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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!

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1 Answer

up vote 1 down vote accepted

It depends on what kind of navigation you're talking about. I'll assume car navigation.

Since you're only showing a small slice of Earth (as opposed to Google Earth, which can show the whole Earth), you can simplify some things, for example:

Good luck!

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protected by whuber Jul 26 '12 at 16:35

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