e The IRAF image produced has type SIGNED WORD or REAL dependent of the type of the NDF s data array The IRAF IMFORT FORTRAN subroutine library only supports these data types For BYTE UBYTE and _WORD data arrays the IRAF image will have type SIGNED WORD for all other data types of the NDF data array a REAL IRAF image is made The pixel type of the image can be changed from within IRAF using the chpixtype task in the images package e Bad values may arise due to type conversion These too are substituted by the non null value of FILLBAD e See Release Notes for IRAF Version compatibility SUN 55 31 Specifications of CONVERT Applications 76 NDF2PG
58. ations of CONVERT Applications 80 NDF2UNF NDF2UNF Converts an NDF to a sequential unformatted file Description This application converts an NDF to a sequential unformatted Fortran file Only one of the array components may be copied to the output file Preceding the data there is an optional header consisting of either the FITS extension with the values of certain keywords replaced by information derived from the NDF or a minimal FITS header also derived from the NDF Usage ndf2unf in out comp noperec Parameters COMP LITERAL Read The NDF component to be copied It may be Data Quality or Variance Data FITS LOGICAL Read If TRUE any FITS extension is written to start of the output file unless there is no extension whereupon a minimal FITS header is written to the unformatted file FALSE IN NDF Read Input NDF data structure The suggested default is the current NDF if one exists otherwise it is the current value NOPEREC _INTEGER Read The number of data values per record of the output file It must be positive The suggested default is the current value The first dimension of the NDF OUT FILENAME Write Name of the output sequential unformatted file The file will but always fixed length records when there is no header Examples ndf2unf cluster cluster dat This copies the data array of the NDF called cluster to an unformatted file called cluster dat The number of data values p
59. ay the same image as the READ_NDF example above but the other components of the NDF are also available in the IDL structure comwest so that IDL gt idl2hds comwest newcomwest will create a duplicate of comwest sdf in newcomwest sdf Exact duplication of the type and structure is not always possible see the routine descriptions for details When CONVERT is installed the converter procedures and routines are placed in CONVERT_DIR so to make them available to IDL that directory must be added to the IDL search paths IDL_PATH and IDL_DLM_PATH This will be done if the environment variable IDL_PATH has been set usually by sourcing the idl_setup script when you start the CONVERT package by typing 93 B 2 Other Methods SUN 55 31 Handling NDFs in IDL convert Note that convert must be run after sourcing the idl_setup script Note also that having started CONVERT the NDF library see SUN 33 which is ultimately used by READ_NDF and WRITE_NDEF will allow them but not HDS2IDL and IDL2HDS to do conversion see Section 3 of any files given as parameters This opens up the possibility of using almost any data format with IDL As an example IDL gt tv read_ndf moon imh will display the IRAF file moon imh B 2 Other Methods B 2 1 A simple route but rather slow The simplest route to use when generating data for IDL from NDFs is to create an ASCII copy of the NDF you are interested in using the CO
60. bbreviated Deficiencies No conversion of the given bad value to the appropriate type for the array will be at tempted instead an error will be reported Related Applications CONVERT WRITE_NDF 99 WRITE_NDF SUN 55 31 Specifications of CONVERT IDL Procedures WRITE_NDF Convert an IDL array to a Starlink NDF Description This IDL procedure will write an IDL array of up to seven dimensions to a Starlink NDF If NDF on the fly conversion has been activated the given filename may refer to a file of a different data format in which case the NDF is then automatically converted to the required file type Usage IDL gt write_ndf IDL_array Ndf_name Bad_value COMPONENT Comp_name Arguments IDL_array The IDL array to be converted This may be an array name or constant of up to seven dimensions The type of the NDF component created will depend on the type of the given array floating gt REAL double precision gt _DOUBLE byte gt _UBYTE integer gt _WORD longword integer gt _INTEGER No other types are allowed Ndf_name A string expression specifying name of the NDF to be written Bad_value Optional A value any occurrence of which in the IDL array is to be replaced by the appropriate PRIMDAT bad value in the NDF component If no such value is found the NDF bad pixel flag for the component is set FALSE The value must be the same type as the array Keywords COMPONENT Set this to a string ex
61. case insensitive is a character string specifying a trans formation to be applied to the FITS data before it is written into the NDF com ponent The code and preceding may be omitted in which case NONE no transformation is assumed Currently the only permitted code is NONE There may be more than one component specifier record for a given component the sub file specifiers will be concatenated A sub file specifier may not span records and only the transformation code specified by the last record for the component will be effective NDFNAMES records have the format 25 FITS2NDF SUN 55 31 Specifications of CONVERT Applications NDFNAMES name_list Where name_list is a list of names for the NDFs to be created one for each sub file set specified by the component specifier lines The names are separated by commas If any of the names are omitted the last name specified is assumed to be a root name to which an integer counter is to be added until a new name is found If no names are specified EXTN_SET is used as the root name For example NDFNAMES NDF SET_ would result in NDFs named NDF1 NDF2 SET_1 SET_2 etc up to the given number of sub file sets There may be multiple NDFNAMES records the names will be concatenated A name may not span records and a comma as the last non blank character indicates an omitted name If there is only one sub file set name_list may be in which case the NDF will be created at the top
62. cifications separated by commas and enclosed in double quotes NDF names may include wild cards Indirection may occur through text files nested up to seven deep The indirection character is If extra prompt lines are required append the continuation character to the end of the line Comments in the indirection file begin with the character NATIVE LOGICAL Read If a TRUE value is given for Parameter NATIVE then World Co ordinate System WCS information will be written to the FITS header in the form of a native encoding see World Co ordinate Systems below This will be in addition to the encoding specified using Parameter ENCODING and will usually result in two descriptions of the WCS information being stored in the FITS header unless ENCODING parameter produces a native encoding in which case only one native encoding is stored in the header Including a native encoding in the header will enable other AST based software such as FITS2NDF to reconstruct the full details of the WCS information The other non native encodings will usually result in some information being lost FALSE MERGE _LOGICAL Read Whether or not to merge the FITS airlocks headers of the header NDF of a UKIRT multi NDF container file with its sole data NDF into the primary header and data unit HDU This parameter is only used when CONTAINER is TRUE and when the container file only has two component NDFs one data NDF of arbit
63. contain a header section The NDF is two dimensional 100 elements in x by 60 in y Its data array has type UBYTE ascii2ndf ngc253 dat ngc253 fits This copies a data array from the text file ngc253 dat to the NDF called ngc253 The input file contains a FITS like header section which is copied to the FITS extension of the NDF The shape of the NDF is controlled by the mandatory FITS keywords NAXIS AXIS1 AXISn and the data type by keywords BITPIX and UNSIGNED ascii2ndf type _uword in ngc253 dat out ngc253 maxlen 4000 This copies a data array from the text file ngc253 dat to the NDF called ngc253 The input file does not contain a header section The NDF has the current shape and data type is unsigned word The maximum record length is 4000 bytes ascii2ndf spectrum ZZ skip 2 shape 200 This copies a data array from the text file spectrum to the NDF called ZZ The input file contains two header records that are ignored The NDF is one dimensional comprising 200 elements of type REAL ascii2ndf spectrum lis ZZ skip 1 fits This copies a data array from the text file spectrum lis to the NDF called ZZ The input file contains one header record that is ignored followed by a FITS like header section which is copied to the FITS extension of the NDF The shape of the NDF is controlled by the mandatory FITS keywords NAXIS AXIS1 AXIS and the data type by keywords BITPIX and UNSIGNED Notes The details of the conversion ar
64. container file u20040730_00675 sdf to new FITS file u20040730_00675 fit merging its I1 and HEADER structures into a single NDF before the conversion The output file has only one header and data unit SUN 55 31 Specifications of CONVERT Applications 62 NDF2FITS ndf2fits in c20011204_00016 out cgs4_16 fit container This converts the CGS4 container file c20011204_00016 sdf to the multiple extension FITS file cgs4_16 f it The primary HDU has the global metadata from the HEADER s FITS airlock The four integrations in I1 I2 I3 and 14 components of the container file are converted to FITS IMAGE sub files ndf2fits in huge out huge fits comp d bitpix n This converts the NDF called huge to the new FITS file called huge fits The data type of the FITS primary data array matches that of the NDF s scaled data array The scale and offset coefficients used to form the FITS array are also taken from the NDF s scaled array ndf2fits in huge out huge fits comp d bitpix 1 As the previous example except that the data type of the FITS primary data ar ray is that given by the BITPIX keyword in the FITS airlock of NDF huge and the scaling factors are determined Notes The rules for the conversion are as follows e The NDF main data array becomes the primary data array of the FITS file if it is in value of Parameter COMP otherwise the first array defined by Parameter COMP will become the primary data array A conversion from floatin
65. ct a bug in FITSZNDPF affecting the import of SMURF data containing VARIANCE or QUALITY that was formerly in an NDF E 5 14 Release Notes V1 5 17 The bash CONVERT initialisation script has been changed so that it now works from any Bourne compatible shell E 5 15 Release Notes V1 5 18 FITS2ZNDFirecognises the new Group heading in HISTORY headers that originally came from an exported NDF This lists all the NDFs stored within a GRP group used in an application Thus the original paragraph and indentation may be preserved after an NDF FITS NDF cycle NDEF2FITS allows three letter permutations for Parameter COMP There is now no automatic quality masking of data and variance whenever the quality array is exported to the FITS file too A new subsection of the NDF2FITS reference documentation explains this in more detail Removed default history recording in FITS2NDF s output NDF since you can control automatic history creation via the NDF_AUTO_HISTORY environment variable SUN 55 31 Release Notes 112 E 5 Release Notes V1 5 E 5 16 Release Notes V1 5 19 Propagate LABEL keyword to NDF label in FITS2NDF FITS2NDF can now recreate data that were formerly in a UKIRT_HDS container file NDF2FITS now recognises the modified data type of the SMURF extension It handles compo nent names that are too long to fit in a single EXTNAME header by creating an EXTNAMEF keyword that uses the Long string convention It a
66. ctra may be omitted for the positions at the corners of the grid SPECX map files are standard Starlink NDF HDS structures The principal array of the NDF is a two dimensional array of the grid positions The value of each element is either a pointer to the spectrum observed there in practice the number of the spectrum in the array where they are stored or a value indicating that a spectrum was not observed at this point In effect the SPECX map structure is an implementation of a sparse array SPECX2NDEF expands a SPECX map file into a simple three dimensional data cube again formatted as a standard NDF in which the first and second pixel axes corresponds to the spatial axes and the third axes correspond to the spectral axis The advantage of this approach is that the converted file can be examined with standard applications such as those in KAPPA see SUN 95 and easily imported into visualisation packages such as Data Explorer DX EN SC 2 When the output data cube is created the columns corresponding to the positions on the sky grid where spectra were not observed are filled with bad values sometimes called magic or null values to indicate that valid data are not available at these positions The standard Starlink bad value is used Because of the presence of these bad values the expanded cube is usually larger than the original map file The created NDF cube has a WCS component in which Axes 1 and 2 are RA and DEC and
67. d from the FITS data type to REAL or _DOUBLE in the NDF The special value FMTCNV Native is a variant of FALSE that in addition creates a scaled form of NDF array provided the array values are scaled through BSCALE and or BZERO keywords i e the keywords values are not the null 1 0 and 0 0 respectively This NDF scaled array contains the unscaled data values and the scale and offset The actual NDF data type for FMTCNV TRUE and the data type after applying the scale and offset for FATCNV NATIVE are both specified by Parameter TYPE However if TYPE is a blank string or null then the choice of floating point data type depends on the number of significant digits in the BOCALE and BZERO keywords FMTCNV may be a list of comma separated values enclosed in double quotes to be applied to each conversion in turn An error results if more values than the number of input FITS files are supplied If too few are given the last value in the list applied to all the conversions thus a single value is applied to all the input files If more than one line is required to enter the information at a prompt then place a at the end of each line where a continuation line is desired TRUE IN LITERAL Read The names of the FITS format files to be converted to NDFs It may be a list of file names or indirection specifications separated by commas and enclosed in double quotes FITS file names may include the regular expressions a
68. d headers are bracketed by blank lines and a comment containing the name of the structure i e xxxx Related Applications CONVERT NDEF2DST Bad pixel handling The QUALITY array is only copied if the bad pixel flag Z FLAGGED is FALSE or absent A simple NDF with the bad pixel flag set to FALSE meaning that there are no bad pixels present is created when Z FLAGGED is absent or false and FORM SIMPLE Implementation Status The maximum number of dimensions is 6 SUN 55 31 Specifications of CONVERT Applications 22 FITS2NDF FITS2NDF Converts FITS files into NDFs Description This application converts one or more files in the FITS format into NDFs It can process an arbitrary FITS file to produce an NDF using NDF extensions to store information conveyed in table and image components of the FITS file While no information is lost in many common cases this would prove inconvenient especially as no meaning is attached to the NDF extension components Therefore FITS2NDF recognises certain data products currently and 2dF and provides tailored conversions that map the FITS data better on to the NDF components For instance a FITS IMAGE extension storing data errors will have its data array transferred to the NDF s VARIANCE after being squared In addition FITS2NDF can restore NDFs converted to FITS by the sister taskINDF2FITS A more general facility is also provided to associate specified FITS extensions with NDF co
