Fuzzy Overlay (Spatial Analyst)

Summary

Combine fuzzy membership rasters data together, based on selected overlay type.

Learn more about how Fuzzy Overlay works

Usage

Syntax

FuzzyOverlay (in_rasters, {overlay_type}, {gamma})
ParameterExplanationData Type
in_rasters
[in_raster,...]

A list of input membership rasters to be combined in the overlay.

Raster Layer
overlay_type
(Optional)

Specifies the method used to combine two or more membership data.

  • ANDThe minimum of the fuzzy memberships from the input fuzzy rasters.
  • ORThe maximum of the fuzzy memberships from the input rasters.
  • PRODUCT A decreasive function. Use this when the combination of multiple evidence is less important or smaller than any of the inputs alone.
  • SUMAn increasive function. Use this when the combination of multiple evidence is more important or larger than any of the inputs alone.
  • GAMMA The algebraic product of the Fuzzy Sum and Fuzzy Product, both raised to the power of gamma.
String
gamma
(Optional)

The gamma value to be used. This is only when the Overlay type is set to GAMMA.

Default value is 0.9.

Double

Return Value

NameExplanationData Type
out_raster

The output raster which is the results of applying the fuzzy operator.

This output will always have a value between 0 and 1.

Raster

Code Sample

FuzzyOverlay example 1 (Python window)

This example combines the input membership rasters with the AND overlay type to identify the minium membership value between them.

import arcpy
from arcpy.sa import *
from arcpy import env
env.workspace = "c:/sapyexamples/data"
outFzyOverlay = FuzzyOverlay(["fzymembout1", "fzymembout2"], "AND")
outFzyOverlay.save("c:/sapexamples/output/fuzzover.tif")
FuzzyOverlay example 2 (stand-alone script)

This example combines the input membership rasters with a GAMMA overlay type.

# Name: FuzzyOverlay_Ex_02.py
# Description: Combine fuzzy membership rasters data together based on 
#    selected overlay type ("GAMMA" in this case). 
# 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
inRasterList = ["fzymembout1", "fzymembout2"]

# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")

# Execute FuzzyMembership
outFzyOverlay = FuzzyOverlay(inRasterList, "GAMMA", 0.9)

# Save the output
outFzyOverlay.save("c:/sapexamples/output/fuzzoverlay")

Environments

Related Topics

Licensing Information

ArcView: Requires Spatial Analyst
ArcEditor: Requires Spatial Analyst
ArcInfo: Requires Spatial Analyst

6/29/2011