| Derives the catchment areas of
the input features (Sources) using their spatial location and the weight of
each source. The function allocates the cells of the output raster to the
sources based on minimum cost to reach a source from the cell. The cost is
calculated as distance from the cell to the source multiplied by the weight
of the source. The smaller the weight value of a source is, the greater the
influence of the source is.
This function produces results similar to the
results from the Weighted Voronoi Diagram
function. The algorithm is different and non-integer weights can be
used. Since the Weighted Voronoi Diagram is much faster, the better option
is to use it instead of this function unless you need to have double values
for the weights.
The performance of the function depends very
much on the difference between the smallest and largest weights. The larger
this difference is, the slower the function will be.
Inputs:
- A point feature class(Sources).
- 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. Any numeric field
(integer or double) can be used as a weight field.
- Cutoff cost - cells with larger than
this cost (distance x weight) to reach will not be allocated to any
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.
Examples:
 |
Points labeled with their weights.
Integer weights used - the results very similar to the results
produced by
Weighted Voronoi Diagram
. In this case the use of
Weighted Voronoi Diagram
function is recommended. |
 |
Points labeled with their weights.
Double values for the
weights used. The difference between the smallest weights (indicated
on the image) and the largest ones close to 100 times.
Expect long processing time. |
Notes:
- Initially the name of the output raster
defines the raster format
- no extension specified - ESRI binary GRID
- .img extension (for example raster1.img) -
ERDAS IMAGINE image.
- .tif extension (for example raster1.tif -
Tagged Image File Format (TIFF) image.
- The initial output raster format can be
changed by selecting the desired output in the dialog.
- Currently only file based rasters are
supported. Rasters cannot be stored in a GeoDatabase. After you get the
desired result, you can export the raster to a GeoDatabase using the
standard ArcGIS tools.
- The input feature class must be in a projected
coordinate system.
- The result raster can be easily converted to
a polygon feature class using the standard ArcGIS Raster To Polygon tool
- The attributes can be transferred to the
polygons by joining the Raster Attribute Table to the polygons using
GRID_CODE field of the feature class and the Value field of the raster
attribute table.
ToolBox
implementation
Command line syntax
ETS_GPCostAllocationSource <Input
Points> <Out Raster> < ID Field> <Weight Field> < Cell Size> {Cut
Off Cost}
Parameters
| Expression |
Explanation |
| <Input
Points> |
A
Point layer feature class |
| <Out
Raster> |
A String
- the full name of the output raster (A raster with the same full
name should not exist). The output raster type depends on the extension
of the output file(see Notes above) |
| <
ID Field> |
A String representing the name
of the field in the input point feature class to be used as point ID. |
|
<Weight Field> |
A String representing the name
of the field in the input point feature class that are going to be used as
weights. |
| <Cell Size> |
A Double representing the cell
size of the output raster. |
|
{Cut Off Cost} |
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 |
Scripting syntax
ETS_GPCostAllocationSource (Input
Points,
Out Raster, ID Field, Weight Field, Cell Size, Cut Off Cost)
See the explanations above:
<> - required parameter
{} - optional parameter
All ESRI
products mentioned are trademarks of Environmental Systems Research
Institute, Inc.
Copyright: Ianko Tchoukanski |