I use the USGS NED 10 meter for California with one table for each input raster. In the partitioned table scheme, data tables inherit from a template (parent) table. Queries run on the parent table access the inherited tables.
-bborie On Tue, Jul 23, 2013 at 11:56 AM, Jayson Gallardo <[email protected]>wrote: > Yes, it's usgs ned. And I initially went with one table for each input > tile, but I didn't know how to join (or union) them together for my query. > On Jul 23, 2013 1:14 PM, "Bborie Park" <[email protected]> wrote: > >> 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 <[email protected] >> > 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 <[email protected]>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 < >>>> [email protected]> 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 >>>>> [email protected] >>>>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> postgis-users mailing list >>>> [email protected] >>>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >>>> >>>> >>> >>> _______________________________________________ >>> postgis-users mailing list >>> [email protected] >>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >>> >>> >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >> >> > _______________________________________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > >
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