3D map data, specifically the kind you see on GPS units, or more recently on smart phones, almost always features a 'HUD' like view, which I'm trying to implement in an application of mine. I have OpenStreetMaps data (offline) available to my application, where all the geometry is specified in latitude and longitude.
With 2D maps, there's a 'standard', where almost everyone uses N*N tiles of Mercator projected data. But with 3D data,
I don't know what projection I should be using (I still have to map the latitude, longitude and altitude to x,y,z)
I'm not too sure what's the best way to make data continually available in 'chunks' to a display engine as a user pans and zooms the map view
If it matters, I'm using C++ with the OpenSceneGraph library (which is basically a scene graph wrapper/toolkit for OpenGL). I'd appreciate any advice!