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The following subroutines are provided to help calculate the
transformation between pixel location in an image and the corresponding
celestial coordinates on the sky. These support the following standard
map projections: -SIN, -TAN, -ARC, -NCP, -GLS, -MER, and -AIT (these
are the legal values for the coordtype parameter). These routines are
based on similar functions in Classic AIPS. All the angular quantities
are given in units of degrees. (Note: these subroutines are provisional
and may change slightly in a future release of FITSIO).
- 1
- Get the values of all the standard FITS celestial coordinate system
keywords from the header of a FITS image (i.e., the primary array or
an image extension). These values may then be passed to the subroutines
that perform the coordinate transformations.
FTGICS(unit, > xrval,yrval,xrpix,yrpix,xinc,yinc,rot,coordtype,status)
- 2
- Get the values of all the standard FITS celestial coordinate system
keywords from the header of a FITS table where the X and Y (or RA and
DEC coordinates are stored in 2 separate columns of the table.
These values may then be passed to the subroutines that perform the
coordinate transformations.
FTGTCS(unit,xcol,ycol, >
xrval,yrval,xrpix,yrpix,xinc,yinc,rot,coordtype,status)
- 3
- Calculate the celestial coordinate corresponding to the input
X and Y pixel location in the image.
FTWLDP(xpix,ypix,xrval,yrval,xrpix,yrpix,xinc,yinc,rot,
coordtype, > xpos,ypos,status)
- 4
- Calculate the X and Y pixel location corresponding to the input
celestial coordinate in the image.
FTXYPX(xpos,ypos,xrval,yrval,xrpix,yrpix,xinc,yinc,rot,
coordtype, > xpix,ypix,status)
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