Exact and approximate computations of watersheds on triangulated terrains

Mark de Berg, Constantinos Tsirogiannis
2011 Proceedings of the 19th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems - GIS '11  
The natural way of modeling water flow on a triangulated terrain is to make the fundamental assumption that water follows the direction of steepest descent (dsd). However, computing watersheds and other flow-related structures according to the dsd model in an exact manner is difficult: the dsd model implies that water does not necessarily follow terrain edges, which makes designing exact algorithms difficult and causes robustness problems when implementing them. As a result, existing software
more » ... existing software implementations for computing watersheds are inexact: they either assume a simplified flow model or they perform computations using inexact arithmetic, which leads to inexact and sometimes inconsistent results. We perform a detailed study of various issues concerning the exact or approximate computation of watersheds according to the dsd model. Our main contributions are the following.
doi:10.1145/2093973.2093985 dblp:conf/gis/BergT11 fatcat:zsr5ynpzkjeo5ojiyztf337ujq