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RadiusFixed

Summary

Defines a fixed search radius by specifying a distance and a minimum number of points required for analysis. If the required number of points is not found within the specified distance, the search radius will be increased until the specified minimum number of points is found.

Discussion

Tools that use radius objects: Kriging and IDW.

Syntax

RadiusFixed({distance}, {minNumberOfPoints})

Name Explanation Data type

distance

(Optional)

The distance specifies the distance as a radius within which input sample points will be used to perform the interpolation. The value of the radius is expressed in map units. The default radius is five times the cell size of the output raster.

Double

minNumberOfPoints

(Optional)

The minNumberOfPoints is an integer defining the minimum number of points to be used to perform the interpolation.

If the required number of points is not found within the specified distance, the search distance will be increased until the specified minimum number of points is found.

When the search radius needs to be increased, it is done so until the minNumberOfPoints fall within that radius, or the extent of the radius crosses the lower (southern) and/or upper (northern) extent of the output raster. NoData is assigned to all locations that do not satisfy the above condition.

The default value is 0.

Long

Properties

Name Explanation Data type

distance

(Read and Write)

The distance, in map units, specifying that all input sample points within the specified radius will be used to perform interpolation.

Double

minNumberOfPoints

(Read and Write)

The minNumberOfPoints is an integer defining the minimum number of points to be used for interpolation. If the required number of points is not found within the specified distance, the search distance will be increased until the specified minimum number of points is found.

Long

Code sample

RadiusFixed example 1 (Python window)

Demonstrates how to create a RadiusFixed class and use it in the Kriging tool within the Python window.

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
myRadius = RadiusFixed(80000)
outKriging = Kriging("ca_ozone_pts.shp", "ELEVATION", "SPHERICAL", "", myRadius)
outKriging.save("C:/sapyexamples/output/krigradfix")
RadiusFixed example 2 (stand-alone script)

Calculates a surface with the IDW interpolation tool using the RadiusFixed class.

# Name: RadiusFixed_Ex_02.py
# Description: Uses the RadiusFixed object to run IDW tool
# 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
inFeature = "ca_ozone_pts.shp"

# Create the Radius Object
distance = 15000
minNumPoints = 3
searchRadius = RadiusFixed(distance, minNumPoints)

# Run IDW
outRadFix = Idw(inFeature, "elevation", 2000, 2, searchRadius)

# Save the output
outRadFix.save("C:/sapyexamples/output/idwradfix")