Changes between Version 47 and Version 48 of WKTRaster/GDALDriverSpecificationWorking
- Timestamp:
- 07/27/12 08:09:02 (12 years ago)
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WKTRaster/GDALDriverSpecificationWorking
v47 v48 142 142 === Topic: Some general thoughts === 143 143 144 '''Open Question (Pierre, july 2012)''': In the worst case, a VRT is basically the same thing as a PostGIS raster table (just a bunch of non aligned rasters) and I was wondering if we could not simply copy the code of the VRT driver and adjust it so it reads all the rasters of a PostGIS query instead of reading them from the file system. Basically the VRT file resume to all the rasters returned by a where query whatever their alignment are. If I'm right then we would benefit from any smart optimization implemented by Frank in the VRT driver... 145 144 146 * The driver should not be dependent on a "rid" column nor request for it. Currently, the 'rid' attribute is hardcoded in some queries. A better approach would be looking for a primary/unique key. This is useful when getting subdatasets (each subdataset should be identified by its primary key). But just when write ability exists. In case of reading, you could always create a GDAL-internal key for each tile loaded assuming there is a "management" structure for the set of tiles. Pierre says that, if there’s no primary key, you could use a query with “where ST_UpperLeftX(rast) = XXX AND ST_UpperLeftY(rast) = YYY". 145 147 146 '''Open Question''': Why does the key should only be required when the write ability exists?148 '''Open Question''': Why does the key should only be required when the write ability exists? 147 149 148 150 * The driver should not be dependent on the "raster_column" view since entries in this view, contain useful information ONLY if AddRasterConstraint was called on the table. It can however be dependent on "raster_overview" since no overview exists if it is not visible in raster overview.