High Throughput Maps

I need a script that will let me plot latitude/longitude points on a world or region map. I'm designing a site where a website manager can install a world or region map on their website and see a set of dots that describe the locations of their users. I need the site to manage potentially thousands of these maps at the same time, and allow for frequent updates. An update would be either adding a new dot to the map or clearing all the dots from the map. The maps need to be in either gif or jpeg output at the end of the day. The input would be a latitude/longitude pair (or list if you think it would be better) and the output would be the map of all latitude/longitude pairs for that particular map. I've thought of using GMT ([login to view URL]) to generate the maps, but the output format is postscript. While I can convert postscript to gif, I'm wondering if there is a better way that does not require redrawing all the map points every time in memory: namely just changing the pixel color in question on a gif image. Something that can be run fast so that server resources are less used. This code should be written in some language that will run as a command line script under linux, or through PHP as a function. I am only asking for the code which produces the image of the map, not any of the account or website management components. If you bid on this project, please additionally provide a short description of how you plan to approach the problem. This will be the most critical element in how I choose the coder for this project. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Linux, Apache, PHP.