A tutorial for DB2 working with GeoTools is now available. This extends the excellent GeoTools QuickStart tutorial to illustrate how to exploit the spatial capabilities provided by the IBM DB2 databases on Windows, *IX, mainframe (z/OS) and cloud (BlueMix dashDB) platforms.
There are also related tutorials for using DB2 with the GeoServer and uDig projects based on GeoTools as well as the GDAL/OGR and QGIS GIS projects.