69. data or variance as bad values NDF2FITS uses this facility in exported data variance information provided the quality array is not transferred Thus if a QUALITY component is present in the input NDF the data and any variance arrays will not be masked whenever Parameter COMP s value is gt A or contains Q Special Formats In the general case NDF extensions excluding the FITS extension may be converted to one row binary tables in the FITS file when Parameter PROEXTS is TRUE This preserves the information but it may not be accessible to the recipient s FITS reader Therefore in some cases it is desirable to understand the meanings of certain NDF extensions and create standard FITS products for compatibility At present only one product is supported but others may be added as required e AAO 2dF Standard processing is used except for the 2dF FIBRES extension and its constituent structures The NDF may be restored from the created FITS file using FITS2NDE The FIBRES extension converts to the second binary table in the FITS file the NDF_CLASS extension appears in the first To propagate the OBJECT substructure NDF2FITS creates a binary table of constant width 224 bytes with one row per fibre The total number of rows is obtained from component NUM_FIBRES If a possible OBJECT component is missing from the NDF a null column is written for that component The columns inherit the data types of 67 NDF2FITS SUN 55 31 Sp
70. data values in component DATA preserving the origi nal data type and optional UNITS and COMMENT components which specify the column s units and the meaning of the column Thus for example for the third sub file of NDF called ABC the data for column called RA would be located in ABC MORE FITS_EXT_3 COLUMNS RA DATA A random group FITS file creates an NDF for each group As they are related observations the series of NDFs are stored in a single HDS container file whose name is still given by parameter OUT Each group NDF has component name FITS_Gn where n is the group number Each group NDF contains the full header in the FITS extension appended by the set of group parameters The group parameters are evaluated using their scales and offsets and made to look like FITS cards The keywords of these FITS cards are derived from the values of PTYPEm in the main header where m is the number of the group parameter e You can supply compressed FITS files such as the Rice compression e NDF history recording is enabled in the output NDF Special Formats e NDF2FITS This is recognised by the presence of an HDUCLAS1 keyword set to NDF The conversion is similar to the general case except the processing of FITS sub files and HISTORY headers SUN 55 31 Specifications of CONVERT Applications 32 FITS2NDF An IMAGE sub file converts to an NDF VARIANCE component provided the keyword HDUCLAS2 is present and has a value that is
71. e high scaling value is less than the low value the output image will be a negative are set to 0 for positives and 255 for negatives Error messages are converted into Starlink style preceded by Usage low high ndf2gif in out scale percentiles nbins 7 sigmas Parameters IN NDF Read The name of the input NDF the sdf extension is not required OUT FILENAME Write The name of the GIF file to be generated a gif name extension is added if it is omitted If OUT is omitted the value of the IN parameter is used Any existing file with the same name will be overwritten The following parameters are actually parameters of the ADAM task NDF2TIFF Their values on the NDF2GIF command line are just passed through to NDF2TIFF which may prompt for other required values The output parameters SCAHIGH and SCALOW will be found in NDF2TIFF s parameter file HIGH _DOUBLE Read Only required if SCALE is Scale The array value that scales to 255 in the TIFF file All larger array values are set to 255 when HIGH is greater than LOW otherwise all array values less than HIGH are set to 255 The dynamic default is the maximum data value There is an efficiency gain when both LOW and HIGH are given on the command line because the extreme values need not be computed The highest data value is suggested in prompts LOW _DOUBLE Read Only required if SCALE is Scale The array value that scales to 0 in the T
72. e as follows 15 ASCII2NDF SUN 55 31 Specifications of CONVERT Applications e the ASCII file array is written to the NDF array as selected by COMP When the NDF is being modified the shape of the new component must match that of the NDF e If the input file contains a FITS like header and a new NDF is created i e COMP Data the header records are placed within the NDF s FITS extension This enables more than one array input file to be used to form an NDF Note that the data array must be created first to make a valid NDE and it s the FITS structure associated with that array that is wanted Indeed the application prevents you from doing otherwise e The FITS like header defines the properties of the NDF as follows BITPIX defines the data type 8 gives BYTE 16 produces _WORD 32 makes _INTEGER 64 creates _INT64 32 gives REAL and 64 generates DOUBLE For the first two if there is an extra header record with the keyword UNSIGNED and logical value T these types become _UBYTE and _UWORD respectively UNSIGNED is non standard since unsigned integers would not follow in a proper FITS file However here it is useful to enable unsigned types to be input into an NDF UNSIGNED may be created by this application s sister NDF2ASCII BITPIX is ignored for QUALITY data type _UBYTE is used NAXIS and NAXISn define the shape of the NDF The TITLE LABEL and BUNIT are copied to the NDF TITLE LABEL and UNITS NDF co
73. ecifications of CONVERT Applications the OBJECT structure s components Column meanings and units are assigned based upon information in the reference given below The FIELD structure components are converted into additional keywords of the same name in the binary table header with the exception that components with names longer than eight characters have abbreviated keywords UNALLOCxxx becomes UNAL xxx xxx OBJ GUI or SKY CONFIGMJD becomes CONFMJD and xSWITCHOFF becomes xSWTCHOF x X or Y If any FIELD component is missing it is ignored Keywords for the extension level name and type appear in the binary table header e JCMT SMURF Standard processing is used except for the SMURF type extension This contains NDFs such as EXP_TIME and TSYS Each such NDF is treated like the main NDF except that it is assumed that these extension NDFs have no extensions of their own FITS airlock information and HISTORY are inherited from the parent NDF Also the extension keywords are written EXTNAME gives the path to the NDF EXTLEVEL records the extension hierarchy level and EXTTYPE is set to NDF Any non NDF components of the SMURF extension are written to a binary table in the normal fashion Referesitey J A 1997 2dF Software Report 14 version 0 5 NASA Office of Standards and Technology 1994 A User s Guide for the Flexible Image Transport System FITS version 3 1 NASA Office of Standards and Technology 1995 Definition of the Flex
74. ed automatically by the application Examples ast2ndf ast_cube ndf_cube This example generates NDF data cube ndf_cube in file ndf_cube sdf from Asterix cube ast_cube in file ast_cube sdf Notes This application accepts data in the format used by the Asterix package see SUN 98 These data are cubes with two axes comprising a regular grid of positions on the sky and the third corresponding to energy or wavelength The data are Starlink HDS files which are very similar in format to a standard NDF The following points apply e The Asterix QUALITY array is non standard There is no QUALITY component in the output NDE Instead bad or null values are used to indicate missing or suspect values e The VARIANCE component is copied if it is present e The non standard Asterix axis components are replaced with standard ones e The order of the axes is rearranged Refetenc sllan and RJ Vallance 1995 in SUN 98 ASTERIX X ray Data Processing System Starlink Related Applications KAPPA AXCONV 17 DA2NDF SUN 55 31 Specifications of CONVERT Applications DA2NDEF Converts a direct access unformatted file to an NDF Description This application converts a direct access fixed length records unformatted file to anNDF It can therefore also process unformatted data files generated by C routines Only one of the array components may be created from the input file The shape of the NDF has be to be supplied
75. ed to perform the conversions In general the default parameter values are used non default parameters other than the input and output filenames are listed in the table Table 2 also contains a column headed Variable Most of the command lines issued to do the au tomatic conversion will include the translation of an environment variable named NDF_FROM_ fmt_PARS or NDF_TO_fmt_PARS as appropriate where fmt is the format name This may be used to give additional parameters to the command if you do not want to define a completely new command for yourself Where the Variable column contains a tick the variable must be used to supply the SHAPE parameter where it contains a cross additional parameters cannot be specified For example suppose application rdndf uses the NDF library to read one NDF named by the first parameter and write another named by the second parameter This application could be made to read a TEXT file data txt containing the required values for a 50 x 10 data array and write its results as a FITS file output fit as follows SUN 55 31 Automatic Format Conversion with the NDF Library 8 convert CONVERT commands are now available Version 1 4 2001 November Defaults for automatic NDF conversion are set Type conhelp for help on CONVERT commands Type showme sun55 to browse the hypertext documentation setenv NDF_FROM_TEXT_PARS SHAPE 50 10 rdndf data txt output fit The ord
76. ed to the NDF The primary headers may be written to the standard FITS airlock extension when PROFITS is TRUE The conversion from binary table columns and headers to NDF objects is as follows NPOINTS Number of elements WAVELENGTH Start wavelength axis label and units DELTAW Incremental wavelength FLUX Data array label units bad pixel flag SIGMA Data error array QUALITY Quality array remaining columns Component in IUE_MX extension NET and BACK GROUND are NDFs e IUE Final Archive MXHI This creates a series of NDFs within a single HDS container file whose name is specified by Parameter OUT Each NDF corresponds to a spectral order and may be accessed individually The name of each NDF is ORDER followed by the spectral order number For instance when OUT SWP the 85t order spectrum will be in an NDF called SWP ORDER85 Only the most significant 8 bits of the quality flags are transferred to the NDF The primary headers may be written to the standard FITS airlock extension when PROFITS is TRUE To save space this appears once in the NDF specified by Parameter OUT The conversion from binary table columns and headers to NDF objects is as follows NPOINTS Number of non zero elements WAVELENGTH Start wavelength of the non zero elements label and units STARTPIX Lower bound of the non zero elements DELTAW Incremental wavelength ABS_CAL Data array label and units QUALITY Quality array remaining Component in IUE
77. either VARIANCE or gt ERROR An IMAGE sub file converts to an NDF QUALITY component provided the keyword HDUCLAS2 is present and has value QUALITY FITS ASCII and binary tables become NDF extensions however the original structure path and data type are restored using the values of the EXTNAME and EXTTYPE keywords respectively An extension may be an array of structures the shape being stored in the EXTSHAPE keyword The shapes of multi dimensional arrays within the extensions are also restored HISTORY cards in a special format created by NDF2FITS are converted back into NDF history records This will only work provided the HISTORY headers have not been tampered Such headers are not transferred to the FITS airlock when PROFITS TRUE Any SMURF package s ancillary IMAGE sub files are restored to a SMURF extension with the original names and structure contents Thus the global HISTORY present in each sub file is not duplicated in each SMURF extension NDF e TUE Final Archive LILO LIHI SILO SIHI This converts an IUE LI or SI product stored as a FITS primary data array and IMAGE extension containing the quality into an NDF Other FITS headers are used to create AXIS structures SI products only and character components Details of the conversion are The primary data array of the FITS file becomes NDF main data array The value of Parameter FMTCNV controls whether keywords BSCALE and BZERO are applied to
78. er of the formats in the tables also defines a search path If you omit the file extension the system will search for an NDF of that name If that is absent it will try a fit FITS file If neither are present it tries an IRAF file and so on The recognised formats and their order is defined through the environment variable NDF_FORMATS_IN The shell convert startup defines NDF_FORMATS_IN as given below FITS fit FIGARO dst IRAF imh STREAM das UNFORMATTED unf UNFO dat ASCII asc TEXT txt GIF gif TIFF tif GASP hdr COMPRESSED sdf Z GZIP sdf gz FITS fits FITS fts FITS FTS Format Extension Extension Description Synonyms FITS fit fits fts FITS FIT FITS lilo lihi silo sihi mxlo mxhi rilo rihi vdlo vdhi FIGARO dst Figaro Version 2 DST IRAF imh IRAF STREAM das str Unformatted direct access or stream UNFORMATTED unf Unformatted with FITS header UNFO dat Unformatted without FITS header ASCII asc ASCII with FITS header TEXT txt ASCII without FITS header GIF gif Graphics Interchange Format TIFF tif Tag Image File Format GASP hdr GASP COMPRESSED sdf Z Compressed NDF GZIP sdf gz gzip compressed NDF Table 1 Defined Formats and Extensions 9 SUN 55 31 Acknowledgments FITS FITS FITS FIT FITS lilo FITS 1ihi FITS silo FITS sihi FITS mxlo FITS mxhi FITS rilo FITS rihi FITS vdlo FITS vdhi STREAM str but from ICL the CONVERT
79. er record is equal to the size of the first dimension of the NDF ndf2unf cluster cluster dat v This copies the variance of the NDF called cluster to an unformatted file called cluster dat The number of variance values per record is equal to the size of the first dimension of the NDF 81 Notes NDF2UNF SUN 55 31 Specifications of CONVERT Applications ndf2unf cluster cluster dat noperec 12 This copies the data array of the NDF called cluster to an unformatted file called cluster dat There are twelve data values per record in cluster dat ndf2unf out ndf234 dat fits in 234 This copies the data array of the NDF called 234 to an unformatted file called ndf234 dat The number of data values per record is equal to the size of the first dimension of the NDF If there is a FITS extension it is copied to ndf234 dat with substitution of certain keywords otherwise a minimal FITS header is produced The details of the conversion are as follows e the NDF array as selected by COMP is written to the unformatted file in records following an optional header e HISTORY is not propagated e ORIGIN information is lost e When a header is to be made it is composed of FITS like card images as follows The number of dimensions of the data array is written to the keyword NAXIS and the actual dimensions to NAXIS1 NAXIS2 etc as appropriate If the NDF contains any linear axis structures the information necessary to generate these s
