Updated: 25 September 2005
   Table Of Contents


   pnmtofits - convert a PNM image into FITS format


   pnmtofits [-max f] [-min f] [pnmfile]


   This program is part of Netpbm.

   pnmtofits  reads  a  PNM  image  as  input and 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 PBM or PGM  image,  the
output file
   consists  of  a single plane image (NAXIS = 2). If instead the
input file is a
   PPM image, the output file will consist of a three-plane image
(NAXIS = 3,
   NAXIS3 = 3).

   You  can  find  a  full  description of the FITS format in As-
tronomy &
   Astrophysics Supplement Series 44 (1981), page 363.


   -min and -max tell pnmtofits what "physical values"  zero  and
maxval sample
   values,  respectively,  in the input image represent. Physical
values are a
   FITS concept. pnmtofits sets up  the  BSCALE  and  BZERO  FITS
header cards to
   indicate this information.

   The  default  for  -min is 0 and for -max is the maxval, which
means if you
   don’t  specify these options, the FITS physical values are  in
fact the
   original PNM sample values.

   pnmtofits   always sets up the FITS header DATAMIN and DATAMAX
cards to
   indicate  that  the  highest  physical  value  in the image is
the one
   corresponding  to the PNM maxval and the lowest is that corre-
sponding to PNM
   zero. This isn’t really how those cards  are  supposed  to  be
used, since the
   input  image  doesn’t  necessarily  contain  the full possible
range of sample
   values. It is a conservative approximation.


   pamtofits was originally pnmtofits and did not handle PAM  in-
put. It was
   extended and renamed in Netpbm 10.30 (October 2005).


   fitstopnm, pnm


   Copyright (C) 1989 by Wilson H. Bent (, with
   by Alberto Accomazzi (

Table Of Contents

     * NAME
     * OPTIONS
     * HISTORY
     * SEE ALSO
     * AUTHOR

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