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 ), 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

netpbm documentation                            25 September 2005                       Pamtofits User Manual(1)