[postgis-users] Dted elevations

[Gold, Jack L (US SSA)]

Spatial index is in place.  A rebuild of the database seems to have solved the problem, but I still don't know what caused sudden slow-down.  If I had a corrupted raster table, would that cause this type of response?  Thanks for the help.  Turns out I had a similar problem at least a year ago and Bborie helped out, but I reviewed those adjustments and everything seems to be in place.  I'm looking at a combination of level 0, level 1 and level 2 dteds all loaded in the same raster table as well.  I'm wondering if that is generating some havoc on the lookup.

--Jack

-----Original Message-----
From: postgis-users-bounces at lists.osgeo.org [mailto:postgis-users-bounces at lists.osgeo.org] On Behalf Of Pierre Racine
Sent: Friday, May 09, 2014 1:26 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] Dted elevations

What happened when you remove "and st_value (dted_elevations.rast, f.geom) is not null"? You get null values?

Do you have many nodata values in your raster?

How is your raster tiled? Did you build a spatial index on the raster tiles?

Pierre

> -----Original Message-----
> From: postgis-users-bounces at lists.osgeo.org [mailto:postgis-users- 
> bounces at lists.osgeo.org] On Behalf Of Gold, Jack L (US SSA)
> Sent: Friday, May 09, 2014 1:01 PM
> To: 'postgis-users at lists.osgeo.org'
> Subject: [postgis-users] Dted elevations
> 
> I know this question has already been answered a hundred times but I 
> am at a remote location currently with only email access right now and 
> I hope someone can help.  The following query is taking close to a 
> second to run and I think it should be much faster.
> 
> Select st_value from (with f as ( select st_transform ( st_SetSRID( 
> st_MakePoint('106','32'), 4326) as geom) select 
> st_value(dted_elevations.rast, f.geom) from dted_elevations cross join 
> f where st_intersects ( dted_elevations.rast , f.from) and st_value 
> (dted_elevations.rast, f.geom) is not null) as st_value;
> 
> Any help is greatly appreciated.
> 
> Jack Gold
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