O'Reilly Network: GPS, Palm Pilot, OpenGL ... Let's Go!Dec 11, 2000, 19:18 (0 Talkback[s])
(Other stories by Chris Halsall)
[ Thanks to Chris Halsall for this link. ]
"When you start to think about data returned by a GPS receiver, you immediately realize that it's three dimensional. Thus, the display of GPS data will often be very well suited for implementation in OpenGL, letting the standard do most of the heavy lifting. It's not being lazy, it's being efficient!"
"GPS fixes include three values: longitude, latitude, and altitude. For simple cases covering relatively small areas (a few hundred kilometers), these can be mapped to X, Y, and Z and displayed. However, for more advanced cases where high precision is required, the lat, long, and altitude must be mapped onto a spheroid as defined by the map datum."
"In order to keep our demonstration program as simple as possible, we're going to take the easy route and do the simple linear transform. This will be adequate for our purposes, but those who require greater precision are encouraged to investigate the WGS83 specification."