# VfSecCos

Disponible avec une licence Spatial Analyst.

## Synthèse

Defines the relationship between the vertical cost factor and the vertical relative moving angle (VRMA) through a secant/cosine function. If the VRMA is negative the vertical factor is defined by a secant function, and if the VRMA is nonnegative the vertical factor is defined by a cosine function.

## 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 a negative degree value, the VF is determined by the cosine function of the VRMA. If the VRMA is a positive degree value, the VF is determined by the secant function of the VRMA.

## Syntaxe

`VfSecCos ({lowCutAngle}, {highCutAngle}, {secPower}, {cosPower})`
 Paramètre Explication Type de données lowCutAngle The VRMA degree defining the lower threshold, below which (less than) the VFs are set to infinity (La valeur par défaut est -90.0) Double highCutAngle The VRMA degree defining the upper threshold, beyond which (larger than) the VFs are set to infinity.(La valeur par défaut est 90.0) Double secPower The power to which the values in the secant VRMA function will be raised. The VF is determined by: `` VF = sec(VRMA)power``(La valeur par défaut est 1.0) 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``(La valeur par défaut est 1.0) Double

## Propriétés

 Propriété Explication Type de données 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 secPower(Lecture et écriture) The power to which the values in the secant VRMA function will be raised. The VF is determined by:`` VF = sec(VRMA)power`` Double cosPower(Lecture et écriture) The power to which the values in the cosine VRMA function will be raised. The VF is determined by:`` VF = cos(VRMA)power`` Double

## Exemple de code

VfSecCos example 1 (Python window)

Demonstrates how to create a VfSecCos 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 = VfSecCos(-90, 90, 1, 1)
outDistAccum = DistanceAccumulation("Source.shp", "", "elev.tif",
"cost.tif", "elev.tif",
myVerticalFactor)
outDistAccum.save("C:/sapyexamples/output/distAccumVSC.tif")``````
VfSecCos example 2 (stand-alone script)

Performs a DistanceAccumulation analysis using the VfSecCos class.

``````# Name: VfSecCos_Ex_02.py
# Description: Uses the VfSecCos 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 VfSecCos Object
lowCutAngle = -90
highCutAngle = 90
secPower = 1
cosPower = 1
myVerticalFactor = VfSecCos(lowCutAngle, highCutAngle, secPower, 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/distaccumvfSC2.tif")``````