I want to show 15 mile radius circles around points in a map using gBuffer. As far as I can tell I have the points and the map in the same projection, but when I produce the circles on the map, they ...

How can I compile GDAL with GEOS support enabled? I managed to compile it in release only but I need a debug dll too. Is there a Tutorial somewhere?

I have two arrays of polygons called grid_1 and grid_2. grid_1 has 1,500,000 polygons and grid_2 has 60,000 polygons. As it is much too computationally expensive to calculate the intersecting polygon ...