Focal Flow (Spatial Analyst)
Summary
Determines the flow of the values in the input raster within each cell's immediate neighborhood.
Illustration
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OutRas = FocalFlow(InRas1) |
Usage
Focal Flow evaluates the eight immediate neighbors of a cell to determine the flow.
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The resulting values from the tool measure flow into, not out of, a cell.
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The output values are derived from the binary representation of the results of the analysis.
Syntax
| Parameter | Explanation | Data Type |
in_surface_raster |
The input surface raster for which to calculate the focal flow. The eight immediate neighbors of each cell are evaluated to determine the flow. The input raster can be integer or floating point. | Raster Layer |
threshold_value (Optional) |
Defines a value that constitutes the threshold, which must be equaled or exceeded before flow can occur. The threshold value can be either an integer or floating-point value. If the difference between the value at a neighboring cell location and the value of the processing cell is less than or equal to the threshold value, the output will be 0 (or no flow). | Double |
Return Value
| Name | Explanation | Data Type |
| out_raster |
The output focal flow raster. The output raster is always of integer type. | Raster |
Code Sample
This example determines the binary representation of flow for the input raster with a threshold value of 10.
import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
focalFlowOut = FocalFlow("elevation", 10)
focalFlowOut.save("C:/sapyexamples/output/flowout")
This example determines the binary representation of flow for the input raster with a threshold value of 5.
# Name: FocalFlow_Ex_02.py
# Description: Determines the flow of the values in the
# input raster within each cell's immediate neighborhood.
# Requirements: Spatial Analyst Extension
# Author: ESRI
# Import system modules
import arcpy
from arcpy import env
from arcpy.sa import *
# Set environment settings
env.workspace = "C:/sapyexamples/data"
# Set local variables
inRaster = "elevation"
threshold = 5
# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")
# Execute FocalFlow
outFocalFlow = FocalFlow(inRaster, threshold)
# Save the output
outFocalFlow.save("C:/sapyexamples/output/focalflow")