[GRASS-user] Speeding Up Reprojection of Large Raster Maps

[Daniel Victoria]

I thinkg you have to use "poors man parallelization"... That is, split
the work and issue multiple commands separately.

So I'd try splitting the large raster into small chunks and then
projecting each one separately, sending the project command to the
background. The problem is that, if the grass command changes the
region settings, things might not work. So maybe, your best bet would
be to run the projection in small chunks of the raster file but
outside of grass, using gdalwarp

Take a look at the parallel grass jobs wiki.
http://grass.osgeo.org/wiki/Parallel_GRASS_jobs

Cheers
daniel

On Sat, Mar 10, 2012 at 2:25 PM, Rich Shepard <rshepard at appl-ecosys.com> wrote:
>  I've a couple of very large DEMs; approximately 40G cells each. I am
> reprojecting them to the project's location, but they take ~10 hours to
> complete. One's running on my desktop (dual-core AMD II X2 CPU with 4G RAM),
> the other's running on my Dell Latitude E5410 (quad-core Intel i7 with 8G
> RAM). Grass-6.5svn is compiled with openmp on both machines.
>
>  Is there any way to make use of the multiple cores and (comparatively)
> large amounts of memory to speed up the reprojection process? I know that
> I'll have the same issue with other projects so, while I can certainly
> continue to run other applications and processes while these slowly grind
> away, I'd like to learn if I can shorten the required times.
>
> Rich
>
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