Fuzzy Overlay (Spatial Analyst)
Combine fuzzy membership rasters data together, based on selected overlay type.
This tool is recommended for the use with the result of fuzzy membership tool. It is meant to be applied to rasters with values that range between 0 and 1.
The following lists the appropriate Overlay type to use for certain conditions.
- Use OR when any of the input evidence rasters can have a high value in order for the output to be a high value.
- Use AND when all of the input evidence rasters must have a high value in order for the output to be a high value.
- Use PRODUCT when the combined evidence is less important than any single evidence.
- Use SUM when the combined evidence is more important than any single evidence.
The GAMMA Overlay type is typically used to combine fuzzy combinations of more basic data. When Gamma is 1 the result is the same as Fuzzy Sum. When Gamma is 0 the result is the same as Fuzzy Product. Values in between allow the user to combine evidence between these two extremes and possibly different than Fuzzy And or Fuzzy Or.
A list of input membership rasters to be combined in the overlay.
Specifies the method used to combine two or more membership data.
The gamma value to be used. This is only when the Overlay type is set to GAMMA.
Default value is 0.9.
The output raster which is the results of applying the fuzzy operator.
This output will always have a value between 0 and 1.
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")
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 # 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")