LARGE-SCALE VECTOR DATA DISPLAYING FOR INTERACTIVE MANIPULATION IN 3D LANDSCAPE MAP

摘要

Displaying large-scale 3D vector data in landscape map is very important, as 3D vector data can provide many important information, such as: precise geographic boundaries, areas, 3D text marks, different attributes identity, precise path and many important invisible information in real world (e.g.: underground things) and etc. In this paper, we present a technique that is capable of efficiently and precisely displaying 2D vector data in 3D landscape map. In order to release CPU from heavy computation, texture-based approach is selected to render 2D vector data on 3D terrain blocks in browsing mode. Geometry-based approach is selected in interactive manipulation mode or precise expression of vector data is required. We use static terrain mesh (STM) instead of dynamic terrain mesh on the base of SOAR algorithm, to improve efficiency of 3D geometry primitives creation from 2D vector data in real-time, and to support interactive manipulation of 3D vector object. In addition, several scales of 2D vector data map are used to build a pyramid of vector data. These strategies made large-scale vector data displaying easy in 3D landscape map.