Can you describe your elevation dataset? Is it USGS NED? At which resolution (10 meter, 3 meter?)?
As for table partitioning... http://www.postgresql.org/docs/9.0/static/ddl-partitioning.html You'll probably partition spatially, though an easy solution is to have a table for each input raster file. -bborie On Tue, Jul 23, 2013 at 11:05 AM, Jayson Gallardo <jaysontra...@gmail.com>wrote: > Thanks for responding. Could you outline how I would go about doing a > partitioned table structure? My only concern with tile size is processing > time. Most of my queries will involve areas of less than 1 mi^2, and I > would clip the data into that shape. I just don't know where to start! > There's not too many resources online/print dealing with postgis rasters in > detail. > > > On Tue, Jul 23, 2013 at 12:57 PM, Bborie Park <dustym...@gmail.com> wrote: > >> You may not need to drop all the constraints when adding additional data >> to the table. You most likely will need to drop is the maximum extent >> constraint. Assuming the input rasters have the same scale, skew and SRID >> as that found in the table, you don't need to drop those corresponding >> constraints. >> >> If you're going to do the continental US at a fine resolution (e.g. 1 >> meter), you do NOT want to put all the rasters in one table. You'll want to >> use a partitioned table structure and should consider a bigger tile size >> (depending on your hardware). >> >> -bborie >> >> >> On Tue, Jul 23, 2013 at 10:43 AM, Jayson Gallardo <jaysontra...@gmail.com >> > wrote: >> >>> I've looked and looked, but I have not been able to find an answer to my >>> question. I have downloaded elevation data for the state of Arkansas (in >>> the form of multiple tiles), and used raster2pgsql to upload it into a >>> single table: >>> >>> raster2pgsql -I -C -e -F -t 50x50 -l 2,4 n*/grdn* public.dem_elevation | >>> psql -U postgres -d testdb -h localhost -p 5432 >>> >>> I did this because I didn't know how to pull the data if they were in >>> separate tables. Now, however I would like to add elevation data for other >>> areas. I tried to just add it to the current table, but that required >>> dropping the constraints which for such a huge amount of data seems to take >>> a long time (I let it run for 24+ hours and it didn't finish). So, my >>> question is, if I load all my rasters as individual tables, how could I run >>> something similar to this query on them all (from a python script): >>> >>> SELECT ST_AsGDALRaster(ST_CLIP(ST_Union(rast), >>> ST_GeomFromText(WKT,900913)),'GTiff') FROM "dem_elevation" WHERE >>> ST_Intersects(rast, ST_Transform(ST_GeomFromText(WKT,900913),4269)) >>> >>> My goal, if it's not obvious, is to clip elevation data and export it to >>> a GTiff format and perform some operations on that raster data. Eventually, >>> I would like to put the whole continental US elevation data into my >>> database, so I need to be able to do so, while still being able to query >>> them based on an area of interest the user selects from a map. I started >>> working with PostGIS and Mapserver last month, so please forgive my >>> ignorance on such topics. Thanks in advance >>> >>> _______________________________________________ >>> postgis-users mailing list >>> postgis-users@lists.osgeo.org >>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >>> >>> >> >> _______________________________________________ >> postgis-users mailing list >> postgis-users@lists.osgeo.org >> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >> >> > > _______________________________________________ > postgis-users mailing list > postgis-users@lists.osgeo.org > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > >
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