Just to be clear from the start, I’ve never used Google maps in any of my programs/projects, so I have a little knowledge on this matter. Also, I found some other posts in SO about Google maps, but I’m not sure if any of these really helps in my situation.
What I want to do is add another map above the already existing Google map. The new overlay map would have some degree of transparency in order for the original Google map to be visible too. Something like this: http://crf.casa.ucl.ac.uk/screenRoute.aspx?s=386&d=105&w=False
How can I do this? What technologies should I look into? I’m a Java developer, but any answer in any language would be really helpful.
It depends on how detailed/large the overlay needs to be. MapTiler is fantastic if you need to be able to zoom in to a very detailed overlay, but if your overlays don’t need to be quite so huge, I’d recommend using a GGroundOverlay(GroundOverlay in V3). It would be pretty easy to change dynamically. Here is Google’s demo.
As far as MapTiler goes – if you have a set of overlays you want to change dynamically, you can generate the tiles for all of the overlays, and then easily switch between them. But if you’re creating the overlays dynamically, you’ll probably need to implement a tile server. Check out Mapnik and TileCache.