3.4 Creating New GeoRaster Objects

Before you can store a GeoRaster image in a GeoRaster table, you must create the GeoRaster object and insert it into a GeoRaster table before you start working on it. To create a new GeoRaster object, you have the following options:

• Initialize an empty GeoRaster object, using the SDO_GEOR.init function.

• Create a blank GeoRaster object, using the SDO_GEOR.createBlank function.

You cannot perform any GeoRaster operations if the object has not been properly created (that is, if the object is an atomic null). The SDO_GEOR.init and SDO_GEOR.createBlank functions initialize GeoRaster objects with their raster data table and raster ID values if these are not already specified, and the GeoRaster DML trigger ensures that the raster data table name and raster ID value pair is unique for the current user.

If the new GeoRaster object will hold raster cell data (resulting from another GeoRaster procedure, such as SDO_GEOR.subset or SDO_GEOR.copy), and if the raster data table for this new GeoRaster object does not exist, you must first create the raster data table. For information about creating a raster data table, including examples, see Creating Raster Data Tables.

To avoid potential GeoRaster data problems (some of which are described in Maintaining GeoRaster Objects and System Data in the Database), an initialized GeoRaster object must be registered in the GeoRaster system views, which is done automatically when you insert the GeoRaster object into a GeoRaster table. This should be done before you perform any other operations on the GeoRaster object. Any GeoRaster operations that need to manipulate the raster data table raise an exception if the source or target GeoRaster object is not registered.