Hi, I responded to a recent post on the derby-user list on this topic. I am working on a project to add spatial functionality to Derby through user created tables and procedures. I am interested in taking the next step and looking at incorporating spatial functionality in Derby.
The biggest issue I see is one of licensing. The concept of 'spatial datatypes' might seem simple enough, but there is no real point without spatial functions to go with them. The Open Geospatial Consortium (OGC) http://www.opengeospatial.org published a standard set of these, and there are a handful of high grade open source implementations. There is a huge amount of work in these implementations, and they rely on very specialized expertise. In the Java world there is just one that has stood the test of time, the JTS Topology Suite http://sourceforge.net/projects/jts-topo-suite/ . However JTS is LGPL, and the prospect of re-engineering the functionality just to get an Apache 2.0 license is mind boggling. Even worse, two of the OGC spatial filters (Distance Within and Beyond) require Coordinate Reference System (CRS) transformation if the database features are stored in a geographic CRS. The obvious choice for that functionality is Geotools http://geotools.codehaus.org/ , again LGPL. The Apache web site indicates there are unresolved questions about the compatibility of Apache 2.0 and GPL. Does anyone have more information on the status of LGPL? One alternative is to take the route that MySQL went. Leave out all the secondary filtering and just support Minimum Bounding Rectangle (MBR) queries. However the same question keeps surfacing on the MySQL spatial list with monotonous regularity: when will MySQL get 'real' spatial functionality. Personally I think a user-space solution is preferable to a half-way solution like MySQL. Regards, Peter
