Ticket #1609 (closed enhancement: wontfix)
[raster] Implement ST_Merge for ST_Union
|Reported by:||pracine||Owned by:||pracine|
ST_Merge(raster1, band1, raster2, band2, nodataval, pixeltype)
Merge two rasters together by unioning their extent and burning the last raster without taking the other raster pixel values into account. Works on multiple bands. The nodata value, when specified, replace the existing nodata values. SRIDs must be the same for the two rasters.
The goal of this function is to be used by ST_union when unioning rasters with the 'LAST' option.
It could be first easily implemented as a wrapper around ST_MapAlgebra. Ideally it should be a C function that we could actually use to optimize the two rasters ST_MapAlgebra in certain situations (when extentype is INTERSECTION and the expression is 'RAST2' and there is no alternative expressions).