NAME

fregcon -- region file converter from one instrument/detector to another

USAGE

        fregcon infil1 infil2 regfile outfile

DESCRIPTION

This task converts a selected region from one observation to another either based on the reference values contained in the FITS image files for the two observations or on a single multiplicative scale factor. The list of selected regions (up to 40) are specified in the regionfile (regfile). The region file is produced by SAOimage or SAOtng. Possible shapes for the regions are the following:

     *  circle
     *  box
     *  ellipse
     *  point
     *  polygon (up to 40 points)
     *  annulus

If the factor parameter is specified then the infil1 and infil2 are not required and the regions will be modified by scaling the image size by the value of the factor parameter.

The following reference keyword values read from the two input FITS image files. They are passed to the ftwldp.f and xy2sky.f routines which compute the new coordinates.

     CRPIX1  =  X axis reference pixel
     CRPIX2  =  Y axis reference pixel
     CRVAL1  =  Sky coord of X ref pixel (degrees)
     CRVAL2  =  Sky coord of Y ref pixel (degrees)
     CDELT1  =  X axis increment (degrees)
     CDELT2  =  Y axis increment (degrees)
     CROTA2  =  ROLL angle
     CTYPE1  =  RA projection 
     CTYPE2  =  DEC projection

PARAMETERS

infil1 [file name]

The first input FITS image file and extension number.

infil2 [file name]

The second input FITS image file and extension number.

regfile [file name]

The region file containing old region file data.

outfile [file name]

The output file containing new region file data.

factor [real]

The factor by which to increase the image scale for the region files. ie all region dimensions are multiplied by the value of factor and if the positions are in pixels then these too are multiplied.

BUGS

SEE ALSO

ftwldp.f xy2sky.f

CATEGORY