Efficient Flow Computation on Massive Grid Terrain Datasets

Abstract

As detailed terrain data becomes available, GIS terrain applications target larger geographic areas at ner resolutions. Processing the massive data involved in such applications presents signi cant challenges to GIS systems and demands algorithms that are optimized both for data movement and computation. In this paper we develop e cient algorithms for flow routing on massive terrains, extending our previous work on flow accumulation. We have implemented these algorithms in the Terraflow system, which is the rst comprehensive terrain flow software system designed and optimized for massive data. We compare the performance of Terraflow with that of state of the art commercial and open-source GIS systems. On large terrains, Terraflow outperforms existing systems by a factor of 2 to 1000, and is capable of solving problems no system was previously able to solve.