NbrCircle (arcpy.sa)

Récapitulatif

Defines a circle neighborhood which is created by specifying the radius in either map units or number of cells.

Illustration

NbrCircle neighborhood example for the FocalStatistics function

NbrCircle neighborhood example for the BlockStatistics function

Discussion

Tools that use neighborhood circle object: Block Statistics, Focal Statistics, Point Statistics, and Point Density.

A circle neighborhood is created by specifying a radius value. The radius is identified in cell or map units, measured perpendicular to the x- or y-axis. When the radius is specified in map units, it is converted to a radius in cell units. The resulting radius in cell units produces an area that most closely represents the area calculated by using the original radius in map units. Any cell center encompassed by the circle will be included in the processing of the neighborhood.

Syntaxe

NbrCircle ({radius}, {units})

Paramètre	Explication	Type de données
radius	The radius of the circle neighborhood. (La valeur par défaut est 3)	Double
units	Defines the units of the neighborhood. CELL —The unit of measurement is in cells. MAP —The units are in map coordinates. (La valeur par défaut est CELL)	String

Propriétés

Propriété	Explication	Type de données
radius (Lecture/écriture)	The radius of the circle neighborhood.	Double
units (Lecture/écriture)	Defines the units of the neighborhood.	String

Exemple de code

NbrCircle example 1 (Python window)

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

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outNbrC = BlockStatistics("block", NbrCircle(2, "MAP"))
outNbrC.save("C:/sapyexamples/output/blstatsnbrc2")

NbrCircle example 2 (stand-alone script)

Implements the BlockStatistics tool using the NbrCircle class.

# Name: NbrCircle_Ex_02.py
# Description: Uses the NbrCircle object to execute BlockStatistics 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
inRaster = "block"

# Create the Neighborhood Object
radius = 2
myNbrCirc = NbrCircle(radius, "MAP")

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

# Execute BlockStatistics
outBlkStat =  BlockStatistics(inRaster, myNbrCirc, "MINIMUM", "DATA")

# Save the output 
outBlkStat.save("C:/sapyexamples/output/blstat_cir3")