80. ering 4 6 9 12 14 16 will read observations 4 6 7 8 9 12 14 15 16 Note that the brackets are required to distinguish this array of characters from a single string including commas The brackets are unnecessary when there is only one item If you wish to extract all the observations enter the wildcard 5 will read from 5 to the last observation The processing will continue until the last observation is converted The suggested value is the current value 45 IRCAM2NDF SUN 55 31 Specifications of CONVERT Applications PREFIX LITERAL Read The prefix of the output NDFs The name of an NDF is the prefix followed by the observation number The suggested value is the current value Examples ircam2ndf ircam_27aug89_1cl rhooph obs This converts the IRCAM data file called ircam_27aug89_1cl into a series of NDFs called rhooph1 rhooph2 etc There is no format conversion applied ircam2ndf ircam_27aug89_1cl rhooph 32 34 36 fmtcnv This converts four observations in the IRCAM data file called ircam_27aug89_1c1 into NDEFs called rhooph32 rhooph34 rhooph35 rhooph36 The scale and offset are applied ircam2ndf in ircam_O04nov90_1c config KTC obs 5 prefix bias This converts the fifth observation in the IRCAM data file called ircam_04nov90_1c sdf into an NDF called bias5 containing the electronic pedestal in its data array There is no format conversion applied Notes The rules for the conversion of the various components are a
81. esent they are copied verbatim to the GASP image ndf2gasp ngc253 ngc253 fillbad 1 Converts the NDF called ngc253 to a GASP image comprising the pixel file ngc253 dat and the header file ngc253 hdr Any bad values in the data array are replaced by minus one Notes The rules for the conversion are as follows e The NDF data array is copied to the dat file e The dimensions of the NDF data array is written to the hdr header file e All other NDF components are ignored 69 NDF2GASP SUN 55 31 Specifications of CONVERT Applications Related Applications CONVERT GASP2NDE References GASP documentation MUD 66 Implementation Status e The GASP image produced has by definition type SIGNED WORD There is type conversion of the data array to this type e Bad values may arise due to type conversion These too are substituted by the non null value of FILLBAD e For an NDF with an odd number of columns the last column from the GASP image is trimmed SUN 55 31 Specifications of CONVERT Applications 70 NDF2GIF NDF2GIF Converts an NDF into a GIF file Description This Bourne shell script converts an NDF into a 256 grey level Graphics Interchange Format file One or two dimensional images can be handled and various methods of scaling the data are provided The script uses the CONVERT utility NDF2TIFF to produce a TIFF file and then various NETPBM utilities to convert the TIFF file into a GIF file If th
82. esponding to two percentiles e Scale You define the upper and lower limits between which the image is to be scaled The application suggests the maximum and the minimum values minimum values when prompting e Sigmas The image is scaled between two standard deviation limits Range SIGMAS 2 _REAL Read Only required if SCALE is Sigmas The standard deviation bounds that define the scaling limits To obtain values either side of the mean both a negative and a positive value are required Thus 2 3 would scale between the mean minus two and the mean plus three standard deviations 3 2 would give the negative of that Results Parameters SCAHIGH _DOUBLE Write The array value scaled to the maximum colour index for display SCALOW _DOUBLE Write The array value scaled to the minimum colour index for display Examples ndf2tiff old new This converts the NDF called old in file 01d sdf to the TIFF file called new tif ndf2tiff horse horse pe This converts the NDF called horse in file horse sdf into a TIFF file horse tif using percentile scaling The user will be prompted for the percentiles to use Notes This application generates only 256 grey levels and does not use any image colour lookup table so absolute data values may be lost 79 NDF2TIFF SUN 55 31 Specifications of CONVERT Applications No compression is applied Related Applications CONVERT TIFF2NDF SUN 55 31 Specific
83. ew PROVENANCE parameter NDF2FITS now handles extensions containing only NDFs by adding a dummy FITS sub file that retains the name and type of the wrapper structure FITS2NDF processes SMURF package data better permitting a roundtrip via FITS perserving the original data structures save for some additional FITS headers 111 E 5 Release Notes V1 5 SUN 55 31 Release Notes E 5 11 Release Notes V1 5 14 The creation of AXIS structures by SGPECX2NDFican now be suppressed using its new AXIS parameter NDF2FITS is now much quicker when writing out WCS information that includes a large table of values E 5 12 Release Notes V1 5 15 The CADC provenance processing now also modifies the PRODUCT keyword s value in FITS extensions to the original PRODUCT string followed by underscore and the extension name in lowercase Also the CADC provenance now only records unique OBSIDD values E 5 13 Release Notes V1 5 16 The FITS converters use the new NDG provenance system that inherits history records too NDF2FITSjalso ignores hidden ancestors NDF2FITS can now handle files names with multiple fullstops in the path The formatting of history records written by FITSNDF has been improved in particular the indentation after the first line This preserves the formatting after an NDF gt FITS gt NDF cycle Various internal improvements were made particularly to reuse KAPLIBS equivalents of CONVERT subroutines Corre
84. ex to the hypertext form of this document The hypertext permits easy location of referenced documents and applications 3 Automatic Format Conversion with the NDF Library SSN 20 describes a system incorporated into the NDF library routines which enables appli cations written to read or write NDFs to handle any arbitrary foreign format for which a conversion utility can be defined The system operates via environment variables which define the set of permitted conversions and the commands required to do them 3 1 The Default Conversion Commands CONVERT startup will define defaults for the NDF conversion environment variables which permit automatic conversion of files in the formats handled by CONVERT except for AST IRCAM PGM SPECX and FITS tapes It also allows data compression The list of format names and associated filename extensions defined by CONVERT is set out in Table i the filename extensions tell the system which format the file is in For the unformatted and ASCII conversions the format names and extensions are somewhat arbitrary This list will nullify any existing list so private conversions must be added after CONVERT startup For the unformatted and ASCII conversions the format names and extensions are somewhat arbitrary The FITS and STREAM formats have synonym file extensions for the conversion to NDF The standard file extension is required for the conversion to the foreign format Table 2 lists the utilities us
85. ftp from fits cv nrao edu fits documents wcs aips27 ps Z It is currently employed by the AIPS data analysis facility amongst others so its use will facilitate data exchange with AIPS This encoding uses CROTAi and CDELTi keywords to describe axis rotation and scaling FITS AIPS This is an extension to FITS AIPS which allows the use of a wider range of celestial projections as used by the AIPS project FITS CLASS This uses the conventions of the CLASS project CLASS is a software package for reducing single dish radio and sub mm spectroscopic data It supports double sideband spectra See the GILDAS manual DSS This is the system used by the Digital Sky Survey and uses keywords AMDXn AMDYn PLTRAH etc NATIVE This is the native system used by the AST library see SUN 210 and provides a loss free method for transferring WCS information between AST based applications It allows more complicated WCS information to be stored and retrieved than any of the other encodings A comma separated list of up to six values may be supplied in which case the value actually used is the first in the list for which corresponding keywords can be found in the FITS header A FITS header may contain keywords from more than one of these encodings in which case it is possible for the encodings to be inconsistent with each other This may happen for instance if an application modifies the keyword associated with one encoding but fail
86. g CONTINUE convention http fits gsfc nasa gov registry continue_keyword htm1 EXTVER is only set when EXTNAME q v cannot accommodate the compo nent name and it is assigned the HDU index to provide a unique identifier EXTLEVEL is the level in the hierarchical structure of the extension Thus a top level extension has value 1 sub components of this extension have value 2 and so on EXTTYPE is the data type of the NDF extension used to create a binary table EXTSHAPE is the shape of the NDF extension used to create a binary table It is a comma separated list of the dimensions and is 0 when the extension is not an array HDUCLAS1 HDUCLASn NDF and the array component name respectively LBOUNDn is the pixel origin for the n dimension when any of the pixel origins is not equal to 1 This is not a standard FITS keyword XTENSION BSCALE BZERO BLANK and END are not propagated from the NDF s FITS extension XTENSION will be set for any sub file BSCALE and BZERO will be defined based on the chosen output data type in comparison with the NDF array s type but cards with values 1 0 and 0 0 respectively are written to reserve places in the header section These reservation cards are for efficiency and they can always be deleted later BLANK is set to the Starlink standard bad value corresponding to the type specified by BITPIX but only for integer types and not for the quality array
87. g point to integer or to a shorter integer type will cause the output array to be scaled and offset the values being recorded in keywords BSCALE and BZERO There is an offset keyword BZERO applied to signed byte and unsigned word types to make them unsigned byte and signed word values respectively in the FITS array this is because FITS does not support these data types The FITS keyword BLANK records the bad values for integer output types Bad values in floating point output arrays are denoted by IEEE not a number values The NDF s quality and variance arrays appear in individual FITS IMAGE sub files immediately following the primary header and data unit unless that component already appears as the primary data array The quality array will always be written as an unsigned byte array in the FITS file regardless of the value of the Parameter BITPIX e Here are details of the processing of standard items from the NDF into the FITS header listed by FITS keyword SIMPLE EXTEND PCOUNT GCOUNT all take their default values BITPIX NAXIS NAXISn are derived directly from the NDF data array how ever the BITPIX in the FITS airlock extension is transferred when Parameter BITPIX 1 CRVALn CDELTn CRPIXn CTYPEn CUNITn are derived from the NDF WCS component if possible see World Co ordinate Systems If this is not 63 NDF2FITS SUN 55 31 Specifications of CONVERT Applications possible and if PROFITS is
88. gated to the FITS files as FITS binary table sub files one per structure of the hierarchy FALSE PROFITS LOGICAL Read If TRUE the contents of the FITS extension of the NDF are merged with the header information derived from the standard NDF components See the Notes for details of the merger TRUE PROHIS LOGICAL Read If TRUE any NDF history records are written to the primary FITS header as HISTORY cards These follow the mandatory headers and any merged FITS extension headers see Parameter PROFITS TRUE PROVENANCE LITERAL Read This controls the export of NDF provenance information to the FITS file Allowed values are as follows e None No provenance is written e CADC The CADC headers are written These record the number and paths of both the direct parents of the NDF being converted and its root ancestors the ones without parents It also modifies the PRODUCT keyword to be unique for each FITS sub file e Generic Encapsulates the entire PROVENANCE structure in FITS headers in sets of five character value indexed headers there is a set for the current NDF and each parent See Section Provenance for more details None USEAXIS _LOGICAL Read Whether or not to export AXIS co ordinates to an alternate world co ordinate rep resentation in the FITS headers Such an alternate may require a FITS sub file to store lookup tables of co ordinates using the TAB projection type The default n
89. he CDELTn CRVALn CTYPEn CUNITn and CRTYPEn descriptors in the FITS extension are only copied if the input NDF contained no linear axis structures The standard order of the FITS keywords is preserved thus BITPIX NAXIS and NAXISn appear immediately after the first card image which should be SIMPLE BSCALE and BZERO in a FITS extension are copied when BITPIX is positive i e the array is not floating point An extra header record with keyword UNSIGNED and logical value T is added when the array data type is one of the HDS unsigned integer types This is done because standard FITS does not support unsigned integers and allows in conjunction with BITPIX applications reading the unformatted file to determine the data type of the array The last header record card will be the standard FITS END e Other extensions are not propagated Related Applications CONVERT UNF2NDE Implementation Status e The value of bad pixels is not written to a FITS like header record with keyword BLANK 83 SPECX2NDF SUN 55 31 Specifications of CONVERT Applications SPECX2NDF Converts a SPECX map into a simple data cube or SPECX data files to individual spectra Description This application converts a SPECX map file into a simple data cube formatted as a standard It works on map files in Version 4 2 or later of the SPECX format It can optionally write a schematic of the map grid to a text file In addition it will also conver
90. he input FITS files except for an x prefix You can also replace a specified string in the output filename for example OUT x cal Starlink replaces the string cal with Starlink in any of the output names x Some of the options create a series of NDFs in the original NDF which becomes just an HDS container and no longer an NDF PROEXTS _LOGICAL Read This governs how any extensions within the FITS file are processed in the general case If TRUE any FITS file extension is propagated to the NDF as an NDF extension called FITS_EXT_n where n is the number of the extension If FALSE any FITS file extensions are ignored The Notes of the general conversion contain details of where and in what form the various FITS file extensions are stored in the NDF This parameter is ignored when the supplied FITS file is one of the special formats including one defined by an EXTABLE but excluding NDF2FITS created files whose structure in terms of multiple FITS objects is defined Specialist NDF extensions may be created in this case See topic Special Formats for details It is also ignored if a sub file is specified as the IN parameter or Parameter CON TAINER is TRUE TRUE PROFITS LOGICAL Read If TRUE the headers of the FITS file are written to the NDF s FITS extension If a specific FITS sub file has been specified or parameter CONTAINER is TRUE or an EXTABLE is in use the FITS extension will appear as a primary header and may inc
91. he original name of the image and the date of the format conversion When PROHIS TRUE any HISTORY lines in the IRAF headers which originated from an NDF2IRAF conversion of NDF HISTORY records Such headers are not transferred to the FITS airlock when PROFITS TRUE Most axis information can be propagated either from standard FITS like keywords or certain MCWS headers Supported systems and formats are listed below FITS linear log linear Equispec linear log linear Multispec linear log linear Chebyshev and Legendre polynomials Linear and cubic Spline Explicit list of co ordinates However for Multispec axes only the first spec1 axis co ordinates are transferred to the NDF AXIS centres Any spec2 specn co ordinates present when the data array is not one dimensional or multiple fits have been stored are ignored The weights for multiple fits are thus also ignored The data type of the axis centres is REAL or _DOUBLE depending on the number of significant digits in the co ordinates or coefficients The axis labels and units are also propagated where present to the NDF AXIS struc ture In the FITS system these are derived from the CTYPEn and CUNITn keywords In the MWCS these components originate in the label and units parameters The redshift correction when present is applied to the MCWS axis co ordinates Related Applications CONVERT INDE2IRAF 43 IRAF2NDF SUN 55 31 Specificati
