[basex-talk] Add a spatial index ?

Hello I'am a phd student and i explore actually multiples no-sql solutions to store and process location data such as gml or gpx. I have already familiar with BaseX, and the combinaison XML/XQuery providing the flexibility needed for my project. However, process spatial data need spatial index such as R-tree in order to be processed efficiently. I would like to know if an implementation of spatial index into BaseX exist or are in project ? And if not, does the BaseX architecture allow to add new index easily ? Best regard Haderer Nicolas