[R-sig-Geo] generating distance map for Large map

[Dylan Beaudette]

On Monday 21 July 2008, milton ruser wrote:
> Dear all,
>
> I have a very large BINARY image (60,000x50,000 pixels) and need to
> generate the distance map from the 1 values.
> When the images are small than my image, I can generate the distance map
> using ArcGis (my image is in .IMG format), but ArcGis return error for this
> large one.
>
> I am running R 2.7.1 under windows/xp. Is there a way of do this job using
> R ou RSaga? (unfortunately I don´t have GRASS installed), and my
> experience with RSAGA is near zero. My computer is 4GB ram.  I can load the
> images on ArcGis and Erdas without problem, but I only don´t know how do
> this task.
>

Try and use GRASS. It is made for these types of operations. Since R is 
memory-bound (for most practical purposes) a sequential-access approach like 
GRASS should work much better. There is a windows installer for GRASS, or you 
can just install the latest QGIS: this comes with GRASS!

Cheers,

Dylan


-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341