Our GRASS 4.1 mods.

Donald Newcomb newcomb at navo.hpc.mil
Tue May 5 03:02:42 EDT 1998

Thanks for the pointer to the Baylor U. GRASS site. Years ago I was
active in the GRASS steering committee but got "reorganized" and had to
drop out. For the last few years we've been conducting our own
development based on GRASS 4.1, without much reference to the outside
world. One of the mods made by our staff has been a modification of the
raster categories to permit either the normal category table or a linear
scaling. This came about because we found that raster files representing
continuous surfaces (e.g. density values from 1.00 gm/cc to 5.00 gm/cc)
took far too long to access in a production environment. We now have a
program called "r.modcats" which works like this:

r.modcats  elevation <<EOF
title:Elevation (10 meter resolution)
auto:$1 to $2 meters
c1:10.0 -9.0
0:Sea Level

This would generate the following title and categories:

Elevation (10 meter resolution)
0) Sea Level
1) 1 to 10 meters
2) 11 to 20 meters

However, the category file does not contain the categories but rather,
just the rules for generating them. 

If this is not already in GRASS we probably ought to find a way to
contribute it to the effort.

Donald R. Newcomb              * newcomb at navo.hpc.mil         
Naval Oceanographic Office     * newcombd at navo.navy.mil
Stennis Space Center, MS 39522 * Voice: (228) 688-5998
FAX: (228) 688-5485            * DSN: 485-5998

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