This Bourne-shell script converts a Graphics Interchange Format (GIF) file into an unsigned-byte (256 grey-level) NDF format file. It handles one- or two-dimensional images. The script uses various NETPBM utilities to produce a FITS file, flipped top to bottom, and then FITS2NDF to produce the final NDF. Error messages are converted into Starlink style (preceded by !).

IN = FILENAME (Read)

OUT = NDF (Write)

gif2ndf old new

This converts the GIF file old.gif into an NDF called new (in file new.sdf).

gif2ndf horse

This converts the GIF file horse.gif into an NDF called horse (in file horse.sdf).

The following points should be remembered:

• This initial version of the script generates images with at most 256 grey levels. It does not use the image colour lookup table.

• Input image filenames must have the file extension .gif.

• The NETPBM utilities giftopnm, ppmtopgm, pnmflip and pnmtofits must be available on your PATH.

Convert: NDF2GIF.