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

[Markus Metz]

Markus Neteler wrote:
> On Thu, Feb 19, 2009 at 2:20 PM, G. Allegri <giohappy at gmail.com> wrote:
>   
>> Thanks for the ideas.
>> I've just tried Starspan but it's performance is still too slow. I've
>> let it run for 15 minutes...
>>     
>
> Can you please try GRASS 7?
> grass70/scripts/v.rast.stats/v.rast.stats.py
>   
grass70/scripts/v.rast.stats/v.rast.stats.py also uses r.mapcalc in 
every pass:

for i in cats:
    ...
    grass.mapcalc("MASK = if(...)

if v.rast.stats is faster in grass7, then probably because of improved 
raster libs. A speed increase from >5 hours to 40 seconds is unlikely 
since grass.mapcalc is still called 1793 times (assuming each area has a 
unique category) for a region with 4415x6632 cells...