2011/9/29 Jonathan Greenberg <jgrn@illinois.edu>

> Thanks for the responses -- one of the issues with the GRASS
> implementation of terraflow is that there is not, to my knowledge,
> parallel support for the code -- the C++ version, I suppose, we can
> try to compile, although it seems to be fairly out of date.  I figured
> with the quickly increasing capabilities in spatial programming beyond
> just spatial statistics in R (e.g. via raster, rgdal, maptools), as
> well as other people developing parallel interfaces for R (e.g.
> snowfall, Rmpi), R may do well as a scalable system for doing large
> scale image processing/GIS analyses.  Certainly, other programs have
> not scaled well (ArcMap and GRASS to name a few).
>

you may have a look at the r.watershed module in GRASS, there were a lot of
improvment in the futur 7.0 version ...
but on the man page (
http://grass.osgeo.org/gdp/html_grass64/r.watershed.html), they say "The
algorithm produces results similar to those obtained when running
*r.cost<http://grass.osgeo.org/gdp/html_grass64/r.cost.html>
* and *r.drain <http://grass.osgeo.org/gdp/html_grass64/r.drain.html>* on
every cell on the map" so i think it should be not too difficult to write a
small script to parallelize the operation !



cheers,
Sylvain

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