[GRASS-user] Re: grass-user Digest, Vol 30, Issue 22

[Michael Barton]

Markus,

I thought this was already in the svn. Not?

Michael
______________________________
C. Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University
Tempe, AZ  85287-2402
USA

voice: 480-965-6262; fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

On Oct 9, 2008, at 9:00 AM, <grass-user-request at lists.osgeo.org> wrote:

> Date: Thu, 09 Oct 2008 16:38:40 +0200
> From: Markus Metz <markus_metz at gmx.de>
> Subject: [GRASS-user] r.watershed.fast new version
> To: grass-user at lists.osgeo.org
> Message-ID: <48EE1770.502 at gmx.de>
> Content-Type: text/plain; charset=ISO-8859-15
>
> Hi all,
>
> some time ago I posted a new version of r.watershed with substantial
> speed increase, but still with slight differences in the outputs
> compared to the original version. This problem is solved, whether or  
> not
> these differences in flow direction and flow accumulation were  
> critical.
> Now the results in flow direction and flow accumulation are 100%
> identical to the original version. All other outputs are based on flow
> direction and flow accumulation and therefore also identical.
>
> The speed increase for the ram version is the same as with my first
> version: e.g. a region with 22,500,000 cells is processed in 1minute 6
> seconds, the original version needs 10 hours. The modified seg version
> (-m flag set) needs 16 minutes (North Carolina sample data, elevation
> resampled to 3 m). No idea how long the original seg version needs for
> such a region, more than a day I guess.
>
> The source code of r.watershed.fast available here
> http://markus.metz.giswork.googlepages.com/r.watershed_fast_version.tar.gz
>
> If you give this modified version a try, please let me know if it  
> works
> or not, I tested it only on Linux 32bit and Linux 64bit.
>
> Markus