Wartell, ZacharyRibarsky, WilliamHodges, LarryGröller, E., Löffelmann, H., Ribarsky, W.2015-11-162015-11-161999978-3-7091-6803-5EG: 1727-5296Springer: 0946-2767https://doi.org/10.2312/vissym19991005We present an algorithm for efficiently computing ray intersections with multi-resolution global terrain partitioned by spheroidal height-augmented quadtrees. While previous methods support terrain defined on a Cartesian coordinate system, our methods support terrain defined on a two-parameter ellipsoidal coordinate system. This curvilinear system is necessary for an accurate model of global terrain. Supporting multi-resolution terrain and quadtrees on this curvilinear coordinate system raises a surprising number of complications.We describe the complex- ities and present solutions. The final algorithm is suited for interactive terrain selection, collision detection and simple LOS (line-of-site) queries on global terrain.10.2312/vissym19991005