SYNOPSISpnmtofits [-max f] [-min f] [pnmfile]
DESCRIPTIONReads a portable anymap as input. Produces a FITS (Flexible Image Transport System) file as output. The resolution of the output file is either 8 bits/pixel, or 16 bits/pixel, depending on the value of maxval in the input file. If the input file is a portable bitmap or a portable graymap, the output file consists of a single plane image (NAXIS = 2). If instead the input file is a portable pixmap, the output file will consist of a three-plane image (NAXIS = 3, NAXIS3 = 3). A full description of the FITS format can be found in Astronomy & Astrophysics Supplement Series 44 (1981), page 363.
Flags -min and -max can be used to set DATAMAX, DATAMIN, BSCALE and BZERO in the FITS header, but do not cause the data to be rescaled.
FITS uses signed data, and this program outputs unsigned values. If you run into this problem, you might use "-min 32768".