The WCPS component translates a request into rasdaman's query language, rasql [10],and hands this to rasdaman for processing. The results obtained from rasdaman are MIME-encoded and shipped back to the client, together with the XML-encoded manifest
describing them.The rasdaman (“raster data manager”) raster server extends standard relational databases with multidimensional raster data of unlimited size [1], [3]. Its query language, rasql, extends standard SQL with a raster language. Rasql expressions are optimized on server side and executed against the database where the raster objects are stored partitioned in sets of blobs (binary large objects). The relational database, then, for a Terabyte-size raster objects holds a million blobs of about a Megabyte size each – a value which has proven suitable for high request throughput. Rasdaman on principle can plug into virtually any database system and is commercially operational on top of Oracle, Informix, DB2, and PostgreSQL. For the purpose of the WCPS development the open-source system PostGreSQL is used which has proven competitive indeed against its commercial counterparts.