investigation about complex vector graphics for points related data

Using advanced styling we can show more information for each point using multiple svg source objects, scaling and rotating each of them.

In this case are visualized the "exx", "eyy" and "x_azimuth" of geodetic strain rate where red color indicates contraction and blue color indicates extension.

Open issues:
 - a wide range of items dimensions
 - zoom management (geonode 2.0 probably helps us with a working wms_scale_denominator variable)
 - better edges rendering
 - speed optimization (using precalculated columns maybe)