WMS:Flood Extent Map

The Conversion | Flood->Extent Coverage command in the Flood menu allows you to create a polygon in a flood extent coverage that defines the inundated area as determined in the flood depth data set. The default inundation limit is 0.0, but you can specify any positive depth value as the inundation limit and WMS will generate a polygon that conforms to that limit.

To create the flood extent map you must specify the flood depth and water surface elevation data sets along with the inundation limit. You can optionally have WMS force or stamp in the flood extent coverage to the TIN. This will insure that you have TIN vertices with depth values at exactly 0.0. This is not the case in the original data sets computed by the flood plain delineation algorithm. The 0.0 (or any other depth contour value) value is likely interpolated along a triangle edge between two vertices. Stamping the flood extent coverage into the TIN is particularly useful for confining the display of water surface elevation values to be within the flood extent region. While the inundation limit for flood depth is a constant value (0.0), the value of water surface elevation at the inundation limit is not. By stamping in the flood extent coverage and updating the associated data sets water surface elevation contours can be controlled since WMS will set vertices outside of the flood extent coverage to be inactive and those inside to be active.

Related Topics

• Overview of Flood Plain Delineation
• Delineate Flood Plain
• Create Flood Depth Map
• Create Impact Map