Cause: The two GeoRaster objects whose layers are to be combined together either had different row or column dimension sizes, or their georeferencing information did not match. See the solution below.
Error solution: Make sure the objects have the same row and column dimension sizes. If neither is georeferenced, their ULTCoordinate values must be the same. Otherwise, they must be both georeferenced and cover the same area in the model space.
Database version: Oracle 11g Release 2 (11.2)