92. his converts the FITS files abc fit and def fts to the NDFs called fgh and ijk respectively Format conversion is applied to abc fit but not to def fts FITS extensions are created in the NDFs but there are no extensions for any FITS sub files that may be present SUN 55 31 Specifications of CONVERT Applications 30 FITS2NDF fits2ndf 256 fit 256 fmtcnv f encodings DSS This is the same as the first example except that it is specified that the co ordinate system information to be stored in the WCS component of the NDF must be based on the FITS keywords written with Digitised Sky Survey DSS images If these keywords are not present in the FITS header then no WCS component will be created All the earlier examples retained the default null value for the ENCODINGS parameter resulting in the choice of keywords being based on the contents of the FITS header see the description of the ENCODINGS parameter for details fits2ndf 256 fit 256 fmtcnv f encodings DSS native This is the same as the previous example except that if no DSS keywords are available then the co ordinate system information stored in the NDF s WCS component will be based on keywords written by applications which use the AST library see SUN 210 One such application isINDF2FITS This native encoding provides a loss free means of transferring information about co ordinate systems i e no information is lost this may not be the case with other encodings
93. hods of scaling the data are provided The routine first finds the brightest and darkest pixel values required by the particular scaling method in use It then uses these to determine suitable scaling factors and converts the image into an 8 bit representation which is then output to a simple greyscale TIFF 6 0 file If the high scaling value is less than the low value the output image will be a negative Bad values are set to 0 for positives and 255 for negatives P 8 Usage low high ndf2tiff in out scale percentiles nbins sigmas Parameters HIGH _DOUBLE Read The array value that scales to 255 in the TIFF file It is only required if SCALE is Scale All larger array values are set to 255 when HIGH is greater than LOW otherwise all array values less than HIGH are set to 255 The dynamic default is the maximum data value There is an efficiency gain when both LOW and HIGH are given on the command line because the extreme values need not be computed The highest data value is suggested in prompts IN NDF Read The name of the input NDF data structure without the sdf extension The sug gested default is the current NDF if one exists otherwise it is the current value LOW _DOUBLE Read The array value that scales to 0 in the TIFF file It is only required if SCALE is Scale All smaller array values are also set to 0 when LOW is less than HIGH otherwise all array values greater than LOW
94. ible Image Transport System FITS version 1 1 Related Applications CONVERT FITSZNDF KAPPA FITSDIN FITSIN Implementation Status e All NDF data types are supported SUN 55 31 Specifications of CONVERT Applications 68 NDF2GASP NDF2GASP Converts a two dimensional NDF into a GASP image Description This application converts a two dimensional into the GAlaxy Surface Photometry GASP package s format See the Notes for the details of the conversion Usage ndf2gasp in out fillbad Parameters IN NDF Read The input NDF data structure The suggested default is the current NDF if one exists otherwise it is the current value FILLBAD _INTEGER Read The value used to replace bad pixels in the NDF s data array before it is copied to the GASFP file The value must be in the range of signed words 32768 to 32767 A null value means no replacements are to be made This parameter is ignored if there are no bad values OUT FILENAME Write The name of the output GASP image Two files are produced with the same name but different file extensions The dat file contains the data array and hdr is the associated header file that specifies the dimensions of the image The suggested default is the current value Examples ndf2gasp abell1367 a1367 Converts an NDF called abell1367 into the GASP image comprising the pixel file a1367 dat and the header file a1367 hdr If there are any bad values pr
95. ile old sdf to the Figaro file new dst ndf2dst spectre spectre This converts the NDF called spectre in file spectre sdf to the Figaro file spectre dst Notes The rules for the conversion are as follows NDF Figaro file Comments Main data array Z DATA Imaginary array Z IMAGINARY Bad pixel flag gt ZFLAGGED Units gt Z UNITS Label Z LABEL Variance gt Z ERRORS After processing Quality gt It is not copied directly though indicated by QUALITY flags will be flagged in Z DATA in addition to any flagged val ues actually in the input main data array Z FLAGGED is set accordingly SUN 55 31 Specifications of CONVERT Applications 56 NDF2DST NDF Figaro file Comments Title gt OBS OBJECT AXIS 1 structure gt X AXIS 1 Data gt X DATA_ARRAY unless there is a DATA component of AXIS 1 MORE FIGARO to allow for a non 1 dimensional array AXIS 1 Variance gt X VARIANCE unless there is a VARIANCE component of AXIS 1 MORE FIGARO to allow for a non 1 dimensional array AXIS 1 Width gt X WIDTH unless there is a WIDTH component of AXIS 1 MORE FIGARO to allow for a non 1 dimensional array AXIS 1 Units gt X UNITS AXIS 1 Label gt X LABEL AXIS 1 MORE FIGARO xxx X xxx Similarly for AXIS 2 AXIS 6 which are renamed to Y T U V or W FIGARO extension MORE FIGARO MAGFLAG Z MAGFLAG MORE FIGARO RANGE gt
96. inate systems However some legacy applications such as Figaro do not recognise WCS and for these Axis is more appropriate If you are mixing data processing packages then you may need Both but care should be exercised to avoid inconsistent representations especially if the data are exported to FITS with NDF2FITS see its Parameter USEAXIS wcs Examples fits2ndf 256 fit 256 fmtcnv f This converts the FITS file called 256 fit to the NDF called f256 The data type of the NDF s data array matches that of the FITS primary data array A FITS extension is created in f256 and FITS sub files are propagated to NDF extensions fits2ndf 256 fit 256 fmtcnv native type _real As above but now a _REAL type scaled data array is created assuming that 256 fit contains scaled integer data with BITPIX 8 or 16 and non default BSCALE and BZERO keywords fits2ndf 256 fit 256 fmtcnv t type _real wcscomp axis 29 FITS2NDF SUN 55 31 Specifications of CONVERT Applications As the first example but now a _REAL type data array is created by applying the scale and offset from BSCALE and BZERO keywords to the integer values stored in 256 fit Co ordinate information is written only to the AXIS structure fits2ndf 256 fit 256 noprofits noproexts As the previous example except there will be a format conversion from a FITS integer data type to floating point in the NDF using the BSCALE and BZERO keywords and there will be no extensio
97. iner file of the supplied NDF is used to store a series of NDFs one for each observation called OBSn where n is the observation number Each observation comprises three rows in the binary table corresponding to the flux the rm s errors and the integration times The conversion from binary table columns to NDF objects is as follows 35 FITS2NDF SUN 55 31 Specifications of CONVERT Applications ARRAY Data error exposure arrays depending on the value of column TYPE BLANK Data blank i e undefined value BUNIT Data units BSCALE Data scale factor BZERO Data offset CDELTn Pixel increment along axis n CRPIXn Axis n reference pixel CRVALn Axis n co ordinate of reference pixel CTYPEn Label for axis n CUNITn Units for axis n NAXIS Number of dimensions NAXISn Dimension of axis n remaining columns Keyword in FITS extension Some of these remaining columns overwrite the global values in the primary headers The integration times are stored as an NDF within an extension called EXPOSURE The creation of axis information and extensions does not occur for the error array as these are already generated when the data array row in the binary table is processed The BITPIX column is ignored as the data type is determined through the use the TFORMn keyword and the value of FATCNV in conjunction with the BSCALE and BZERO columns e ISO LWS auto analysis LWS AN The conversion from binary table columns to NDF objects i
98. ions not a number value also become bad values in the NDF s data array The BAD_PIXEL flag is set appropriately e NDF quality and variance arrays are not created e A verbatim copy of the FITS primary header is placed in the NDF s FITS extension when Parameter PROFITS is TRUE e Here are details of the processing of standard items from the the FITS header listed by FITS keyword CRVALn CDELTn CRPIXn CTYPEn CUNITn define the NDF s WCS and or AXIS components see Parameters ENCODINGS and WCSCOMP OBJECT LABEL BUNIT if present are equated to the NDF s TITLE LABEL and UNITS components respectively LBOUNDn if present this specifies the pixel origin for the n dimension e Additional sub files within the FITS files are converted into extensions within the NDF if Parameter PROEXTS is TRUE These extensions are named FITS_EXT_m for the m sub file e AnIMAGE sub file is treated like the primary data array and follows the rules give above However the resultant NDF is an extension of the main NDE e A BINTABLE or TABLE sub file is converted into a structure of type TABLE This has a NROWS component specifying the number of rows and a COLUMNS struc ture containing a series of further structures each of which takes its name from the label of the corresponding column in the FITS table If there is no label for the nth column the structure is called COLUMNn These COLUMN structures contain a column of table
99. irect parents for the nth ancestor PRVDn is the creation date in ISO order of the nth ancestor PRVCn is the software used to create the nth ancestor SUN 55 31 Specifications of CONVERT Applications 66 NDF2FITS e PRVMn lists the contents of the MORE structure of the nth parent All have value lt unknown gt if the information could not be found except for the PRVMn header which is omitted if there is no MORE information to record The index n used in each keyword s name is the provenance identifier for the NDF and starts at 0 for the NDF being converted to FITS The following PROVENANCE headers are written if parameter PROVENANCE is set to CADC e PRVCNT is the number of immediate parents e PRVm is name of the mth immediate parent e OBSCNT is the number of root ancestor OBSm headers e OBSm is mth root ancestor identifier from its MORE OBSIDSS component FILEID is the name of the output FITS file omitting any file extension e PRODUCT is modified or added to each sub file s header to be the primary header s value of PRODUCT with a _ lt extnam gt suffix where lt extnam gt is the extension name in lowercase When PROFITS is TRUE any existing provenance keywords in the FITS airlock are not copied to the FITS file Quality Masking NDF automatic quality masking is a facility whereby any bad quality information flagged by the bad bits mask present can be incorporated in the
100. irst dimension varies fastest followed by the second dimension and so on For example a 2x2x2 element cube s indices will appear in the order 1 1 1 2 1 1 1 2 1 2 2 1 1 1 2 2 1 2 1 2 2 2 2 2 e HISTORY is not propagated e ORIGIN information is lost When a header is to be made it is composed of FITS like card images as follows The number of dimensions of the data array is written to the keyword NAXIS and the actual dimensions to NAXIS1 NAXIS2 etc as appropriate SUN 55 31 Specifications of CONVERT Applications 52 NDF2ASCII If the NDF contains any linear axis structures the information necessary to generate these structures is written to the FITS like headers For example if a linear AXIS 1 structure exists in the input NDF the value of the first data point is stored with the keyword CRVAL1 and the incremental value between successive axis data is stored in keyword CDELT1 By definition the reference pixel is 1 0 and is stored in keyword CRPIX1 If there is an axis label it is written to keyword CTYPE1 and axis unit is written to CUNIT1 Similarly for AXIS 2 structures etc FITS does not have a standard method of storing axis widths and variances so these NDF components will not be propagated to the header Non linear axis data arrays cannot be represented by CRVALn and CDELTn and must be ignored If the input NDF contains TITLE LABEL or UNITS components these are stored with the keywords TITL
101. is copies the variance of the NDF called cluster to a direct access unformatted file called cluster dat The number of variance values per record is equal to the size of the first dimension of the NDF ndf2da cluster cluster dat noperec 12 This copies the data array of the NDF called cluster to a direct access unformat ted file called cluster dat There are twelve data values per record in cluster dat Notes The details of the conversion are as follows SUN 55 31 Specifications of CONVERT Applications 54 NDF2DA e the NDF array as selected by COMP is written to the unformatted file in records e all other NDF components are lost Related Applications CONVERT DA2NDF 55 NDF2DST SUN 55 31 Specifications of CONVERT Applications NDF2DST Converts an NDF to a Figaro Version 2 DST file Description This application converts an to a FIGARO Version 2 DST file The rules for convert ing the various components of a DST are listed in the Notes Since both are hierarchical formats most files can be be converted with little or no information lost Usage ndf2dst in out Parameters IN NDF Read Input NDF data structure The suggested default is the current NDF if one exists otherwise it is the current value OUT Figaro Write Output Figaro file name This excludes the file extension The file created will be given extension dst Examples ndf2dst old new This converts the NDF called old in f
102. ited to a maximum of 1024 by 1024 elements It must be two dimensional e The GASP image is written to the NDF s data array The data array has type WORD No other NDF components are created e If the header file is corrupted you must remove the offending hdr file or specify the shape of the GASP image on the command line otherwise the application will continually abort Related Applications CONVERT NDF2GASP 39 GASP2NDF SUN 55 31 Specifications of CONVERT Applications References GASP documentation MUD 66 SUN 55 31 Specifications of CONVERT Applications 40 GIF2NDF GIF2NDF Converts a GIF file into an NDF Description This Bourne shell script converts a Graphics Interchange Format GIF file into an unsigned byte 256 grey level format file It handles one or two dimensional images The script uses various utilities to produce a FITS file flipped top to bottom and then FITSZNDF to produce the final NDF Error messages are converted into Starlink style preceded by Usage gif2ndf in out Parameters IN FILENAME Read The name of the GIF file to be converted A gif name extension is assumed if omitted OUT NDF Write The name of the NDF to be generated without the sdf extension If the OUT parameter is omitted the value of the IN parameter is used Examples gif2ndf old new This converts the GIF file old gif into an NDF called new in file new sdf gif2ndf horse Thi
