[GRASS-user] v.rast.stats over a large vector file
razmjooeis at faunalia.co.uk
razmjooeis at faunalia.co.uk
Sat Nov 27 10:43:56 EST 2010
Hi Markus
I managed to compile grass6.5 and the plugin.
Now when I try to run it, it comes up with this error:
/usr/local/grass-6.5.svn/scripts/v.rast.stats2: 350: Syntax
error: "(" unexpected
Cheers
Sab
> 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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