[postgis-users] Raster pixel value

[Bborie Park]

On Sun, Dec 4, 2011 at 11:09 AM, Tom van Tilburg
<tom.van.tilburg at gmail.com> wrote:
> Pierre,
>
> I just ran a test to see the difference between my old method and your new
> method with ST_Clip and ST_SummaryStatsAgg and came up with the following:
>
> 1. The old way took 38 secs. whereas the new one 46 (100 polygons, usually
> covering part of 1 raster tile).
> 2. ST_Clip appears to fill up nodatavalues with zero as soon as they fall
> within the polygon. I have been staring a while at your code but couldn't
> really see what caused this. I thought it might be a wrong MinPossibleVal
> but it doesn't seem to be.
>
>

I'd say use whatever is faster.  Unfortunately, Pierre (who wrote
ST_Clip) is on holiday until sometime in January so he won't be around
and I haven't had the time to see what ST_Clip is doing.

-bborie

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