Documentation on regrid

Task: regrid
Purpose: Regrid an image dataset
Categories: map analysis

        REGRID regrids an image by spline fitting and resampling.  The
        regridding parameters can be specified by a template image, by
        axis descriptors, or by a start and end range.   Blanked input
        pixels are excluded from the interpolation arrays.  Extrapolated 
        output pixels are blanked.  Regridding of any combination of 
        the first three axes of an image is supported.

Key: in
        The input image name. No default.

Key: tin
        Input template image.  The axis descriptors of the regridded
        image, for those axes specified by keyword "axis", are those
        of the template image.
        Default is no template image.

Key: out
        The output image name.  No default.

Key: desc
        If "tin" is unset, then specify the reference value, reference
        pixel, pixel increment, and number of pixels for the axes 
        designated by keyword "axis" of the output image.  

        Note that for RA/DEC axes, the increments are in radians on 
        the sky. Thus, dRA = dX / cos(dec) and dDEC = dY where you 
        specify dX and dY.

        Defaults are no axis descriptors.

Key: range
        If "tin" and "desc" are unset, then specify the start coordinate
        value, end coordinate value and pixel increment for the axes
        designated by the keyword "axis" of the output image. The reference
        value of the output image will be the same as the input image, 
        and the reference pixel will be recomputed.

        Note that for RA/DEC axes, the increments are in radians on 
        the sky. Thus, dRA = dX / cos(dec) and dDEC = dY where you 
        specify dX and dY.  The start and end coordinates are directly
        RA and DEC in radians.
        
        Defaults are no ranges.

Key: axis
        Specify axes to regrid with a command such as axis=1,2 to regrid
        axes 1 and 2, or 2,3 to regrid axes 2 and 3.  No matter
        what order you specify axes in "axis", you MUST always give
        the axis descriptors in "desc" and "range" in monotonically 
        increasing axis order (e.g., 1,2,3 or 1,3 or 3 say).
        No default.

Key: options
        Task enrichment options.  Minimum match is active.

        nohog   If regridding the third axis, the program is quite
                expensive on disk and memory resources. It may not
        	be able to allocate the needed resources. This option
               offers a slower and less memory greedy method.
        relax   Only issue warnings rather than fatal errors if axis type
                mismatches between template and input files exist
        quiet   Don't give so many messages about what row its on etc.