ETG_WeightedVoronoiAllocation

Weighted Voronoi Diagram

Derives the catchment areas of the input features (Sources) using their spatial location and the weight of each source. The smaller the weight value of a source is, the greater the influence of the source is.

Algorithm

All sources start growing at the same time. A source with weight = 1 increases its area every cycle, a source with weight = 2 every second cycle, a source with weight = 10 every tenth cycle and so on. The process finishes when all cells of the output raster are occupied. If cutoff distance is specified a source will stop increasing its area when it reaches the maximum radius of influence.

Inputs:

Input point feature dataset
Output raster name and format
The cell size of the output raster.
Source ID field. The values from this field will be allocated to the cells of the output raster.
Weight field. The values of this field will be used to define the weight of the sources. Only integer fields can be used for weight of the sources
Cutoff distance - a cell farther than this distance of a source cannot be allocated to this source - the maximum radius of influence of a source.

Outputs:

An integer raster. Each cell will have as a value the ID of the closest input point (Source). The extent of the output is equal to the extent of the input feature class.

Example:

Points labeled with their weights. No cutoff distance specified

Points labeled with their weights. Cutoff distance specified

Notes:

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	WeightedVoronoiAllocation
<InputFeatures>	A String - the full path to the input feature dataset.
<output raster>	A String - the full name of the output raster.
<CellSize>	A Double representing the cell size of the output raster.
<IDField>	A String representing the name of the field in the input point feature class to be used as point ID.
<WeightField>	A String representing the name of the field in the input point feature class that are going to be used as weights.
<CutOff>	A Double representing the cut off cost - the value of the cells with larger than this cost (distance x weight) to reach will be set to NODATA.

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")

CellSize

Language	Syntax
Python	subprocess.call([ETSPath, "WeightedVoronoiAllocation", "InputFeatures", "output raster", "CellSize", "IDField", "WeightField", "CutOff"])
.NET using ETSRun.exe	StartInfo.FileName = ETSPath StartInfo.Arguments = "WeightedVoronoiAllocation" "InputFeatures" "output raster" "CellSize" "IDField" "WeightField" "CutOff"
.NET using ETSOutX.dll	WeightedVoronoiAllocation(InputFeatures, output raster, CellSize, IDField, WeightField, CutOff)
ArcPy	arcpy.WeightedVoronoiAllocation("InputFeatures", "output raster", "CellSize", "IDField", "WeightField", "CutOff")

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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