Efficient management of terrain elevation and feature data for 3D-guidance display

This paper presents an efficient approach for rendering terrain elevation and feature data applicable to cockpit displays presenting guidance information in a 3-dimensional format. A primary goal is to achieve a real-time capability with a high update rate (25-30 images per sec) using a low-cost PC based computer. Basically, the data management approach consists of a hierarchical adaptive triangulation technique for dealing with the terrain elevation data in the memory. The interpolation hierarchical surplus is used as a criterion to detect redundant data and serves to control the error of the terrain approximation. A high frame rate can be reached with this level-of-detail mechanism, including an easy visibility check due to the hierarchical adaptive strategy. Furthermore, a special organization of the data is developed in order to reduce the required memory and to manage a large database. For this purpose, parts of the data can be exchanged during runtime with the use of a particular data format on harddisc. On multiprocessor computer architectures, the reloading data process can be performed in the background without interrupting the rendering by starting parallel running tasks (threads) while on single processor architectures a scheduler is sharing CPU time among the graphic and reloading processes.