Hi, I have worked wih GIS and geomtric algorithms since a long time ago. As far as I understand, you have a set of polygons, and a set of points??? That's the part I don't understand. Then you want to count/add some of those points? the ones inside polygnos? I still don't completelly understand what you need, but I thik I can do it. Depending on the requirementes I could use GDAL with C#, but at this point I feel that I really need more information about the problem