FuzzyNear
Summary
Defines a fuzzy membership function around a specific value which is defined by a midpoint (which is assigned a membership of 1), with a defined spread decreasing to zero.
Discussion
The tool that uses the FuzzyNear object: Fuzzy Membership.
The equation for this function is:
The inputs to the equation are \(f1\), the spread, and \(f2\), the midpoint. Increasing the spread causes the fuzzy membership curve to become steeper.
This function is useful if the membership is near a specific value.
The input values can be either integer or floating-point positive values.
This function is similar to the FuzzyGaussian fuzzy membership function except the FuzzyNear function has a more narrow spread.
Syntax
FuzzyNear(midpoint, spread)
| Name | Explanation | Data type |
|---|---|---|
|
midpoint |
The value with a fuzzy membership of 1. The default is the midpoint of the range of values of the input raster. |
Double |
|
spread |
Defines the spread of the function. The spread generally ranges from 0.001 to 1 with the larger the value results in a steeper distribution from the midpoint. The default value is 0.1. |
Double |
Properties
| Name | Explanation | Data type |
|---|---|---|
|
midpoint (Read and Write) |
The value that defines the midpoint for the membership function. |
Double |
|
spread (Read and Write) |
Defines the spread of the membership function. The larger the value results in a steeper distribution from the midpoint. |
Double |
Code sample
Demonstrates how to create a FuzzyNear class and use it in the FuzzyMembership tool within the Python window.
import arcpy
from arcpy.sa import *
from arcpy import env
env.workspace = "c:/sapyexamples/data"
outFzyMember = FuzzyMembership("as_std", FuzzyGaussian(9, 0.1))
outFzyMember.save("c:/sapyexamples/fzynear")
Performs a FuzzyMembership using the FuzzyNear class.
# Name: FuzzyNear_Ex_02.py
# Description: Scales input raster data into values ranging from zero to one
# indicating the strength of a membership in a set.
# 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
inRaster = "as_std"
# Create the FuzzyNear algorithm object
midpoint = 11
spread = 0.2
myFuzzyAlgorithm = FuzzyNear(midpoint, spread)
# Run FuzzyMembership
outFuzzyMember = FuzzyMembership(inRaster, myFuzzyAlgorithm)
# Save the output
outFuzzyMember.save("c:/sapyexamples/fzynear2")