Changes between Version 26 and Version 27 of WKTRaster/SpecificationWorking02
- Timestamp:
- 09/03/10 14:26:58 (14 years ago)
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WKTRaster/SpecificationWorking02
v26 v27 75 75 '''Variants''' 76 76 77 1) ST_Clip(raster, ulx , uly, lrx, lry) -> raster77 1) ST_Clip(raster, ulx float8, uly float8, width int, height int) -> raster 78 78 79 79 2) ST_Clip(raster, geometry) -> raster … … 83 83 84 84 85 Variant 1 ) takes the upper left and lower left corner of the desired zone. Variant 2) determine the extent of this zone from the extent of a geometry. Variant 3)determine the extent of this zone from the extent of a geometry and set all pixel outside the geometry to no data values.85 Variant 1 takes the upper left corner, the width and the height of the desired zone. Variant 2 determine the extent of this zone from the extent of a geometry. Variant 3 determine the extent of this zone from the extent of a geometry and set all pixel outside the geometry to no data values. 86 86 87 87 If the geometry is totally included into one pixel (a point for example), only this pixel is kept in the returned raster. … … 92 92 93 93 newrast := ST_AddBand(ST_MakeEmptyRaster(x2 - x1, y2 - y1, ST_Raster2WorldCoordX(rast, x1, y2), ST_Raster2WorldCoordY(rast, x1, y2), ST_PixelSizeX(rast), ST_PixelSizeY(rast),ST_SkewX(rast),ST_SkewY(rast), ST_SRID(rast)), ‘1BB’, 1, 0) 94 newrast := ST_MultiBandMapAlgebra(rast, newrast, ‘r 1’, ‘INTERSECTION’)94 newrast := ST_MultiBandMapAlgebra(rast, newrast, ‘rast1’, ‘INTERSECTION’) 95 95 96 96 Could also be implemented as ST_Intersection -> ST_Band(ST_Intersection(geometry, raster, band, “TRIM”), 1) Would require some kind of TRIM and would be slower.