[postgis-users] raster extent and performance problem... anyone?

[Bborie Park]

What version of GDAL are you using?  Could you try GDAL trunk?  I don't
trust anything other than trunk (1.9.x or below) due to various bugs.
At some point, I'll dig into the PostGIS raster driver...

-bborie

On 08/23/2012 07:01 AM, William Kyngesburye wrote:
> almost forgot: PostGIS 2.0.1, on PG 9.1.4.  PPC OS X.
> 
> On Aug 23, 2012, at 8:46 AM, William Kyngesburye wrote:
> 
>> I created a raster table for a large area of DEM data, with index and constraints, no overviews.  When I run gdalinfo on the table, it takes about 15m to query to get the extents, which are then wrong.
>>
>> Original 32bit float geotiffs = 27GiB (uncompressed), 84W, 36N to 71W, 45.5N (not complete coverage)
>>
>> In PostGIS = 25GiB, 74W, 33.5N to 61W, 43N
>>
>> There are 15936 records in the table, which matches the number of input TIFFs and the tile size I used (actually 22 more than the input), so it looks like all the data was imported.
>>
>> It looks like the data was shifted 10 deg east and 2.5 deg south.
>>
>> When I try to extract a region from that with gdal_translate, it takes the 15m to check the extants again, then extracts garbage.
>>
>> I'm just getting started with PG rasters and don't know enough about the SQL needed to check within PG if everything is OK there or not (extents, extract some data to tif) or if it's a GDAL problem.
>>
>> A GDAL vrt of the geotiffs processes quickly and reports the correct extents.
>>
>> -----
>> William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
>> http://www.kyngchaos.com/
>>
>> "Time is an illusion - lunchtime doubly so."
>>
>> - Ford Prefect
>>
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> 
> -----
> William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
> http://www.kyngchaos.com/
> 
> "I ache, therefore I am.  Or in my case - I am, therefore I ache."
> 
> - Marvin
> 
> 
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-- 
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkpark at ucdavis.edu