spottopgm (1)

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 LITTLE\_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 therefore 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