Changes between Version 7 and Version 8 of WKTRasterTutorial01

Timestamp:

06/10/10 13:48:01 (15 years ago)

Author:

pracine

Comment:

—

WKTRasterTutorial01

@@ -303 +303 @@
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-One approach to make this operation without PostGIS WKT Raster would have been to first convert our 13 rasters to 13 shapefiles, import them in PostGIS and do a traditionnal intersection query between geometries only. The problem is that converting only one of those SRTM file is very difficult... The vector version of only one of those files exceed the limit of 2 GB imposed on shapefiles and the GML equivalent file is more than 10 GB... The WKT Raster approach goes like this: "since it is mostly impossible to convert those raster to vector, load them all into PostGIS as is and only the smallest part of them raster will be vectorized to do the requested operation", this using the very efficient GiST index, the versatility of GDAL and of power of the postGIS vector engine. XXXXXWe will later examine alternative solutions to this particular vectorization problem as well as how we could do the complete raster/vector operation using other software.
+One approach to make this operation without PostGIS WKT Raster would have been to first convert our 13 rasters to 13 shapefiles, import them in PostGIS and do a traditionnal intersection query between geometries only. The problem is that converting only one of those SRTM file is very difficult... The vector version of only one of those files exceed the limit of 2 GB imposed on shapefiles and the GML equivalent file is more than 10 GB... The WKT Raster approach goes like this: "since it is mostly impossible to convert those raster to vector, load them all into PostGIS as is and only the smallest part of them raster will be vectorized to do the requested operation", this using the very efficient GiST index, the versatility of GDAL and of power of the postGIS vector engine.