NAME

       pamtofits - convert a Netpbm image into FITS format

SYNOPSIS

       pamtofits [-max f] [-min f] [pamfile]

DESCRIPTION

       This program is part of Netpbm(1).

       pamtofits  reads a PNM or PAM 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).

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩ ), pamtofits recognizes the following command
       line options:

       -min and -max tell pamtofits  what  "physical  values"  zero  and  maxval  sample  values,
       respectively,  in  the  input  image  represent.   Physical  values  are  a  FITS concept.
       pamtofits 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 Netpbm sample values.

       pamtofits  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 Netpbm maxval and  the
       lowest  is  that  corresponding  to  Netpbm  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.

NOTES

   Pixel Order
       The  FITS specification does not specify which data in the file corresponds to which pixel
       in the image (i.e. which bytes are the top left pixel,  etc.).   Netpbm  uses  the  common
       sense, most popular arrangement: row major, top to bottom, left to right.  That means in a
       10 wide by 20 high image, the first 10 pixels in the file are the top row and the last  10
       are  the  bottom  row.   Within each row, the first pixel is the leftmost one and the last
       pixel is the rightmost one.

       Netpbm has always done that, since it first understood the FITS format in 1989, so  it  is
       something of a de facto standard.  Nobody reported trouble with that until 2008.

       However,  at  least  some versions of ImageMagick and Gimp (as seen in 2008) use bottom to
       top order, so if you use on of these to display a FITS image generated  by  pamtofits,  it
       will  appear upside down.  To fix that, use pamflip -topbottom on the image before feeding
       it to pamtofits.

       Since 2008, people have noted that NASA distributes FITS files with bottom to top order.

HISTORY

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

       pnmtofits was itself an extension of pgmtofits, which was added to Pbmplus in 1989.

SEE ALSO

       fitstopnm(1), pam(1)

AUTHOR

       Copyright  (C)  1989  by Wilson H. Bent (whb@hoh-2.att.com), with modifications by Alberto
       Accomazzi (alberto@cfa.harvard.edu).

DOCUMENT SOURCE

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master
       documentation is at

              http://netpbm.sourceforge.net/doc/pamtofits.html