103. ity preserves the data compression of large files In the absence of a scaled array the application behaves as if BITPIX 1 were specified E 5 6 Release Notes V1 5 9 NDEZ2FITS Parameter ENCODING has a new allowed value of FITS WCS CD This is the same as FITS WCS except that it uses the old CD matrix formalism to describe the data array s rotation and scaling E 5 7 Release Notes V1 5 10 FITS2NDFisupports externally and internally compressed FITS files NDEF2FITS writes integrity check keywords CHECKSUM and DATASUM at the end of each header if new Parameter CHECKSUMS is TRUE E 5 8 Release Notes V1 5 11 NDF2FITS writes the correct BUNIT keyword value in the IMAGE extension storing the VARI ANCE component The BUNIT keyword is absent for a QUALITY array There is anew DUPLEX parameter When set TRUE and PROFITS is also TRUE it permits the FITS airlock headers to appear also in the IMAGE extensions for the VARIANCE and QUALITY arrays E 5 9 Release Notes V1 5 12 NDF2FITS now makes special provision for the JCMT SMURF package extension It treats the extension contents as NDFs rather than arbitrary HDS structures E 5 10 Release Notes V1 5 13 NDF2FITS supports the propagation of provenance information to FITS headers There is a choice of generic propagation that attempts to propagate all the information or to write CADC specific headers or to exclude provenance the default governed by the n
104. ively if you wish to explicitly enter the latitude and longitude enter COORDS The values are not case sensitive JCMT Examples specx2ndf specx_map specx_cube This example generates an NDF data cube called specx_cube in file specx_cube sdf from the NDF SPECX map called specx_map in file specx_map sdf A text file containing a schematic of the map grid will not be produced specx2ndf specx_map specx_cube gridfile map grid This example generates an NDF data cube called specx_cube in file specx_cube sdf from the NDF SPECX map called specx_map in file specx_map sdf A text file containing a schematic of the map grid will be written to file map grid Input and output map formats SPECX map files are written by the SPECX package see SUN 17 for reducing spectra observed with heterodyne receivers operating in the mm and sub mm wavelength range of the electromagnetic spectrum SPECX is usually used to process observations obtained with the James Clerk Maxwell Telescope JCMT in Hawaii A SPECX map file comprises a regular rectangular two dimensional grid of map positions on the sky with spectra observed at the grid points However a spectrum is not necessarily available at every grid position at some positions a spectrum is not observed in order to save observing time For example for a grid centred on a typical roughly circular 85 SPECX2NDF SUN 55 31 Specifications of CONVERT Applications object spe
105. l values SUN 55 31 Specifications of CONVERT Applications 58 NDF2FITS e BITPIX 0 will cause the output file to have the data type equivalent to that of the input NDF e BITPIX 1 requests that the output file has the data type corresponding to the value of the BITPIX keyword in the NDF s FITS extension If the extension or BITPIX keyword is absent the output file takes the data type of the input array e BITPIX Native requests that any scaled arrays in the NDF be copied to the scaled data type Otherwise behaviour reverts to BITPIX 1 which may in turn be effectively BITPIX 0 The case insensitive value may be abbreviated to n BITPIX values must be enclosed in double quotes and may be a list of comma separated values to be applied to each conversion in turn An error results if more values than the number of input NDFs are supplied If too few are given the last value in the list is applied to the remainder of the NDFs thus a single value is applied to all the conversions The given values must be in the same order as that of the input NDEFs Indirection through a text file may be used If more than one line is required to enter the information at a prompt then type a at the end of each line where a continuation line is desired 0 CHECKSUM _LOGICAL Read If TRUE each header and data unit in the FITS file will contain the integrity check keywords CHECKSUM and DATASUM immediately before the END card TRUE COMP LITE
106. les using the new double sideband SpecFrame See the AST documentation for more details on double sideband spectra E 5 3 Release Notes V1 5 6 FITSGZ is a new on the fly conversion format for GZIP compressed FITS files The recognised extensions are fits gz fit gz and fts gz FITS2NDF supports the new AAO Instruments AAOMEGA and FMOS that use the 2dF data structures E 5 4 Release Notes V1 5 7 FITS2NDFihas a new TYPE group parameter to set the data type of the NDF overriding the value propagated from the FITS BITPIX or BSCALE and BZERO precision when FMTCNV is TRUE NDF2FITS now supports multi NDFs HDS container files through the new CONTAINER and MERGE parameters SUN 55 31 Release Notes 110 E 5 Release Notes V1 5 E 5 5 Release Notes V1 5 8 FITS2NDF Parameter FMTCNV has a new allowed value of Native requesting that there is no format conversion and the array of numbers stored in the FITS file are copied to a scaled array within the NDF This preserves the data compression Parameter TYPE continues to control the data type of the true unscaled values NDF2FITS Parameter BITPIX has a new allowed value of Native This requests that should any scaled form arrays be converted then the data type of the corresponding output FITS array is set to the scaled form array s data type and that the scale and offset coefficients for the format conversion are taken from the NDF s scaled array too This new facil
107. like IRAF In addition it assists packages that wish to move to using the NDF CONVERT is available from all three UNIX platforms supported by Starlink The supported conversions are currently as follows 1 See SUN 33 for an introduction to the NDE SUN 55 31 Introduction 2 Converts a text file to an NDF gt io Q S i z rrj Converts an Asterix data cube into a standard NDF gt re N E J er Converts a direct access unformatted file to an NDF f gt R Z J er Converts a Figaro Version 2 DST file to an NDF Converts FITS files into NDFs a g Nn ills S 5 Converts an image in GASP format to an NDF GIF2NDF Converts an image in GIF format to an NDF IRAF2NDF Converts an IRAF image to an NDF IRCAM2NDF Converts an IRCAM data file to a series of NDFs Converts a FITS tape to one or more NDFs Converts an NDF to a text file f J Prj N gt e2 e Converts an NDF to a direct access unformatted file f J Prj N g gt Converts an NDF to a Figaro Version 2 DST file Converts an NDF to a FITS file Z z J g rrj rri N N ay 9 TE Converts a two dimensional NDF into a GASP image Converts an NDF to a GIF file f J Prj N Q Converts an NDF to an IRAF image Converts an NDF to a PGM format z Z Oo J eri Ppi RI S aw z z Converts an NDF
108. lso attempts to use the FIT WCS encoding before any other Added support for the SMURF_EXT type for the SMURF extension and for extensions within the SMURF extension s NDFs SPECX2NDF converts the GSD bad value into the Starlink equivalent The IDL scripts READ_NDFjand WRITE_NDFihave been fixed to use STARLINK_DIR to specify the correct IDL library path E 5 17 Release Notes V1 6 Support for FITS TAB projection type added Add WCSCOMP parameter to FITSZ2NDF It controls where world co ordinate information is propagated in the output NDF Add USEAXIS parameter to NDF2FITS It controls whether AXIS co ordinate information can be stored in an alternate representation in the FITS headers that may include a TAB extension The default behaviour is to not write alternate AXIS co ordinates if a WCS component exists in the NDF Changed the default ORIGIN keyword from Starlink Project U K toStarlink Software in NDF2FITS E 5 18 Release Notes V1 7 Support for 64 bit integers is now available in ASCIIZ2NDF DA2NDF FITS2NDF NDF2ASCII NDF2DA NDF2FITS NDF2UNF and UNF2NDF NDF2FITS now avoids scaling when the range of data values lies within the scaled type s range such as double to single precision NDF2FITS has a new boolean parameter called ALLOWTAB to permit or disable storage of tabular co ordinates using the FITS WCS TAB algorithm SPECX2NDFihas a new SYSTEM parameter that specifies the NDF s co ordinate system
109. lude cards inherited from the primary HDU otherwise the FITS header is written verbatim TRUE TYPE LITERAL Read The data type of the output NDF s data and variance arrays It is normally one of the following HDS types _BYTE _WORD _REAL _INTEGER _INT64 _DOUBLE _UBYTE _UWORD corresponding to signed byte signed word real integer 64 bit integer double precision unsigned byte and unsigned word See SUN 92 for further details An unambiguous abbreviation may be given TYPE is ignored when COMP Quality since the QUALITY component must comprise unsigned bytes equivalent to TYPE _UBYTE to be a valid NDF The suggested default is the current value Note that setting TYPE may result in a loss of precision and should be used with care A null value or blank requests that the type be propagated from the FITS using SUN 55 31 Specifications of CONVERT Applications 28 FITS2NDF the BITPIX keyword or if FMTCNV is TRUE the type is either REAL or DOUBLE depending on the precision of the BSCALE and BZERO keywords TYPE may be a list of comma separated values enclosed in double quotes that are applied to each conversion in turn An error results if more values than the number of input FITS files are supplied If too few are given the last value in the list is applied to all the conversions thus a single value is applied to all the input files If more than one line is required to enter the information a
110. ment variable oifversion 1 CONVERT contains IRAF V2 11 compatible versions of the SPP routines and the IRAF libraries If you are still running IRAF V2 10 set environment variable oifversion 1 before running NDF2IRAF This includes when running Starlink programs from IRAF cl if an output image is produced by on the fly conversion Details of which IRAF version libraries are used in CONVERT will be given in the release notes E Release Notes E 1 Release Notes V1 2 E 1 1 New Applications READ_NDF An IDL function to read an NDF component into an IDL array WRITE NDF An IDL procedure to write an IDL array to an NDF component The use of these converters for IDL is described in Section B E 1 2 Changed applications NDF2TIFF Various alternative methods of scaling the NDF data are provided NDF2GIF Various alternative methods of scaling the NDF data are provided the scaling is performed by NDF2TIFF NDE2FITS Now has an additional parameter ENCODING to control the way WCS informa tion is encoded within the FITS header NDF2IRAF and IRAF2NDF These are re built using libraries from IRAF release V2 11 1 107 E 2 Release Notes V1 2 4 SUN 55 31 Release Notes E 1 3 Documentation This document and CONVERT help has been modified to reflect these changes E 2 Release Notes V1 2 4 All the converters which are ADAM tasks have been combined into a monolith to save disk space The FITS converters now u
111. mponents by means of entries in a file see the EXTABLE parameter Details of the supported special formats and rules for processing them are given in topic Special Formats the general case processing rules are described in the Notes FITS2NDEF can also process both external and internal compressed FITS files The external compression applies to the whole file and FITS2NDF recognises gzip gz and UNIX compress Z formats Internal compressions are where a large image is tiled and each tile is compressed The supported formats are Rice the IRAF PLIO and GZIP Both NDF and FITS use the term extension and they mean different things Thus to avoid confusion in the descriptions below the term sub file is used to refer to a FITS IMAGE TABLE or BINTABLE Header and Data Unit HDU Usage fits2ndf in out Parameters CONTAINER _LOGICAL Read If TRUE causes each HDU from the FITS file to be written as a component of the HDS container file specified by the OUT parameter Each component will be named HDU_n where n is the FITS HDU number The primary HDU is numbered 0 Primary and IMAGE HDUs will become NDFs and if the PROFITS parameter is TRUE each NDF s FITS extension will be created from the header of the FITS sub file It will have the form of a primary header and may include cards inherited from the primary header If the FITS HDU has no data array an NDF will not be created if PROFITS is TRUE a structure of type FI
112. mponents respectively The CDELTn CRVALn CTYPEn and CUNITn keywords make linear axis struc tures within the NDF CUNITn define the axis units and the axis labels are assigned to CTYPEn If some are missing pixel co ordinates are used for those axes BSCALE and BZERO in a FITS extension are ignored BLANK is not used to indicate which input array values should be assigned to a END indicates the last header record unless it terminates a dummy header and the actual data is in an extension e Other data item such as HISTORY data ORIGIN and axis widths are not supported because the text file has a simple structure to enable a diverse set of input files to be converted to NDFs and to limitations of the standard FITS header Related Applications CONVERT NDF2ASCII KAPPA TRANDAT FIGARO ASCIN and ASCOUT SUN 55 31 Specifications of CONVERT Applications 16 AST2NDF AST2NDF Converts an Asterix data cube into a simple NDF Description This application converts an Asterix data cube into a standard See Section Notes below for details of the conversion Usage ast2ndf in out Parameters IN NDF Read The name of the input Asterix data cube The file extension sdf should not be included since it is appended automatically by the application OUT NDF Write The name of the output NDF containing the data cube written by the application The file extension sdf should not be included since it is append
113. nes the properties of the NDF as follows BITPIX defines the data type 8 gives BYTE 16 produces _WORD 32 makes _INTEGER 64 creates _INT64 32 gives REAL and 64 generates DOUBLE For the first two if there is an extra header record with the keyword UNSIGNED and logical value T these types become _UBYTE and UWORD respectively UNSIGNED is non standard since unsigned integers would not follow in a proper FITS file However here it is useful to enable unsigned types to be input into an NDF UNSIGNED may be created by this application s sister NDF2UNF BITPIX is ignored for QUALITY data type _UBYTE is used NAXIS and NAXISn define the shape of the NDF The TITLE LABEL and BUNIT are copied to the NDF TITLE LABEL and UNITS NDF components respectively The CDELTn CRVALn CTYPEn and CUNITn keywords make linear axis struc tures within the NDF CUNITn define the axis units and the axis labels are assigned to CTYPEn If some are missing pixel co ordinates are used for those axes BSCALE and BZERO in a FITS extension are ignored BLANK is not used to indicate which input array values should be assigned to a END indicates the last header record unless it terminates a dummy header and the actual data is in an extension e Other data item such as HISTORY data ORIGIN and axis widths are not supported because the unformatted file has a simple structure to enable a diverse set of input files to be converted to ND
114. noperec 8 This copies a data array from the unformatted file ngc253 dat to the NDF called ngc253 The input file does not contain a header section The NDF is two dimensional 100 elements in x by 60 in y Its data array has type _REAL The data records each have 8 values unf2ndf ngc253q dat ngc253 q 100 shape 100 60 This copies a quality array from the unformatted file ngc253q dat to an existing NDF called ngc253 such as created in the first example The input file does not contain a header section The NDF is two dimensional 100 elements in x by 60 in y Its data array has type _UBYTE The data records each have 100 values unf2ndf ngc253 dat ngc253 fits noperec This copies a data array from the unformatted file ngc253 dat to the NDF called ngc253 The input file contains a FITS like header section which is copied to the FITS extension of the NDF The shape of the NDF is controlled by the mandatory FITS keywords NAXIS AXIS1 AXISn and the data type by keywords BITPIX and UNSIGNED Each data record has AXIS1 values except perhaps for the last unf2ndf type _uword in ngc253 dat out ngc253 This copies a data array from the unformatted file ngc253 dat to the NDF called ngc253 The input file does not contain a header section The NDF has the current shape and data type is unsigned word The current number of values per record is used unf2ndf spectrum zz skip 2 shape 200 noperec This copies a data array from the unfo
