"NULL or invalid blankCellValue"
*Cause: The blankCellValue element could not be found in the metadata of
a blank GeoRaster object, or the specified blankCellValue element
value was NULL or invalid.
*Action: Call SDO_GEOR.setBlankCellValue to add blankCellValue to the
metadata whenever the isBlank element value is TRUE, and make sure
that the specified blankCellValue element value is not NULL and is
in the range as designated by the cellDepth definition of the