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
