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[fitsbits] [fitswcs] WCSLIB 3.3
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[fitsbits] [fitswcs] WCSLIB 3.3
Stephen Walton wrote:
Mark's announcement of WCSLIB 3.3 reminds me to ask a generic question about an issue I'm sure others have faced: how best to switch from an IRAF environment to a CFITSIO/WCSLIB one. While IRAF has served us well for 15 years, I don't see a huge effort being undertaken to bring its WCS library in compliance with the standard, nor to support other map projections beyond those already in place. As a solar astronomer I have other needs :-) . Most of my code is in Fortran, with just a few SPP "wrapper" main programs to get access to some of the IRAF IMIO routines. My WCSTools package supports all of Mark's projections (though I am still in the process of upgrading it from WCSLIB 2.9 to WCSLIB 3.3) and reads IRAF imh files as well as FITS files. I support the IRAF TNX projection, but haven't quite got around to implementing the IRAF ZPX projection. There are Fortran wrapper for the WCS subroutines, too. WCSTools has its own FITS code--I've been dealing with FITS for over 20 years--but the WCS subroutines are easily separated from the rest and are currently used by CFITSIO, as well as many of the popular astronomical image display programs. I am continuing to make an effort to support the evolving standard as well as legacy WCS formats, including most drafts of the FITS WCS papers. Multiple (and even chained) WCS's are supported, and I have starting implementing FITS-WCS Paper IV by providing distortion correction for SIRTF images. Documentation and source code are available at http://tdc-www.harvard.edu/software/wcstools/ -Doug Mink Telescope Data Center Smithsonian Astrophysical Observatory Cambridge, Massachusetts USA |
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[fitsbits] [fitswcs] WCSLIB 3.3
On Wed, 22 Oct 2003, Stephen Walton wrote: Mark's announcement of WCSLIB 3.3 reminds me to ask a generic question about an issue I'm sure others have faced: how best to switch from an IRAF environment to a CFITSIO/WCSLIB one. While IRAF has served us well for 15 years, I don't see a huge effort being undertaken to bring its WCS library in compliance with the standard, nor to support other map projections beyond those already in place. As a solar astronomer I have other needs :-) . Most of my code is in Fortran, with just a few SPP "wrapper" main programs to get access to some of the IRAF IMIO routines. You may be interested in the AST library which provides a high level interface for reading, writing, modifying and plotting generalised WCS information (including FITS-WCS of various flavours). It is callable from Fortran, C and (via JNI) from Java. See: http://www.starlink.ac.uk/ast/ David |
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[fitsbits] [fitswcs] WCSLIB 3.3
On Thu, 2003-10-23 at 08:48, Doug Mink wrote:
My WCSTools package supports all of Mark's projections (though I am still in the process of upgrading it from WCSLIB 2.9 to WCSLIB 3.3) and reads IRAF imh files as well as FITS files. Thanks for taking the time to answer, Doug. I do have one question: when you say WCSTools "reads IRAF imh files" does that mean it works with both the PC and CD matrix formalisms? -- Stephen Walton Dept. of Physics & Astronomy, Cal State Northridge |
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[fitsbits] [fitswcs] WCSLIB 3.3
On Wed, 2003-10-22 at 23:19, Mark Calabretta wrote:
The current plan regarding CFITSIO and WCSLIB is for Bill Pence to write a CFITSIO function which extracts the header into a char array, and for me to write a WCSLIB function which identifies and extracts all WCS cards from the header and returns an array of pointers to wcsprm structs This sounds really excellent. As someone who has a lot of images in the CD matrix format, though, may I politely request that Bill and/or your routines support the CD and PC matrices? Thanks much for all your work! -- Stephen Walton Dept. of Physics & Astronomy, Cal State Northridge |
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[fitsbits] [fitswcs] WCSLIB 3.3
On Fri 2003/10/24 11:55:37 MST, Stephen Walton wrote in a message to: Mark Calabretta and copied to: CD matrix format, though, may I politely request that Bill and/or your routines support the CD and PC matrices? WCSLIB already does, as of version 3.0, and also recognizes CROTAn in old header files. Likewise for the new parsing routine that I mentioned (when it eventually appears). Cheers, Mark |
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[fitsbits] [fitswcs] WCSLIB 3.3
Stephen Walton wrote:
On Thu, 2003-10-23 at 08:48, Doug Mink wrote: My WCSTools package supports all of Mark's projections (though I am still in the process of upgrading it from WCSLIB 2.9 to WCSLIB 3.3) and reads IRAF imh files as well as FITS files. Thanks for taking the time to answer, Doug. I do have one question: when you say WCSTools "reads IRAF imh files" does that mean it works with both the PC and CD matrix formalisms? WCSTools supports both PCi_j and CDi_j matrix formalisms, as well as the PC00i00j keywords which were in some of the early drafts of the FITS WCS papers. The order of preference, if for some reason multiple formalisms are present is CDi_j, PC00i00j, PCi_j, and finally CDELTi/CROTAi. If CTYPEi is not present, DSS keywords are checked; if they are not present, a non-rotated north-up, east-left TAN projection centered at RA,DEC at the center of the image, with a scale in arcseconds per pixel specified by any of several commonly used variations on SECPIX is initialized. WCSTools can read IRAF imh files created on any computer (IRAF characters in headers in old imh files are two byes and hence endian like the data in either of the two imh formats. -Doug Mink Telescope Data Center Smithsonian Astrophysical Observatory Cambridge, Massachusetts USA |
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[fitsbits] [fitswcs] WCSLIB 3.3
On Fri 2003/10/24 11:55:37 MST, Stephen Walton wrote in a message to: Mark Calabretta and copied to: CD matrix format, though, may I politely request that Bill and/or your routines support the CD and PC matrices? WCSLIB already does, as of version 3.0, and also recognizes CROTAn in old header files. Likewise for the new parsing routine that I mentioned (when it eventually appears). Just for completeness... the AST library (www.starlink.ac.uk/ast/) also handles CD (both CDi_j and CDiiijjj) and PC matrices (both PCi_j and PCiiijjj), and includes a parsing system (i.e. you give it an entire header, and it sucks out the bits it needs and gives you a pointer to an object representing all the WCS information in the header). David |
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[fitsbits] [fitswcs] WCSLIB 3.3
David Berry wrote:
Just for completeness... the AST library (www.starlink.ac.uk/ast/) also handles CD (both CDi_j and CDiiijjj) and PC matrices (both PCi_j and PCiiijjj), and includes a parsing system (i.e. you give it an entire header, and it sucks out the bits it needs and gives you a pointer to an object representing all the WCS information in the header). Since I didn't note it before, WCSTools also provides a single-call parsing subroutine which ingests a FITS header and returns a WCS structure or cascading WCS structures if the designated WCS depends on others. FITS reading software is also included--my FITS experience predates CFITSIO--so there is another single subroutien call which returns the WCS structure(s) given a FITS or IRAF .imh file name. -Doug Mink |
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