115. noprofits bitpix 32 This converts the NDFs with names beginning with a and ending in z in the directory called data into FITS files of the same name and with a file extension of f it The variance array becomes the data array of each new FITS file The data type of the FITS primary data array single precision floating point Any FITS extension in the NDF is ignored ndf2fits abc def jvp1 fit jvp2 fit comp d bitpix 16 64 This converts the NDFs called abc and def into FITS files called jvp1 fit and jvp2 fit respectively The data type of the FITS primary data array is signed integer words in jvp1 fit and double precision floating point in jvp2 fit The FITS extension in each NDF is merged into the FITS header of the corresponding FITS file ndf2fits horse logo fit d native encoding fits wcs This is the same as the first example except that the co ordinate system informa tion stored in the NDF s WCS component is written to the FITS file twice once using the FITS WCS headers and once using a special set of native keywords recognised by the AST library see SUN 210 The native encoding provides a loss free means of transferring co ordinate system information i e no information is lost other encodings may cause information to be lost Only applications based on the AST library such as FITS2NDF are able to interpret native encodings ndf2fits u20040730_00675 merge container accept This converts the UIST
116. ns written within f256 fits2ndf fit p fits This converts a set of FITS files given by the list fit p fits where is the match any character wildcard The resultant NDFs take the filenames of the FITS files so if one of the FITS files was parker fits the resultant NDF would be called parker Format conversion is performed on integer data types A FITS extension is created in each NDF and any FITS sub files present are propagated to NDF extensions fits2ndf swp25000 mxlo mx1025000 This converts the IUE MXLO FITS file called swp25000 mxlo to the NDF called mx1025000 Should the dataset comprise both the large and small aperture spectra they will be found in NDFs mx1025000 Large and mx1025000 small respectively fits2ndf SWP19966 MXHI mxhi19966 This converts the IUE MXHI FITS file called SWP19966 MXHI to a series of NDFs within a file mxhi19966 sdf Each NDF corresponds to an order Thus for instance the one hundredth order will be in the NDF called mxhi19966 order100 fits2ndf data silo silox swp noprofits This converts all the IUE SILO FITS files with file extension silo in directory data to NDFs in the current directory Each name of an NDF is derived from the corresponding FITS filename the original name has the swp removed and silo is prefixed So for example swp25000 silo would become an NDF called silo25000 No FITS extension is created fits2ndf abc fit def fts fgh ijk fmtcnv F T noproexts T
117. nt name The column order is the same as the component order The shapes of multi dimensional arrays are recorded using the TDIMn keyword where n is the column number The HEASARCH convention for specifying the width of character arrays keyword TFORMn rAw where r is the total number of characters in the column and w is the width of an element is used The EXTNAME EXTTYPE EXTSHAPE and EXTLEVEL keywords see above are written to the binary table header There are additional rules if a multi NDF container file is being converted see Parameter CONTAINER This excludes the case where there are but two NDFs one data and the other just headers that have already been merged see Parameter MERGE e For multiple NDFs a header only HDU may be created followed by an IMAGE sub file containing the data array or whichever other array is first specified by COMP e BITPIX for the header HDU is set to an arbitrary 8 e Additional keywords are written for each IMAGE sub file HDSNAME is the NDF name for a component NDF in a multi NDF container file for example 12 HDSTYPE is set to NDF for a component NDF in a multi NDF container file World Co ordinate Systems Any co ordinate system information stored in the WCS component of the NDF is written to the FITS header using one of the following encoding systems the encodings used are determined by parameters ENCODING and NATIVE e FITS IRAF This uses keywords CRVALi CRP
118. on floating point integer or byte values though somewhat inefficiently in terms of memory consumption B 2 2 A faster route but a little more complicated However the NDF2ASCII routine is not fast and makes this route awkward if time is important Consequently you may want to use NDF2UNFito create an F77 unformatted sequential file thus ndf2unf in imagein out fileout noperec 339 Where the noperec number should be the size of the first axis of the image You can then read the created file using an IDL batch file similar to Supply the name of the image and its dimensions FNAME fileout SD1 339 SD2 244 Set up the main array and temporary array use NOZERO option to avoid initialisation IMAGE INTARR SD1 SD2 NOZERO TEMP INTARR SD1 NOZERO Display what is going on PRINT Converting file FNAME Open the file generated by NDF2UNF for read access only OPENR UNIT fname GET_LUN F77_UNFORMATTED Read the image one record at a time FOR I 0 SD2 1 DO BEGIN READU UNIT TEMP amp Transfer each line into the main image array FOR J 0 SD1 1 DO BEGIN IMAGE J I TEMP J amp ENDFOR amp ENDFOR Close the opened file unit CLOSE 1 Scale the image for display IMAGE CONGRID IMAGE SD1 SD2 INTERP WINDOW 0 XSIZE SD1 YSIZE SD2 Display the image TVSCL IMAGE The image is then contained in the integer array IMAGE and may be manipulated by IDL This would allow such opera
119. on prevents you from doing otherwise e Other data items such as axes are not supported because of the direct access file s simple structure Related Applications CONVERT INDE2DA 19 DST2NDF SUN 55 31 Specifications of CONVERT Applications DST2NDF Converts a Figaro Version 2 DST file to an NDF Description This application converts a FIGARO Version 2 DST file to a Version 3 file i e to an The rules for converting the various components of a DST are listed in the Notes Since both are hierarchical formats most files can be be converted with little or no information lost Usage dst2ndf in out Parameters FORM LITERAL Read The storage form of the NDF s data and variance arrays FORM Simple gives the simple form where the array of data and variance values is located in an ARRAY structure Here it can have ancillary data like the origin This is the normal form for an NDF FORM Primitive offers compatibility with earlier formats such as IMAGE In the primitive form the data and variance arrays are primitive components at the top level of the NDF structure and hence it cannot have ancillary information Simple IN Figaro file Read The file name of the version 2 file A file extension must not be given after the name since dst is appended by the application The file name is limited to 80 characters OUT NDF Write The file name of the output NDF file A file extension must not be given after
120. ons of CONVERT Applications Pitfalls e Bad pixels in the IRAF image are not replaced e Some of the routines required for accessing the IRAF header file are written in SPP Macros are used to find the start of the header line section this constitutes an Interface violation as these macros are not part of the IMFORT interface specification It is possible that these may be changed in the future so beware References IRAF User Handbook Volume 1A A User s Guide to FORTRAN Programming in IRAF the IMFORT Interface by Doug Tody Keywords CONVERT IRAF Implementation Status e Only handles one two and three dimensional IRAF files e The NDF produced has type WORD or _REAL corresponding to the type of the IRAF image The IRAF IMFORT FORTRAN subroutine library only supports these data types signed words and real The pixel type of the image can be changed from within IRAF using the chpixtype task in the images package e See Release Notes for IRAF Version compatibility SUN 55 31 Specifications of CONVERT Applications 44 IRCAM2NDF IRCAM2NDF Converts an IRCAM data file to a series of NDFs Description This applications converts an HDS file in the IRCAM format listed in IRCAM User Note 11 to one or more NDF53 See the for a detailed list of the rules of the conversion Usage ircam2ndf in prefix obs config Parameters CONFIG LITERAL Read The choice of data array to place in the N
121. pass an EXTABLE parameter to the FITS2NDF operation to select extensions e Only tape devices for which the mt and dd commands will work may be used Related Applications KAPPA FITSDIN FITSIN CONVERT FITSZ2NDF SUN 55 31 Specifications of CONVERT Applications 50 NDF2ASCII NDF2ASCII Converts an NDF to a text file Description This application converts an NDF to a Fortran text file Only one of the array components may be copied to the output file Preceding the data there is an optional header consisting of either the FITS extension with the values of certain keywords replaced by information derived from the NDF or a minimal FITS header also derived from the NDF The output file uses LIST carriagecontrol Usage ndf2ascii in out comp reclen noperec Parameters COMP LITERAL Read The NDF component to be copied It may be Data Quality or Variance Data FITS LOGICAL Read If TRUE any FITS extension is written to start of the output file unless there is no extension whereupon a minimal FITS header is written to the ASCII file FALSE FIXED LOGICAL Read When FIXED is TRUE the output file allocates a fixed number of characters per data value The number of characters chosen is the minimum that prevents any loss of precision and hence is dependent on the data type of the NDF array These widths in characters for each HDS data type are as follows _UBYTE 3 BYTE 4 UWORD 5 _WORD 6 INT
122. per record of the input file It must be positive on UNIX systems The suggested default is the size of the first dimension of the array if there is no current value A null value for NOPEREC causes the size of first dimension to be used OUT NDF Read and Write Output NDF data structure When COMP is not Data the NDF is modified rather than a new NDF created It becomes the new current NDF SHAPE _INTEGER Read The shape of the NDF to be created For example 40 30 20 would create 40 columns by 30 lines by 10 bands It is only accessed when FITS is FALSE SKIP INTEGER Read The number of header records to be skipped at the start of the input file before finding the data array or FITS like header 0 TYPE LITERAL Read The data type of the input file and output NDF It must be one of the following HDS types _BYTE _WORD _REAL _INTEGER _INT64 _DOUBLE _UBYTE SUN 55 31 Specifications of CONVERT Applications 90 UNF2NDF _UWORD corresponding to signed byte signed word real integer double precision unsigned byte and unsigned word See SUN 92 for further details An unambigu ous abbreviation may be given TYPE is ignored when COMP Quality since the QUALITY component must comprise unsigned bytes equivalent to TYPE UBYTE to be a valid NDF The suggested default is the current value TYPE is also only accessed when FITS is FALSE _REAL Examples unf2ndf ngc253 dat ngc253 shape 100 60
123. ppmtopgm pnmflip and pnmtofits must be available on your PATH Related Applications CONVERT INDE2 TIFF 89 UNF2NDF SUN 55 31 Specifications of CONVERT Applications UNF2NDF Converts a sequential unformatted file to an NDF Description This application converts a sequential unformatted Fortran file to an NDF Only one of the array components may be created from the input file Preceding the input data there may be an optional header This header may be skipped or may consist of a simple FITS header In the former case the shape of the NDF has be to be supplied Usage unf2ndf in out comp noperec skip shape type Parameters COMP LITERAL Read The NDF component to be copied It may be Data Quality or Variance To create a variance or quality array the NDF must already exist Data FITS LOGICAL Read If TRUE the initial records of the unformatted file are interpreted as a FITS header with one card image per record from which the shape data type and axis centres are derived The last record of the FITS like header must be terminated by an END keyword subsequent records in the input file are treated as an array component given by COMP FALSE IN FILENAME Read Name of the input sequential unformatted Fortran file The file will normally have variable length records when there is a header but always fixed length records when there is no header NOPEREC _INTEGER Read The number of data values
124. pression specifying the NDF component to be written The following values are allowed DATA A new NDF is created with the same dimensions as the IDL array and the DATA component written VARIANCE An existing NDF is opened and a new component written The size of the given array must be the same as the NDF SUN 55 31 Specifications of CONVERT IDL Procedures 100 WRITE_NDF QUALITY An existing NDF is opened and a new component written The size of the given array must be the same as the NDF and the type of the IDL array must be Byte The case of the string does not matter and it may be abbreviated to one or more characters 101 WRITE_NDF SUN 55 31 Specifications of CONVERT IDL Procedures Examples Assuming my_data is an IDL floating array IDL gt write_ndf my_data my_ndf creates the NDF my_ndf sdf with the same dimensions as the IDL array my_data and writes the array to its DATA component of type _REAL No checks on bad values are made IDL gt write_ndf my_data my_ndf values f_nan As above except that any occurrence of the value NaN in the array will be replaced by the VAL_ BADR value as defined by the Starlink PRIMDAT package IDL gt write_ndf my_variances my_ndf comp v Writes the IDL array my_variances to the VARIANCES component of the NDF created above A check is made that the size of the array corresponds with the size of the NDF Note that the key
125. rary name and the other called HEADER that stores the global headers of the dataset TRUE ORIGIN LITERAL Read The origin of the FITS files This becomes the value of the ORIGIN keyword in the FITS headers If a null value is given it defaults to Starlink Software OUT LITERAL Write The names for the output FITS files These may be enclosed in double quotes and specified as a list of comma separated names or they may be created automatically on the basis of the input NDF names To do this the string supplied for this parameter should include an asterisk This character is a token which represents the name of the corresponding input NDF but with a file type of fit instead of sdf and SUN 55 31 Specifications of CONVERT Applications 60 NDF2FITS with no directory specification Thus simply supplying for this parameter will create a group of output files in the current directory with the same names as the input NDFs but with file type fit You can also specify some simple editing to be performed For instance new fit fits will add the string new to the start of every file name and will substitute the string fits for the original string fit NDF2FITS will not permit you to overwrite an existing FITS file unless you supply an exclamation mark prefix suitably escaped if you are using a UNIX shell PROEXTS LOGICAL Read If TRUE the NDF extensions other than the FITS extension are propa
