You can append one image to another image when the two images have the same number of bands.

Image appending is useful when the geospatial images are collected at intervals and the captured image later needs to be appended to the existing image to make a large image of the whole spatial area. Image appending is also useful for updating the existing image with a new image.

The SDO_GEOR_AGGR.append procedure implements image appending by partially updating the existing GeoRaster object with another GeoRaster object. If the existing GeoRaster object contains pyramids, the pyramids with blocking are partially updated with the new data.

Example 6-17 appends one image to another, with pyramids with blocking are updated at the same time. Because the appendParam parameter specifies 'nodata=true', the NODATA values in the overlapping area are considered transparent.

DECLARE
    gr1 sdo_georaster;
    gr1 sdo_georaster;
BEGIN
     select georaster into gr1 from georaster_table where georid = 1 for update;
     select georaster into gr2 from georaster_table where georid = 2;
     sdo_geor_aggr.append(gr1, gr2, 0, 'nodata=true');
     update georaster_table set georaster = gr1 where georid= 1;
     commit;
END;
/