GVU Technical Report Number:
GIT-GVU-99-20
Title:
Efficient Ray Intersection for Visualization and Navigation of Global
Terrain using Spheroidal Height-Augmented Quadtrees
Authors:
Zachary Wartell
William Ribarsky
Larry F. Hodges
Abstract:
We 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 complexities and present solutions.
The final algorithm is suited for interactive terrain selection, collision
detection and simple LOS (line-of-site) queries on global terrain.
Keywords:
Quadtree, global terrain, spheroid, geodetic coordinates
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