Extending service area polygons to fill flow boundary layer

Applies To
Product(s): WaterGEMS, WaterCAD
Version(s): V8i, CONNECT Edition
Area: Modeling
Original Author: Jesse Dringoli, Bentley Technical Support Group


The total consumption allocated to nodes from Loadbuilder (such as with the Proportional Distribution by Area method) is less than the total flow in the flow boundary polygon, due to the service areas not extending to fill all flow boundary polygons. What Can I do?


In a case where the flow boundary polygon extends beyond the outermost edges of the model, you can consider using the "Polygon Boundary layer" option in the Thiessen Polygon tool. This is an alternative option to the "buffering percentage", which will extend the service area polygons of each node to fill the flow boundary polygon. So, you could create a shapefile with one single polygon spanning the bounds of your "flow boundary" layer and use that to generate the Thiessen polygon.

Note: If you notice small inaccuracies where the polygons meet (such as a small space or small overlap) when zoomed far in, this may be due to the model being located at coordinated with a very large number (such as 2,000,000 ft, 7,000,000 ft). Our developers will look into improvements to the Thiessen Polygon calculations with large coordinates for a future release (reference # 471982)

Thiessen Polygon generated with 10% Buffer Percentage:

Thiessen Polygon generated with 70% Buffer Percentage:

Thiessen Polygon generated with Flow Boundary polygon: