[GRASS5] Re: r.drain -- new version

Rich Shepard rshepard at appl-ecosys.com
Wed Jul 18 18:54:05 EDT 2001

On Thu, 19 Jul 2001, Markus Neteler wrote:

> many thanks for your cmoplete rewrite of r.drain - now it seems to
> run correctly! I have tested with FCELL and DCELL map.

Markus, Roger, et al.:

  I've been reading Taylor and Gallant's "Terrain Analysis: Principles and
Applications", which is based on the TAPES-G program (Terrain Analysis
Program for Environmental Sciences - Grid;
http://cres.anu.edu.au/outputs/tapes.html). I found a typo on two of the
figures (mis-labled) and wrote to the authors. John Gallant in Australia
wrote back and said that they'd like to test tape with a GIS, but he's not
used GRASS at all (but he's heard of it). So, I volunteered to test it for
them. I hope that we'll be able to incorporate it into GRASS if that's
considered desirable by all.

  While I'm on the topic of terrain analysis, let me ask this of the
community: why does it appear that so many modules overlap in function? For
example, r.slope.aspect, r.drain, r.flow, r.watershed (and others, most
likely) all have what appears to me to be either the same functionality (in
part), or they are so complementary that they should be aggregated into a
single module.

  What do y'all think? I'd really like to completely understand the
subtleties that distinguish each of these modules.


Dr. Richard B. Shepard, President

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