NAME
    spottopgm - convert SPOT satellite images to Portable Greymap format

SYNTAX
    spottopgm [-1|2|3] [Firstcol Firstline Lastcol Lastline] inputfile

OPTIONS
    -1|2|3 Extract the given colour from the SPOT image. The colours are
     infra-red, visible light and ultra-violet, although I  don't
     know which corresponds  to which number. If the image is in
     colour, this will be announced on standard error. The default
     colour is 1.

    Firstcol Firstline Lastcol Lastline
     Extract the specified rectangle from the SPOT image. Most SPOT
     images are 3000 lines long and 3000 or more columns  wide.
     Unfortunately the SPOT format only gives the width and not the
     length. The width is printed on standard error. The default
     rectangle is the width of the input image by 3000 lines.

DESCRIPTION
    Spottopgm converts the  named inputfile into Portable Greymap format,
    defaulting to the first color and the whole SPOT image unless specified
    by the options.

INSTALLATION
    You must edit the source program and either define BIG_ENDIAN or LIT-
    TLE_ENDIAN, and fix the typedefs for uint32_t, uint16_t and uint8_t
    appropriately.

BUGS
    Currently spottopgm doesn't determine  the length of the input file;
    this would involve two passes over the input file. It defaults to 3000
    lines instead.

    Spottopgm could  extract a three-color image (ppm), but I didn't feel
    like making the program more complicated than it is now. Besides, there
    is no one-to-one correspondence between red, green, blue and infra-red,
    visible and ultra-violet.

    I've only had a limited number of SPOT images to play with, and there-
    fore wouldn't guarantee that this will work on any other images.

AUTHOR
    Warren Toomey wkt@csadfa.cs.adfa.oz.au

SEE ALSO
    The rest of the Pbmplus suite.