[R-sig-Geo] Flow accumulation in R?

[Jonathan Greenberg]

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try to compile, although it seems to be fairly out of date.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).

topidx looked interesting but I can tell that it won't scale -- it
requires the image be in memory as a matrix, so any reasonably large
DEM won't work.

Sounds like this may require some programming!

--j



On Thu, Sep 29, 2011 at 6:02 AM, Rich Shepard <rshepard at appl-ecosys.com> wrote:
> On Wed, 28 Sep 2011, Jonathan Greenberg wrote:
>
>> I was wondering if anyone had implemented flow accumulation in R (e.g.
>> http://www.cs.duke.edu/geo*/terraflow/)?
>
> Jon,
>
>  I use r.terraflow (and other hydrological modules) within GRASS
> <http://grass.osgeo.org/>. Terrain and hydrologic modeling is best done, in
> my opinion, in GRASS and leave the spatial statistics to R. There is an
> interface between the two that allows us users to take advantage of both.
>
> Rich
>
> --
> Richard B. Shepard, Ph.D.          |   Integrity - Credibility - Innovation
> Applied Ecosystem Services, Inc.   |    Helping Ensure Our Clients' Futures
> <http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863
>



-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Department of Geography
University of Illinois at Urbana-Champaign
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