[GRASS-user] Hydrological grass question: main channel length for each subbasin

Rich Shepard rshepard at appl-ecosys.com
Mon Feb 17 05:35:39 PST 2014

On Mon, 17 Feb 2014, Michel Wortmann wrote:

> this is what I meant by looping over each subbasin, but that is exactly
> what I would like to avoid as it would take a lot of time for 1000+
> subbasins and I dont really need all the other analysis.


   If you look at the code for that module you'll see that you cannot get
directly to the end without calculating all the intermediate values; one
attribute builds on those calculated before it. As long as the intermediates
are being calculated there's no reason to not put their results in the
overall table.

   If you want only main channel length for 1000+ subbasins you might figure
out a way to calculate that directly and modify the code (with a different
module name, of course) to do that. This is one of the advantages of open
source software licensed under the GPL.


Richard B. Shepard, Ph.D.          |      Have knowledge, will travel.
Applied Ecosystem Services, Inc.   |
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

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