networkCatchmentArea

Delineate Catchments

Delineates the Catchment areas based on a Single Direction Network (SDN). Based on the input SDN network (for example rivers) the function finds the Sinks (Outlets), trverses the SDN upstream and outputs polygons representing the catchment areas for each sink (outlet).

Inputs:

A Network created with ET GeoWizards (.etn file). Must be a Single Direction Network (SDN)
Input Point Barrier layer. The points of this layer represent barriers. The closest edge to each of these points will be considered closed and will not participate in the network analysis.

Outputs:

A Polygon feature layer representing the catchment areas

The attribute table of the output will have a field ET_Zone that identifies the catchment.

A Point feature layer with points that represent the sinks in the network. The values of the ET_Zone field in the output polygon layer will be populated with the IDs of the points in the sink layer.

Example:

Input rivers together with the output Sinks (Outlets) and delineated catchment areas.

Input rivers together with the output Sinks (Outlets) and delineated catchment areas

Running Programmatically

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Parameters

Expression	Explanation
Function Name	SDNDelineateCatchment
<Network to Use>	A String - the full name of the Network file (.etn).
<output catchment dataset>	A String - the full name of the output catchments polygon layer.
<output sinks dataset>	A String - the full name of the output sinks/outlets point layer.
{Input Barrier Points}	A String representing the input layer with barrier points. Must be of Point type.

Running the function

ETGWPath used in the table below is the full path to ETGWRun.exe (E.G. "C:\Program Files\ETSpatial Techniques\ETGeo Wizards\ETGWRun.exe")

Language	Syntax
Python	subprocess.call([ETGWPath, "SDNDelineateCatchment", "Network to Use", "output catchment dataset","output sinks dataset", "Input Barrier Points"])
.NET using ETGWRun.exe	StartInfo.FileName = ETGWPath StartInfo.Arguments = "SDNDelineateCatchment" "Network to Use" "output catchment dataset" "output sinks dataset" "Input Barrier Points"
.NET using ETGWOutX.dll	SDNDelineateCatchment(Network to Use, output catchment dataset, output sinks dataset,Input Barrier Points)
ArcPy	arcpy.SDNDelineateCatchment(Network to Use, output catchment dataset, output sinks dataset, Input Barrier Points)

Notes:

<> - required parameter
{} - optional parameter
See examples for Python , .NET or ArcPy
The argument separator for StartInfo.Arguments is space. If a string might contain a space, you need to double quote it.

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