ETG_FlowDirectionDinf

Flow Direction D-infinity

Generates a Flow Direction raster in which each cells represents the direction of flow for this cell in the DEM using the D-infinity method.

Inputs:

Input DEM raster dataset
Output raster name and format

Outputs:

A Floating raster representing the Flow Direction according to the D-infinity (Deterministic Infinity) method.

Example:

An example of Flow Direction D-infinity output.

Notes:

The D-infinity method was suggested by Tarboton (1997). In it Flow Direction is defined as the angle of the steepest descent determined by analysis of 8 triangular facets formed by the 3x3 cell neighborhood.
The flow direction values are in Decimal Degrees from 0 to 360.0. The value of 0.0 indicates an outlet and all other values represent the direction of flow starting from North in clockwise direction.
For example a value of 90 indicates flow to the East and a value of 225 - flow to South West.
The D-infinity method allows flow divergence - the flow from a cell will either go to one or two of the neighboring cells.This is a better representation of water flow on divergent slopes.
See Hydrological functions for more information on the hydrological functionality.
The input format accepted are file based rasters - ERDAS IMAGINE or Tagged Image File Format (TIFF).
The .NET ToolBox for ArcGIS Desktop accepts also FileGDB Raster inputs.
For file based rasters initially the name of the output raster define the raster format:
- .img extension (for example raster1.img) - ERDAS IMAGINE image.
- .tif extension (for example raster1.tif - image.
- The initial output raster format can be changed by selecting the desired output in the dialog.

Running Programmatically

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Parameters

Expression	Explanation
Function Name	FlowDirectionDinf
<input raster>	A String representing the input DEM raster dataset.
<output raster>	A String - the full name of the output raster.

Running the function

ETSPath used in the table below is the full path to ETSRun.exe (E.G. "C:\Program Files\ETSpatial Techniques\ETSurface\ETSRun.exe")

UnitsDegrees

Language	Syntax
Python	subprocess.call([ETSPath, "FlowDirectionDinf", "input raster", "output raster"])
.NET using ETSRun.exe	StartInfo.FileName = ETSPath StartInfo.Arguments = "FlowDirectionDinf" "input raster" "output raster"
.NET using ETSOutX.dll	FlowDirectionDinf(input raster, output raster)
ArcPy	arcpy.FlowDirectionDinf("input raster", "output raster")

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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Reference:

Tarboton, D. G., (1997),"A New Method for the Determination of Flow Directions and Contributing Areas in Grid Digital Elevation Models", Water Resources Research, 33(2): 309-319