[GRASS-user] Re: improve v.rast.stats speed?

G. Allegri giohappy at gmail.com
Thu Feb 19 07:14:34 EST 2009

I forgot an important question: does anyone have had better
experiences with it? Maybe it's only a problem with my computer or my
grass build...

2009/2/19 G. Allegri <giohappy at gmail.com>:
> Hello list.
> Yesterday I needed to use v.rast.stats on a 1793 areas covering a
> 4415x6632 raster (with resolution 50m/pixel). I've used it without
> extended statistics but the processing time was, with an euphemism,
> very very long. After 5 hours it wasn't finished yet. As I needed it
> for today morning I've decided to reproduce it with ArcGIS: 40
> seconds. I've tried to investigate what was going wrong, the
> bottleneck, but at the end I suppose that it's a problem of the script
> itself (the looping chain of r.mapcalc and r.univar, the creation and
> deletion of the MASK in each loop).
> Is there any way to improve the performance of v.rast.stats? Should we
> rewrite it in C and avoid the use of MASKs?
> I must say that this has been a shock for my collegues seeing this
> impressive performance differences... And I would like to contribute
> in healing them! :)
> Giovanni

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