VfCos

Mit der Spatial Analyst-Lizenz verfügbar.

Zusammenfassung

Defines the relationship between the vertical cost factor and the vertical relative moving angle through a cosine function.

Abbildung

Graph of the cosine vertical factor.

Diskussion

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.

The VF is determined by the cosine function of the VRMA.

Syntax

VfCos ({lowCutAngle}, highCutAngle, {cosPower})

Parameter	Erläuterung	Datentyp
lowCutAngle	The VRMA degree defining the lower threshold, below which (less than) the VFs are set to infinity. (Der Standardwert ist -90.0)	Double
highCutAngle	The VRMA degree defining the upper threshold, beyond which (larger than) the VFs are set to infinity. (Der Standardwert ist 90.0)	Double
cosPower	The power to which the values in the cosine VRMA function will be raised. The VF is determined by: VF = cos(VRMA)power (Der Standardwert ist 1.0)	Double

Eigenschaften

Eigenschaft	Erläuterung	Datentyp
lowCutAngle (Lesen und schreiben)	The VRMA degree defining the lower threshold, below which (less than) the VFs are set to infinity.	Double
highCutAngle (Lesen und schreiben)	The VRMA degree defining the upper threshold, beyond which (larger than) the VFs are set to infinity.	Double
cosPower (Lesen und schreiben)	The power to which the values in the cosine VRMA function will be raised. The VF is determined by: VF = cos(VRMA)power	Double

Codebeispiel

VfCos example 1 (Python window)

Demonstrates how to create a VfCos 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 = VfCos(-15, 15, 1.5)
outDistAccum = DistanceAccumulation("Source.shp", "", "elev.tif",
                                   "cost.tif", "elev.tif",
                                    myVerticalFactor)
outDistAccum.save("C:/sapyexamples/output/distAccumVfC.tif")

VfCos example 2 (stand-alone script)

Performs a DistanceAccumulation analysis using the VfCos class.

# Name: VfCos_Ex_02.py
# Description: Uses the VfCos 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 VfCos Object
lowCutAngle = -15
highCutAngle = 45
cosPower = 2
myVerticalFactor = VfCos(lowCutAngle, highCutAngle, cosPower)

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

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

# Save the output 
outDistAccum.save("C:/sapyexamples/output/distaccumvfC2.tif")