= — Returns
if A's bounding box is the same as B's. Uses double precision bounding box.
if the bounding box of raster A
is the same as the bounding box of raster B. PostgreSQL uses the =, <, and > operators defined for rasters to
perform internal orderings and comparison of rasters (ie. in a GROUP BY or ORDER BY clause).
This operand will NOT make use of any indexes that may be available on the rasters. Use ~= instead. This operator exists mostly so one can group by the raster column.