Creating an Outlet Theme

WMS requires three primary data layers in order to build a hydrologic modeling schematic (sometimes referred to as a "tree") from GIS data. These three data layers include a basin boundary layer, a stream network layer, and an outlet or basin confluence layer.

In order to be able to create a hydrologic model from these three GIS vector data layers, topologic relationships between stream reaches, basin boundaries, and outlet points must be explicitly defined. An outlet data layer (point shape file) is created representing these intersection points using the Create Outlet Coverage… command in the WMSHydro menu. This command brings up the dialog shown in Figure 1 and is used to select the desired options for creating an outlet layer.

A new outlet theme will be created and so a name should be provided for this theme. The vertices could be inserted at the common intersection points by turning on the corresponding check box. If vertices are not inserted at the basin boundary-stream intersection points, WMS will not recognize the intersection points as outlet points when the WMS-Hydro super file is read into WMS.

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