I recently came across Spatial4J. I wanted to let Rya folks know about it, and see if anyone has experience with it, especial in regard to using it as alternative to JTS/GeoTools libraries and relationship to GeoMesa.
It is a spatial / geospatial library with an Apache license that is used by the Apache Lucene project. It seems to have a lot of what I need for doing filter functions in SPARQL. Also of special interest to Ryians (Ryamancers? Ryaphiles?) is that Spatial4J is used by the latest version of RDF4J (AKA OpenRDF/Seseme). Rya heavily depends on RDF4J, but is not yet up to the version that features Spatial4J. Because it is ASL licensed, it might make a good alternative to our dependencies on JTS libraries. However, there is an "optional" dependency for JTS for polygons. I'm wondering if that means that it won't handle polygons unless the JTS libraries (LGPL) are included. Perhaps it just a convenience for people that are already using the JTS geometry classes. This probably become clear once I get more into the API. david.