126. rent value or 132 if there is no current value Examples ndf2ascii cluster cluster dat This copies the data array of the NDF called cluster to a text file called cluster dat The maximum recordlength of cluster dat is 132 bytes and the data values are packed into these records as efficiently as possible ndf2ascii cluster cluster dat v This copies the variance of the NDF called cluster to a text file called cluster dat The maximum recordlength of cluster dat is 132 bytes and the variance values are packed into these records as efficiently as possible ndf2ascii cluster cluster dat fixed noperec 12 This copies the data array of the NDF called cluster to a text file called cluster dat There are twelve data values per record in cluster dat ndf2ascii out ndf234 dat fits reclen 80 in 234 This copies the data array of the NDF called 234 to a text file called ndf234 dat The maximum recordlength of ndf234 dat is 80 bytes and the data values are packed into these records as efficiently as possible If there is a FITS extension it is copied to ndf234 dat with substitution of certain keywords otherwise a minimal FITS header is produced Notes The details of the conversion are as follows e the NDF array as selected by COMP is written to the ASCII file in records following an optional header When FIXED is FALSE all records are padded out to the recordlength e The NDF array elements are written in Fortran order i e the f
127. rmatted file spectrum to the NDF called zz The input file contains two header records that are ignored The NDF is one dimensional comprising 200 elements of type _REAL There is one data record containing the whole array unf2ndf spectrum lis ZZ skip 1 fits noperec 20 This copies a data array from the unformatted file spectrum lis to the NDF called ZZ The input file contains one header record that is ignored followed by a 91 UNF2NDF SUN 55 31 Specifications of CONVERT Applications FITS like header section which is copied to the FITS extension of the NDF The shape of the NDF is controlled by the mandatory FITS keywords NAXIS AXIS1 AXISn and the data type by keywords BITPIX and UNSIGNED Each data record has AXIS1 values except perhaps for the last Notes The details of the conversion are as follows e the unformatted file array is written to the NDF array as selected by COMP When the NDF is being modified the shape of the new component must match that of the NDF e If the input file contains a FITS like header and a new NDF is created i e COMP Data the header records are placed within the NDF s FITS extension This enables more than one array input file to be used to form an NDF Note that the data array must be created first to make a valid NDE and it s the FITS structure associated with that array that is wanted Indeed the application prevents you from doing otherwise e The FITS like header defi
128. rom the input file Preceding the input data there may be an optional header This header may be skipped or may consist of a simple FITS header In the former case the shape of the NDF has be to be supplied Usage ascii2ndf in out comp skip shape type Parameters COMP LITERAL Read The NDF component to be copied It may be Data Quality or Variance To create a variance or quality array the NDF must already exist Data FITS LOGICAL Read If TRUE the initial records of the formatted file are interpreted as a FITS header with one card image per record from which the shape data type and axis centres are derived The last record of the FITS like header must be terminated by an END keyword subsequent records in the input file are treated as an array component given by COMP FALSE IN FILENAME Read Name of the input text Fortran file The file will normally have variable length records when there is a header but always fixed length records when there is no header The maximum record length allowed is 512 bytes MAXLEN INTEGER Read The maximum record length in bytes of records within the input text file Unless the records are longer than 512 bytes you can use the default value The suggested value is the current value 512 OUT NDF Read and Write Output NDF data structure When COMP is not Data the NDF is modified rather than a new NDF created It becomes the new current NDF SHAPE _INTEGER Read
129. s system equispec The NDF title label units are written to the header keywords TITLE OBJECT and BUNIT respectively if they are defined Otherwise any values for these keywords found in the FITS extension are used provided Parameter PROFITS is TRUE There is a limit of twenty characters for each The NDF pixel origins are stored in keywords LBOUNDnz for the nth dimension when any of the pixel origins is not equal to 1 Keywords HDUCLAS1 HDUCLASz are set to NDF and the array component name respectively The BLANK keyword is set to the Starlink standard but only for the _WORD data type and not for a quality array It appears regardless of whether or not there are bad values actually present in the array HISTORY headers are propagated from the FITS extension when PROFITS is TRUE and from the NDF HISTORY component when PROHIS is TRUE If there is a FITS extension in the NDF then the elements up to the first END keyword of this are added to the user area of the IRAF header file when PROFITS TRUE However certain keywords are excluded SIMPLE NAXIS NAXISn BITPIX EX TEND PCOUNT GCOUNT BSCALE BZERO END and any already created from standard components of the NDF listed above A HISTORY record is added to the IRAF header file indicating that it originated in the named NDF and was converted by NDF2IRAF All other NDF components are not propagated 75 NDF2IRAF SUN 55 31 Specifications of CONVERT Applications Rel
130. s as follows SUN 55 31 Specifications of CONVERT Applications 36 FITS2NDF LSANFLX Data array label and units LSANFLXU Data errors hence variance LSANDET Quality bits 1 to 4 LSANSDIR Quality bit 5 LSANRPID Axis centres labels and units x y positions dimen sions 1 and 2 LSANSCNT Axis centre label and unit scan count index dimension 4 LSANWAV Axis centre label and unit wavelength dimension 3 LSANWAVU Axis errors wavelength dimension 3 LSANFILL not copied remaining columns column name in LWSAN extension e ISO SWS auto analysis SWS AA The conversion from binary table columns to NDF objects is as follows SWAAWAVE Axis centres label and units SWAAFLUX Data array label and units SWAASTDV Data errors hence variance SWAADETN Quality SWAARPID not copied SWAASPAR not copied remaining columns column name in SWSAA extension e AAO 2dF The conversion is restricted to a 2dF archive FITS file created by task NDF2FITS FITS2NDF restores the original NDF It creates the 2dF FIBRES extension and its constituent structures and NDF_CLASS extension In addition the variance axes and HISTORY records are converted The HISTORY propagation assumes that the FITS HISTORY headers have not been tampered Details of the conversion are The primary data array becomes the NDF s data array Any NaN values present become bad values in the NDF The keywords CRVALn CDELTn CRPIXn CTYPEn
131. s converts the GIF file horse gif into an NDF called horse in file horse sdf Notes The following points should be remembered e This initial version of the script generates images with at most 256 grey levels It does not use the image colour lookup table e Input image filenames must have the file extension gif e The NETPBM utilities giftopnm ppmtopgm pnmflip and pnmtofits must be available on your PATH Related Applications CONVERT INDF2GIF 41 IRAF2NDF SUN 55 31 Specifications of CONVERT Applications IRAF2NDF Converts an IRAF image to an NDF Description This application converts an IRAF image to an See the Notes for details of the conversion Usage iraf2ndf in out Parameters IN LITERAL Read The name of the IRAF image Note that this excludes the imh file extension OUT NDF Write The name of the NDF to be produced PROFITS LOGICAL Read If TRUE the user headers of the IRAF file are written verbatim to the NDF s FITS extension Any IRAF history records are also appended to the FITS extension The FITS extension is not created if there are no user headers present in the IRAF file TRUE PROHIS __LOGICAL Read This parameter decides whether or not to create NDF HISTORY records Only the IRAF headers with keyword HISTORY and which originated from NDF HISTORY records are used If PROHIS TRUE NDF HISTORY records are created TRUE Examples iraf2ndf ell_galaxy new_galaxy Converts
132. s follows SUN 55 31 Specifications of CONVERT Applications 46 IRCAM2NDF IRCAM file NDF Comments OBS PHASEA DATA_ ARRAY DATA ARRAY when Parameter CON FIG STARE OBS PHASEB DATA_ ARRAY gt DATA_ ARRAY when Parameter CON FIG CHOP OBS KTCA DATA_ ARRAY gt DATA_ARRAY when Parameter CON FIG KTCSTARE OBS KTCB DATA_ARRAY gt DATA_ARRAY when Parameter CON FIG KTCCHOP OBS DATA_LABEL gt LABEL OBS DATA_UNITS gt UNITS OBS TITLE gt TITLE If OBS TITLE is a blank string OBS DATA_OBJECT is copied to the NDF title instead OBS AXIS1_ LABEL gt AXIS 1 LABEL OBS AXIS2_LABEL gt AXIS 2 LABEL OBS AXIS1_UNITS gt AXIS 1 UNITS OBS AXIS2_ UNITS gt AXIS 2 UNITS IRCAM file NDF Comments GENERAL INSTRUMENT PLATE_SCALE becomes the in crement between the axis centres with co ordinate 0 0 0 0 located at the image centre The NDF axis units both become arcseconds GENERAL gt MORE IRCAM GENERAL GENERAL x gt MORE JRCAM GENERAL x GENERAL x y MORE IRCAM GENERAL x y OBS x gt MORE IRCAM OBS x This excludes the components of OBS already listed above and DATA_BLANK 47 IRCAM2NDF SUN 55 31 Specifications of CONVERT Applications e The data types of the IRCAM GENERAL structures have not been propagated to the NDF IRCAM extensions because it would violate the rules of SGP 38 In the IRCAM file these all have the same type STRU
133. s to make equivalent modifications to the others If a null parameter value is supplied for ENCODINGS then an attempt is made to determine the most reliable encoding to use as follows If both native and non native encodings are available then the first non native encoding to be found which is inconsistent with the native encoding is used If all encodings are consistent then the native encoding is used if present EXTABLE FILE Read This specifies the name of a text file containing a table associating sub files from a multi extension FITS file with specific NDF components If the null value is given for EXTABLE FITS sub files are treated as determined by the PROEXTS parameter see below SUN 55 31 Specifications of CONVERT Applications 24 FITS2NDF An EXTABLE file contains records which may be e component specifier records which associate FITS sub files with NDF compo nents e NDFNAMES records which specify the names of the NDFs to be created Normally they will be created within the top level HDS container file specified by the OUT parameter e directive records which inform the table file parser Spaces are allowed between elements within records and blank records are ignored Component specifier records have the form component sub file_specifiers transformation_code where e component case insensitive specifies the NDF component and is DATA VARIANCE QUALITY or EXTNi name The
134. scription of the CONTAINER parameter of FITS2NDF E 3 2 Release Notes V1 3 6 FITS2NDF e Improve error reporting if no WCS encoding can be used e Don t handle WCS if NDIM less than or 0 e Correct handling of NDF history records in the FITS header E 4 Release Notes V1 4 Added application MTFITS2NDFi to convert FITS tapes to NDFs E 4 1 Release Notes V1 4 1 Updated the IDL converters to work with IDL 5 5 Fix a problem causing a crash on Linux and document the fact that the Starlink IDL converters cannot be used with the 64 bit Solaris version of IDL Corrected an error in the section of this document describing the easy way to do IDL NDF conversions WRITE_NDF was described as if it were a function rather than a procedure E 4 2 Release Notes V1 4 2 Parameter WCSATTRS is added to FITS2NDF This enables users to modify the way WCS information is extracted from the FITS headers This can be useful when the headers do not conform to conventions E 4 3 Release Notes V1 4 3 Fixed a problem in NDF2FITS caused by a mismatch of conventions used in the TFORMn and TDIMn header cards for multi dimensional character arrays A corresponding fix was required for FITSZ2NDE E 4 4 Release Notes V1 4 4 Fixed a bug in FITS2NDF caused by a missing END card on a merged header 109 E 5 Release Notes V1 5 SUN 55 31 Release Notes E 5 Release Notes V1 5 SPECX2NDF has been revamped so that it now uses
135. se the CFITSIO library FITS2NDF will now report an error but continue to create the output NDF if an error occurs in creating history records It will also display warnings if it finds projections which include unsupported IRAF extensions A problem causing error FTPSCL Error defining the scale and offset when running NDEF2FITS has been corrected TRAF release V2 11 3 libraries are used in this release for building NDF2IRAF and RAF2NDF This document has been updated to include this section and a copyright statement Some bugs in the HTML version header have been corrected E 3 Release Notes V1 3 2 Two new converters HDS2IDLjand IDL2HDS are provided for IDL users They handle complete structures unlike READ_NDFjand WRITE_NDF which only handle the main arrays of NDFs NDEF2FITS and FITS2NDF have been enhanced by the addition of FITS AIPS and FITS PC encodings Also appropriate messages are output if there are no valid input files FITS2NDF has also been enhanced to allow more flexibility over the handling of multi extension FITS files Syntax such as filename fit 1 or filename fit extname im2 can be used to specify a single FITS extension to be converted and additional parameters EXTABLE and CONTAINER allow FITS extensions to be combined to produce a single NDF or a series of components of a top level HDS container file The scripts associated with the NDF on the fly conversion system have been modified to allo
136. t a prompt then place a at the end of each line where a continuation line is desired WCSATTRS LITERAL Read A comma separated list of keyword value pairs which modify the way WCS informa tion is extracted from the FITS headers Each of the keywords should be an attribute of an AST FitsChan This is the object which is responsible for interpreting the FITS WCS headers and is described full in the documentation for the AST library see SUN 210 For instance to force CAR projections to be interpreted as simple linear mappings from pixel co ordinates to celestial co ordinates rather than the non linear mapping implied by the FITS WCS conventions use WCSATTRS CarLin 1 A null value results in all attributes using default values WCSCOMP LITERAL Read This requests where co ordinate information is stored in the NDF for arbitrary FITS files FITS files from certain sources see Special Formats below adopt their own conventions such as always creating AXIS structures and not WCS thus ignore this parameter The allowed values are as follows e Axis Writes co ordinates of each element in the AXIS structure e WCS Stores co ordinate information in the WCS component e Both Writes co ordinate information in both the AXIS and WCS components e None Omits co ordinate information WCS is the recommended option as it offers most flexibility and many facilities such as transformations between co ord
137. t an container file containing an array of one dimensional NDFs holding SPECX spectra into a similar container file holding individual scalar NDFs each holding a single spectrum from the supplied array In both cases WCS components are added to the output NDFs describing the spectral and spatial axes A VARIANCE component is added to the output NDF that has a constant value derived from the Tsys value integration time and channel spacing in the input Usage specx2ndf in out gridfile telescope latitude longitude Parameters AXIS LOGICAL Read AXIS structures will be added to the output NDF if and only if AXIS is set TRUE FALSE GRIDFILE LITERAL Read The name of a text file to which a schematic of the SPECX map will be written This schematic shows those positions in the map grid where spectra were observed To indicate that a file containing the schematic is not to be written reply with an exclamation mark See Section Schematic of the map grid below for further details IN NDF Read The name of the input SPECX map or container file The file file extension sdf should not be included since it is appended automatically by the application LATITUDE LITERAL Read The geodetic geographic latitude of the telescope where the observation was made The value should be specified in sexagesimal degrees with a colon to separate the degrees minutes and seconds and no embedded spaces Values in
