Hello, On Tue, Jun 29, 2010 at 6:46 PM, <[email protected]> wrote: > Hi, superb job. Congratulations. > > I am a geotools/geoserver developer and one of my jobs is fetching image > tiles or the corresponding pyramid tiles from jdbc data sources. Some weeks > ago, I added support for Oracle Georaster and I want to support WKT > Georaster too. > > wktraster makes it quite simple to achieve this. Is there any database > layout you recommend. (A table for the image and one for each pyramid, or > put all the tiles into one table having an attribute "level",.....). >
I'd recommend one table for each separate tiled image. That's, in fact, one of the ways WKT Raster works, in terms of raster table arrangement. > I have seen "gdal2wktraster.py", is this the recommended way to import tiles > into postgis ? Yes, this is the way you should use now to import images into PostGIS. And related with pyramids, if you provide "-l <OVERVIEW_LEVEL>" as command line option, you will get overview tables named as o_<LEVEL>_<RASTER_TABLE> and will be populated with GDAL-provided overviews. Only regular blocking arrangements (see "-k" command line option too). If you use this "-l" command line option, you'll have to specify "-V" option too, only the first time you call the script. This option enables the creation of the needed RASTER_OVERVIEWS table. Oh, and the gdal2wktraster script generates a SQL output. You'll have to load into your raster-ready schema. > What is the table layout created/needed by this utility ? > You'll simply need to "raster-enable" your PostGIS schema by executing rt_pg/rtpostgis.sql, after compiling and installing WKT Raster. One additional table, named "RASTER_COLUMNS", will be created in your schema. As I said above, if you use "-V" option the first time you execute the loader script (gdal2wktraster), another new table, named "RASTER_OVERVIEWS" will be created in your schema too. This is all you need to start :-) Comments are welcome, as Pierre said. > Cheers > Christian > > > > Quoting Pierre Racine <[email protected]>: > >> Hi everybody, >> >> I'm pleased to announce that you can now do intersections between rasters >> and geometries very much like you used to do geometry/geometry >> intersections in PostGIS. For this, PostGIS WKT Raster introduces two new >> functions to PostGIS: ST_Intersects(geometry, raster, band) and >> ST_Intersection(geometry, raster, band). >> >> As its geometry/geometry sister, ST_Intersects(geometry, raster, band) >> returns TRUE if the withvalue area of a raster or a raster tile (nodata >> value are ignored) intersects a geometry and ST_Intersection(geometry, >> raster, band) returns the geometry/value set of geometries representing the >> intersection between the geometry and each polygonized group of pixel >> sharing a same value from the raster and its associated value. Example: >> >> SELECT polyid, >> (ST_Intersection(the_geom, rast)).geom, >> (ST_Intersection(the_geom, rast)).val >> FROM my_polygons, srtm_tiled >> WHERE ST_Intersects(rast, the_geom) >> >> or, a bit more complex, but much faster and returning the same result: >> >> SELECT polyid, (gv).geom, (gv).val >> FROM (SELECT polyid, ST_Intersection(the_geom, rast, 1) AS gv >> FROM my_polygons, srtm_tiled >> WHERE ST_Intersects(rast, the_geom)) foo >> >> These functions works with any kind of geometry so you can intersect any >> road, river, polygons or point layer with your favorite elevation or land >> cover raster of any resolution and any size. You can also load any number >> of raster in the database with one command line to constitute a unique >> table raster coverage of any shape (no matter if your group of raster do >> not form a rectangular coverage). >> >> You will find a complete tutorial on how to use those two new functions >> here: http://trac.osgeo.org/postgis/wiki/WKTRasterTutorial01. A reference >> is available here: >> http://postgis.refractions.net/documentation/manual-svn/RT_reference.html >> and chapter 13 of "PostGIS in Action" is also a very good introduction to >> WKT Raster. >> >> Compilation and installation info are available in the project home page: >> http://trac.osgeo.org/postgis/wiki/WKTRaster >> >> These features are the result of two years of collaboration between many >> people and companies interested in bringing raster into PostGIS. I would >> like to thanks particularly Steve Cumming who initially made all this >> possible, Sandro Santilli who wrote the base code, Mateusz Loskot who wrote >> the Python loader, Jorge Arevalo who wrote the GDAL driver and >> ST_DumpAsPolygons(), Regina and Leo Obe who are doing so many things and >> believed in the project from the beginning by adding a chapter about WKT >> Raster in "PostGIS in Action" and also David Zwarg who wrote most of the >> setter functions. >> >> This is the first step toward a first complete raster/vector analysis and >> manipulation SQL API. We hope to make of PostGIS with WKT Raster the most >> powerful and complete GIS analysis and manipulation high level language >> ever (!!!). WKT Raster should normally be totally integrated into PostGIS >> in PostGIS release 2.0. Upcoming functions should include ST_Reclass, >> ST_Clip, ST_AsRaster, ST_Resample. >> >> Let us know your need and your experience with WKT Raster. >> >> Thanks, >> >> Pierre Racine >> >> _______________________________________________ >> gdal-dev mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > > > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program. > > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Jorge Arévalo DEIMOS Space Internet & Mobilty Division Ronda de Poniente 19. Edificio Fiteni VI, portal 2, 2º 28760 Tres Cantos (Madrid) Tel: +34 91 806 34 50 - ext: 155 [email protected] http://gis4free.wordpress.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
