I am looking for a spatial index library in C# that has to be able to index geometries (circles, polygons, polylines) as well as answer intersection questions. I found NetTopologySuite (NTS) and some other one-file solution project but I wonder if I missed anything significant?
NTS is pretty good but somewhat heavy. The second one is a one man art and apparently I have to pick it up and maintain myself. I wonder if I can find something that is supported and tested.
I am looking for C# one but if I can get hands on Java one, I can adapt that.
libspatialindex seems to have all the features you want, but it's in C++
JSI is a Java project, but it only works with rectangles.