138. the IRAF image ell_galaxy comprising files ell_galaxy imh and ell_galaxy pix to an NDF called new_galaxy iraf2ndf ell_galaxy new_galaxy noprofits noprohis As above except no FITS extension is created and NDF style HISTORY lines in ell_galaxy imh are not transferred to HISTORY records in NDF new_galaxy Notes The rules for the conversion are as follows e The NDF is created with bounds determined by any LBOUNDn keywords in the IRAF image header e The NDF data array is copied from the pix file SUN 55 31 Specifications of CONVERT Applications 42 IRAF2NDF The title of the IRAF image object i_title in the imh header file becomes the NDF title Likewise headers OBJECT and BUNIT become the NDF label and units respectively The pixel origin is set if any LBOUNDzn headers are present Lines from the IRAF image header file may be transferred to the FITS extension of the NDF when PROFITS TRUE Any compulsory FITS keywords that are missing are added Certain other keywords are not propagated These are the IRAF Mini World Co ordinate System MWCS keywords WCSDIM DC_FLAG WATd_nnn d is dimension nnn is the line number Certain NDF style HISTORY lines in the header are also be ignored when PROHIS TRUE see two notes below When PROFITS TRUE lines from the HISTORY section of the IRAF image are also extracted and added to the NDF s FITS extension as FITS HISTORY lines Two extra HISTORY lines are added to record t
139. tions as storing it as a UNIX unformatted file where the image might subsequently be read in from disc in one go 95 B 2 Other Methods SUN 55 31 Handling NDFs in IDL It should be remembered that the data type of the F77 unformatted file created by NDF2UNF may differ depending on the type of data stored in the original NDF If this is the case you might need to change the type definition of the arrays image and temp to reflect this The data type used within each component of an NDF may be determined using NDFTRACE B 2 3 Using the IDL Astronomy Users Library If this all seems a bit tedious then those of you with with the IDL Astronomy Users Li brary installed on your machines might choose to take advantage of its FITS conversion pro cedures to make life easier still Users wishing to obtain a copy of the library can find it at http idlastro gsfc nasa gov homepage html The library contains IDL procedures from a number of sources that allow FITS format files to be read into IDL data structures The routine chosen for the example below was FXREAD which may be found in the pro bintable sub directory It is part of a comprehensive suite of FITS conversion programs that seems particularly easy to use So if you first convert your NDF into a FITS file using NDF2FITS like this ndf2fits in m42 out m42 fit comp d you can then use the following code from within IDL to place the image into an IDL structure and display it Read
140. tructures is written to the FITS like headers For example if a linear AXIS 1 structure exists in the input NDF the value of the first data point is stored with the keyword CRVAL1 and the incremental value between successive axis data is stored in keyword CDELT1 By definition the reference pixel is 1 0 and is stored in keyword CRPIX1 If there is an axis label it is written to keyword CTYPE1 and axis unit is written to CUNIT1 Similarly for AXIS 2 structures etc FITS does not have a standard method of storing axis widths and variances so these NDF components will not be propagated to the header Non linear axis data arrays cannot be represented by CRVALn and CDELTn and must be ignored If the input NDF contains TITLE LABEL or UNITS components these are stored with the keywords TITLE LABEL or BUNIT respectively If the input NDF contains a FITS extension the FITS items may be written to the FITS like header with the following exceptions BITPIX is derived from the type of the NDF data array and so it is not copied from the NDF FITS extension x NAXIS and NAXISn are derived from the dimensions of the NDF data array as described above so these items are not copied from the NDF FITS extension x The TITLE LABEL and BUNIT descriptors are only copied if no TITLE LABEL and UNITS NDF components respectively have already been copied into these headers SUN 55 31 Specifications of CONVERT Applications 82 NDF2UNF T
141. uired for each file conversion but in some cases inputs may be defined as GROUPS of names including wildcards see the application specifications for details 2 4 Obtaining Help You can get the top level help information for CONVERT by typing conhelp from the UNIX shell or ICL gt CONHELP from ICL You can also access CONVERT help from ICL by using the ICL command HELP The help topics are mostly detailed descriptions of the applications but also include global information on matters such as using parameters e g the following command gives help on the application UNF2NDF conhelp unf2ndf If you have commenced running an application you can still access the help library whenever you are prompted for a parameter you enter Here is an example NOPEREC Number of data values per output record 512 gt NDF2UNF Parameters NOPEREC _INTEGER Read The number of data values per record of the output file It should be in the range 1 to 8191 unless the array is double precision when the upper limit is 4095 The suggested default is the current value The first dimension of the NDF NOPEREC Number of data values per output record 512 gt 7 SUN 55 31 Automatic Format Conversion with the NDF Library 2 5 Hypertext Help A modified version of this document exists in hypertext form One way to access it is to use the command showme sun55 and a Web browser will appear presenting the ind
142. ull value requests no AXIS information be stored unless the current NDF contains AXIS information but no WCS An explicit TRUE or FALSE selection demands the chosen setting irrespective of how the current NDF stores co ordinate information Examples ndf2fits horse logo fit d This converts the NDF called horse to the new FITS file called logo fit The data type of the FITS primary data array matches that of the NDF s data array The FITS extension in the NDF is merged into the FITS header of logo fit 61 NDF2FITS SUN 55 31 Specifications of CONVERT Applications ndf2fits horse logo fit d proexts This converts the NDF called horse to the FITS file called logo fit An existing logo fit will be overwritten The data type of the FITS primary data array matches that of the NDF s data array The FITS extension in the NDF is merged into the FITS header of logo fit In addition any NDF extensions apart from FITS are turned into binary tables that follow the primary header and data unit ndf2fits horse logo fit noprohis This converts the NDF called horse to the new FITS file called logo fit The data type of the FITS primary data array matches that of the NDF s data array The FITS extension in the NDF is merged into the FITS header of logo fit Should horse contain variance and quality arrays these are written in IMAGE sub files Any history information in the NDF is not relayed to the FITS file ndf2fits data axz comp v
143. value Optional A value to replace in the IDL array any occurrence of the PRIMDAT bad value in the NDF component The value must be the same type as the array Keywords COMPONENT Set this to a string expression specifying the NDF component to be read It may be DATA VARIANCE or QUALITY and defaults to DATA The case of the string does not matter and it may be abbreviated to one or more characters Returned Value Result An IDL array of a size and type corresponding with the NDF The type correspon dence is as follows _REAL gt floating _DOUBLE gt double precision _UBYTE gt byte WORD gt integer _INTEGER gt longword integer Examples Assuming my_ndf sdf is an NDF of type _REAL IDL gt data_array read_ndf my_ndf creates an IDL floating array data_array with the same dimensions as the NDF and containing the values from its DATA component SUN 55 31 Specifications of CONVERT IDL Procedures 98 READ_NDF IDL gt data_array read_ndf my_ndf values f_nan As above except that any occurrence of a bad value VAL__BADR as defined by the Starlink PRIMDAT package in the NDF will be replaced by NaN in the IDL array IDL gt quality read_ndf my_ndf comp q creates an IDL byte array from the QUALITY component of the same NDF The QUALITY component is always type _UBYTE Note that the keyword component and the value QUALITY are case independent and can be a
144. w a single extension from a multi extension FITS file to be specified This feature requires applications to have been built with NDF V1 5 6 or later Different numbers of axes in the BaseFrames of the NDF and FitsChan FrameSets are now allowed when creating the NDF s WCS component NDF2FITS now uses the library to allow conversion of NDFs stored as sub components within an HDS container file e g scuba data etc TRAF release V2 11 3 libraries are used in this release for building NDF2IRAF and RAF2NDF This document has been updated to describe the new applications and enhancements and to include the IRAF Versions section Early release note sections have been removed On installation only a link to the installed ATEX document is now retained in the source directory SUN 55 31 Release Notes 108 E 4 Release Notes V1 4 E 3 1 Release Notes V1 3 5 FITS2NDF now creates a component of type FITS_HEADER not NDF in the container file for multi extension FITS files if the FITS HDU does not contain a data array NDF2FITS Corrects a problem with NDF2FITS if there is garbage beyond the END header record in the NDF s FITS airlock and stops a second ORIGIN header being output copied from the airlock if the ORIGIN parameter has been used to specify a non default ORIGIN NDF2PGM A bug which caused the image to be offset by three bytes has been fixed This document has been updated to include this section and to update the de
145. wer limits between which the image is to be scaled The application suggests the maximum and the minimum values minimum values when prompting e Sigmas The image is scaled between two standard deviation limits Range SIGMAS 2 _REAL Read Only required if SCALE is Sigmas The standard deviation bounds that define the scaling limits To obtain values either side of the mean both a negative and a positive value are required Thus 2 3 would scale between the mean minus two and the mean plus three standard deviations 3 2 would give the negative of that Results Parameters SCAHIGH _DOUBLE Write The array value scaled to the maximum colour index for display SCALOW _DOUBLE Write The array value scaled to the minimum colour index for display Examples ndf2gif old new This converts the NDF called old in file old sdf into a GIF file new gif ndf2gif horse scale pe This converts the NDF called horse in file horse sdf into a GIF file horse gif using percentile scaling The user will be prompted for the percentiles to use Notes The following points should be remembered e This initial version of the script generates only 256 grey levels and does not use the image colour lookup table so absolute data values may be lost SUN 55 31 Specifications of CONVERT Applications 72 NDF2GIF e The NETPBM utilities tifftopnm and ppmtogif must be available on your PATH Related Applications CONVERT
146. word COMPONENT and the value VARIANCE are case independent and can be abbreviated Deficiencies No conversion of the given bad value to the appropriate type for the array will be at tempted instead an error will be reported Related Applications CONVERT READ_NDF SUN 55 31 Specifications of CONVERT IDL Procedures 102 ADS2IDL HDS2IDL Convert a Starlink HDS file to an IDL variable Description This function will convert a Starlink HDS object into an IDL variable The object may be a structure or primitive so a complete NDF structure can be obtained instead of just the single component produced by function READ_NDF Usage Result HDS2IDL filename Arguments filename A string expression specifying an HDS object The specification may include slices and cells of arrays Returned Value Result An IDL variable corresponding to the HDS object Structures and primitive types are not necessarily identical see Notes Notes e Type correspondence is as follows _REAL gt floating _DOUBLE gt double precision _UBYTE gt byte WORD gt integer _INTEGER gt longword integer _LOGICAL gt longword integer with name change see below _CHAR gt string see below _BYTE gt integer see below _UWORD gt longword integer see below e IDL structures will have an additional STRING component named HDSSTRUCTYPE specifying the type of the HDS structure to which it corresponds e _LOG
147. x2NDF commands If you wish that all new NDFs created by CONVERT have history recording enabled at their creation you should set the environment variable NDF_AUTO_HISTORY to a non zero integer value In fact we recommend that you set this in your login script so any NDF created from scratch will have this property 5 Acknowledgments Jo Murray wrote the original versions of the applications that convert between DSTs and NDFs Alan Chipperfield produced the IDL converters Rhys Morris wrote the original versions of IRAF2NDF NDF2IRAF GASP2NDF and NDF2GASP Grant Privett wrote the TIFF and 3This was because at the time it was created history records could potentially be quite bulky for spectra SUN 55 31 Acknowledgments 10 contributed to the GIF conversion utilities Clive Davenhall wrote AST2NDF and SPECX2NDF the latter was substantially revised by David Berry to work with the AST SpecFrame Rodney Warren Smith devised the format conversion facilities for the NDF data access library and Alan Chipperfield implemented the CONVERT components of it 11 SUN 55 31 Specifications of CONVERT Applications A Specifications of CONVERT Applications A 1 Explanatory Notes The Parameters section lists the application s parameters with the format name type access description The description entry has a notation scheme to indicate normally defaulted parameters i e those for which there will be no prompt For such parameters a m
148. y and linear axis centres then it should be possible to avoid loss of information except with GIF and TIFF formats which will reduce the absolute data values to 256 greyscale levels Note the input data file is not deleted or altered in any way SUN 55 31 Running CONVERT 4 2 Running CONVERT 2 1 Starting CONVERT from the UNIX shell The command convert defines CONVERT commands from the UNIX shell convert Note that the is the UNIX shell s prompt which you do not type A message similar to CONVERT commands are now available Version 1 0 1997 August Defaults for automatic NDF conversion are set Type conhelp for help on CONVERT commands Type showme sun55 to browse the hypertext documentation will be displayed You will then be able to mix CONVERT and UNIX commands The convert command is defined by the Starlink startup procedures to source file convert csh in the CONVERT executables directory Non Starlink sites must make their own arrangements 2 2 Starting CONVERT from ICL To start ICL type A icl You will see any messages produced by system and user procedures followed by the ICL gt prompt something like the following ICL UNIX Version 3 1 5 20 05 97 Loading installed package definitions Type HELP package_name for help on specific Starlink packages or HELP PACKAGES for a list of all Starlink packages Type HELP command for help on ICL and its commands ICL gt

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CONVERT – A Format-conversion Package