WMS:Edge Swapping

TINs are generated in WMS using the Delauney criteria. This method creates a set of triangles which are as equiangular as possible, and while this generally creates a good terrain surface, it does not ensure that all important hydrologic features such as streams and ridges will be honored with triangle edges. A classic problem which occurs and inhibits drainage analysis is the "false dam". A false dam occurs during the triangulation process when an edge straddles a natural channel, forming a dam in the bottom of the channel as shown in Figure a. False dams are easily corrected by swapping the triangle edge ab to cd as illustrated in Figure b. Triangle edges are swapped using the Swap Edge tool and clicking on the edge which needs to be swapped.

Related Topics

• Breaklines
• Creating Vertices
• Triangulating
• TIN Option