Changes between Version 62 and Version 63 of WKTRaster/SpecificationWorking01
- Timestamp:
- Dec 16, 2009, 11:15:21 AM (15 years ago)
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WKTRaster/SpecificationWorking01
v62 v63 192 192 '''ST_Box2D(raster) -> BOX2D''' - Returns a BOX2D representing the maximum extents of the geometry. 193 193 194 The only difference with ST_Envelope(raster) is that ST_Box2D(raster) returns a BOX2D, not a geometry. 195 194 196 This function replaces ST_Raster_to_box2d() and should be used for the "raster AS box2d" cast. It should also be used instead of ST_raster_envelope when creating indexes in gdal2wktraster.py (to be tested). 195 197 … … 198 200 If the raser is rotated, the envelope is a non-rotated box enclosing the rotated raster. 199 201 202 The only difference with ST_Box2D(raster) is that ST_Envelope(raster) returns a geometry, not a BOX2D. 203 200 204 This function should replace the actual ST_raster_envelope() function which is wrongly named. 201 205 202 206 '''ST_ConvexHull(raster) -> polygon geometry''' - Returns the minimum convex geometry that encloses every significant pixel from the raster. 203 207 204 By default the resulting polygon TAKES the NODATA values into account. The resulting polygon enclose only pixels having a significant value (different than the NODATA value). The ST_ConvexHull(raster, 'WITHNODATA') variant DO 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). 208 By default the resulting polygon TAKES the NODATA values into account. The resulting polygon enclose only pixels having a significant value (different than the NODATA value). 209 210 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). 205 211 206 212 '''ST_Shape(raster) -> polygon geometry''' - Returns a geometry encomparsing every pixel having a significant value (different than the NODATA value). 207 213 208 This polygon geometry might contain holes if some internal areas of the raster contain pixels with NODATA values. 214 This polygon geometry might contain holes if some internal areas of the raster contain pixels with NODATA values. By opposition ST_ConvexHull(raster) never contains holes. 209 215 210 216 '''ST_AsPolygon(raster) -> polygon geometry set''' - Returns a set of geometry, one for each group of pixel having the same value. … … 216 222 This function should be used with precaution on raster with float pixel type as it could return one polygon per pixel. This kind of raster should be reclassified (using the planned ST_Reclassify(raster,...) function) before using ST_AsPolygon(). 217 223 224 This function is at the base of the first version of ST_Intersection which compute the intersection between a raster and a geometry. 225 218 226 '''ST_AsSmoothPolygon(raster) -> polygon geometry set''' - Returns a set of geometry, one for each group of pixel having the same value. 219 227 … … 226 234 227 235 228 '''ST_Intersects(raster|geometry, raster|geometry)'''[[BR]][[BR]] 229 '''ST_Intersection(raster|geometry, raster|geometry, ‘raster’|’geometry’)->raster/geometry'''[[BR]] 236 '''ST_Intersects(raster|geometry, raster|geometry)''' 237 238 '''ST_Intersection(raster|geometry, raster|geometry, ‘raster’|’geometry’)->raster/geometry''' 230 239 231 240 ----