[GRASS-user] v.rast.stats over a large vector file

[Daniel Victoria]

I used StarSpan to do something similar (but with less vector feature:
6000). It worked pretty well. Maybee worth a try?

http://starspan.projects.atlas.ca.gov/doku/doku.php

Daniel

On Fri, Nov 26, 2010 at 10:41 AM, Markus Metz
<markus.metz.giswork at googlemail.com> wrote:
> On Fri, Nov 26, 2010 at 12:32 PM,  <razmjooeis at faunalia.co.uk> wrote:
>> Dear list
>>
>> I am trying to run v.rast.stats for a large vector file. It contains
>> around 700000 buildings representing buildings.
>>
>> here is my g.region info
>> g.region -p
>> projection: 99 (Transverse Mercator)
>> zone:       0
>> datum:      osgb36
>> ellipsoid:  airy
>> north:      183010.45829976
>> south:      153516.19024768
>> west:       513122.49174945
>> east:       555953.95182415
>> nsres:      4.99987592
>> ewres:      5.00017045
>> rows:       5899
>> cols:       8566
>> cells:      50530834
>>
>> THe problem I am having is the process is extremely slow. It has done 150
>> features out of 700000 areas after 2 hours.
>> I need just the average raster value within each building (feature).
>> My questions are:
>> - Is there something I can do to speed up the process?
>> - Is there a way just to get the average value rather than the whole set
>> of statistical parameters (I am not even using -e option)
>>
> You could try v.rast.stats2 from grass-addons, it should complete in
> less than 1 hour. When using v.rast.stats2 and grass 6.4, you also
> need r,univar.zonal from grass-addons (not needed for grass 6.5).
>
> Markus M
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