VfBinary

Disponible avec une licence Spatial Analyst.

Synthèse

Defines the relationship between the vertical cost factor and the vertical relative moving angle through a binary function. If the vertical relative moving angle is greater than the low-cut angle and less than the high-cut angle, the vertical factor is set to the value associated with the zero factor; otherwise it is infinity.

Illustration

Graph of the binary vertical factor.

Discussion

This object is used in the Distance Accumulation and Distance Allocation Spatial Analyst tools, as well as the Path Distance, Path Distance Allocation, and Path Distance Back Link Legacy Distance tools.

The vertical factor (VF) object defines the relationship between the vertical cost factor and the vertical relative moving angle (VRMA).

VF defines the vertical difficulty encountered in moving from one cell to the next.

VRMA identifies the slope angle between the FROM or processing cell and the TO cell.

When the VRMA is larger than the low-cut angle and smaller than the high-cut angle, the VF for moving between the two cells is set to the value associated with the zeroFactor. If the VRMA is greater than the highCutAngle or lower than the lowCutAngle, the VF is set to infinity.

Syntaxe

VfBinary ({zeroFactor}, {lowCutAngle}, {highCutAngle})

Paramètre	Explication	Type de données
zeroFactor	The zeroFactor will be used to position the y-intercept of the binary function. (La valeur par défaut est 1.0)	Double
lowCutAngle	The VRMA degree defining the lower threshold, below which (less than) the VFs are set to infinity. (La valeur par défaut est -30.0)	Double
highCutAngle	The VRMA degree defining the upper threshold, beyond which (larger than) the VFs are set to infinity. (La valeur par défaut est 30.0)	Double

Propriétés

Propriété	Explication	Type de données
zeroFactor (Lecture et écriture)	The zeroFactor is used to position the y-intercept for the vertical factor class.	Double
lowCutAngle (Lecture et écriture)	The VRMA degree defining the lower threshold, below which (less than) the VFs are set to infinity.	Double
highCutAngle (Lecture et écriture)	The VRMA degree defining the upper threshold, beyond which (larger than) the VFs are set to infinity.	Double

Exemple de code

VfBinary example 1 (Python window)

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

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
myVerticalFactor = VfBinary(1.0, -30, 30)
outDistAccum = DistanceAccumulation("Source.shp", "", "elev.tif",
                                   "cost.tif", "elev.tif",
                                    myVerticalFactor)
outDistAccum.save("C:/sapyexamples/output/distAccumVfB.tif")

VfBinary example 2 (stand-alone script)

Performs a DistanceAccumulation analysis using the VfBinary class.

# Name: VfBinary_Ex_02.py
# Description: Uses the VfBinary object to run the 
#              DistanceAccumulation 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
inSourceData = "source.shp"
inCostRaster = "costraster.tif"
inElevation = "elev.tif"

# Create the VfBinary Object
zeroFactor = 1.0
lowCutAngle = -30
highCutAngle = 30
myVerticalFactor = VfBinary(zeroFactor, lowCutAngle, highCutAngle)

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

# Run DistanceAccumulation
outDistAccum = DistanceAccumulation(inSourceData, "", inElevation,
                                    inCostRaster, inElevation,
                                    myVerticalFactor)

# Save the output 
outDistAccum.save("C:/sapyexamples/output/distaccumvfB2.tif")