[postgis-users] Why so terribly slow?

[Bborie Park]

On 02/10/2012 09:13 AM, DavidRA wrote:
> Several test later, I'm sure that ST_MapAlgebraExpr() suits me perfectly.
> Besides it's very easy to use.
>
> It's slower than using the equivalent function on a GIS tool like GRASS but
> I think that could be expected, isn't it? Though I'm curious about the
> reasons...
>
> Thanks again for this and for the tips on the weighted average.
>

MapAlgebra is currently slow because it has yet to be optimized as the 
current code is the first attempt.  It is hoped to improve the 
performance over time but unlike GIS desktop systems, there are more 
factors in play with PostGIS raster (mainly PostgreSQL, which can be 
nebulous at times).

-bborie

-- 
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkpark at ucdavis.edu