[AstroPy] AstroLibWCS & AstroLibCoords

Stephen Walton stephen.walton at csun.edu
Thu Apr 21 09:25:42 CDT 2005


Perry Greenfield wrote:

> On Apr 20, 2005, at 9:53 AM, Alexandre Beelen wrote:
>
>> I was also thinking to wrap the WCSLIB [2] using swig or something else,
>> does any of you tried this before ?
>>
> We've done that too. If you are interested we can make the wrappers 
> available. We decided to see if was just as easy to re-implement and 
> use wcslib for test comparisons. (And it turns out, that much of the 
> complexity of handling FITS WCS headers is not really handled by 
> wcslib; it basically presumes you have extracted the necessary set of 
> keywords for its use (if I recall correctly).

This is not as true as it used to be.  From a March 18 posting by 
William Pence to the fitswcs discussion group:

>1.  call the fits_hdr2str routine in CFITSIO to read the image header 
>keywords into a long character string variable.
>
>2.  pass this string variable to the wscpih routine in WCSLIB, which then 
>parses all the WCS keywords and creates internal structures that will be 
>used in subsequent transforms between pixel and world coordinates.
>
>3.  call the wcsp2s routine in WCSLIB to convert any input pixel coordinate 
>into world coordinates.

The complete archived message is at

http://listmgr.cv.nrao.edu/pipermail/fitswcs/2005-March/000334.html

Steve Walton




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