My only concern with this approach is with how well it will handle a large number of points. I have asked for some type of upper bound, and the answer I got was 'a-lot', most likely going to be in the thousands.
So I am thinking I may try to create a WMS style web service - where a bounding box, image height & width are the request parameters, the server queries the points and does the rendering, and the resultant image sent back to client.
Does anyone know any such open source apis/sdks that contain this functionality? I know such tools exist in qgis and arcgis desktop - but i am looking to do this in a service.