Here is what I need to do:
1) Have a webpage with a zoomable map. We currently use google maps api, but willing to try others.
2) I have around 1000 lat/lon points. For each point, I would like to create a (transparent) yellow circle with 1 mile radius.
3) In the areas where two or more circles overlap, I would like the color to be changed to green. I do not want different shades of green or yellow, just simply green or yellow (no blending).
From my searching it seems the only way to accomplish this is to generate the overlay offline using any language I can, and then just tile it and overlay it over google maps. Wondering if there is anything out there that can do this fairly easily "online". Any example of doing something sililar would be greatly appreciated!