Changes between Version 64 and Version 65 of WKTRaster/SpecificationWorking01
- Timestamp:
- Dec 16, 2009, 11:36:29 AM (15 years ago)
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WKTRaster/SpecificationWorking01
v64 v65 211 211 212 212 A ST_ConvexHull(raster, 'WITHNODATA') variant SHOULD NOT TAKE the NODATA value into account. It generally returns a square or rectangle polygon that can be rotated or not depending on the rotation of the raster. If the raster is not rotated ST_ConvexHull(geometry, 'WITHNODATA') is (almost) equivalent to ST_Envelope(raster). 213 214 '''Implementation details''' 215 216 The first variant ST_ConvexHull(raster) could be roughly implemented with a SQL or PL/pgSQL function looking like 'SELECT ' 213 217 214 218 '''ST_Shape(raster) -> polygon geometry''' - Returns a geometry encomparsing every pixel having a significant value (different than the NODATA value).