ETG_StrahlerStreamOrder

Strahler Stream Order

Assigns an order to each stream segment according to the system proposed by Strahler (1952). The order of the stream section starting at the stream head is assigned to 1. The order increases by 1 only when two sections of the same order intersect. For example if two sections of order 1 intersect, the following section will be assigned an order of 2. When two sections of different order intersect, the following section preserves the higher order.

Inputs:

A Stream raster dataset.
A D8 Flow Direction raster dataset
Output raster name and format

Outputs:

A Strahler Stream Order raster with cell values indicating the assigned order for each stream section.

Example:

An example of Strahler Stream Order result.

Notes:

The input Stream raster should be represented as values greater than or equal to one on a background of NoData
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 InputFlowDirectionRaster define the raster format:
- .img extension (for example raster1.img) - ERDAS IMAGINE image.
- .tif extension (for example raster1.tif - image.
- The initial InputFlowDirectionRaster format can be changed by selecting the desired output in the dialog.

Running Programmatically

(Go to TOP)

Parameters

Expression	Explanation
Function Name	StrahlerStreamOrder
<InputStreamRaster>	A String representing the input Stream raster dataset.
<InputFlowDirectionRaster>	A String representing the input Flow Direction raster dataset.
<OutputRaster>	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, "StrahlerStreamOrder", "InputStreamRaster", "InputFlowDirectionRaster", "OutputRaster"])
.NET using ETSRun.exe	StartInfo.FileName = ETSPath StartInfo.Arguments = "StrahlerStreamOrder" "InputStreamRaster" "InputFlowDirectionRaster" "OutputRaster"
.NET using ETSOutX.dll	StrahlerStreamOrder(InputStreamRaster, InputFlowDirectionRaster, OutputRaster)
ArcPy	arcpy.StrahlerStreamOrder("InputStreamRaster", "InputFlowDirectionRaster", "OutputRaster")

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.

(Go to TOP)