Quantitative Analysis of Culling Techniques for Real-time Rendering of Digital Elevation Models

Michael Hesse
University of Calgary
Department of Computer Science
Calgary, AB, Canada T2N1N4

Marina Gavrilova

University of Calgary
Department of Computer Science
Calgary, AB, Canada T2N1N4

e-mail: marina@cpsc.ucalgary.ca

http://www.cpsc.ucalgary.ca/~marina

Keywords
ROAM, culling techniques, error metrics, terrain data, GIS rendering.

Abstract

The paper is concerned with investigation of effects of culling techniques on quality and smoothness of terrain data visualization within a 3D interactive environment. We utilize the Real-Time Optimally Adapting Mesh (ROAM) approach, extended with a number of efficient techniques such as implicit coordinates method within the patch array representing ROAM and the viewpoint dependent triangle rendering method for dynamic level of detail (LOD) updates. The method, which allows dynamic and interactive first person view, is combined with the View Frustum culling, the Backface culling and an innovative Relational Position Culling technique based on a pre-process point of view approach for realistic terrain representation and real-time level of detail reduction. Standard error metrics are used to verify the rendering consistency. The experimentation is conducted on two data sets representing simple gradual contour changes (Susanville, California) and complex steep contour changes (Kluane National Park, USA). Based on the extensive experimentation, the set of heuristics identifying applicability of each of the culling techniques to a specific terrain data set is derived.