239 | | '''ST_AsPolygon(raster) -> polygon geometry set''' - Returns a set of geometry, one for each group of pixel having the same value. |
240 | | |
241 | | This is a set-returning function (SRF). The shape of each polygon should exactly follow pixels edges. |
242 | | |
243 | | A ST_AsPolygon(raster, 'GROUP') variant should regroup every resulting polygon having the same value into complex (or multipart) polygons. |
| 239 | '''ST_AsPolygon(raster) -> geomval set''' - Returns a set of "geomval" value, one for each group of pixel having the same value. |
| 240 | |
| 241 | This is a set-returning function (SRF). A "geomval" value is a complex type composed of a polygon geometry (one for each group of contiguous pixel of sharing same value) and the value associated with these pixels. The value associated with the group of pixel are always returned as a double precision value. The shape of each polygon follow pixels edges. |
| 242 | |
| 243 | A ST_AsPolygon(raster, 'REGROUP') variant should regroup every resulting polygon having the same value into complex (or multipart) polygons. |