HfInverseLinear
摘要
Defines the relationship between the horizontal cost factor and the horizontal relative moving angle through an inverse linear function. The function specifies that the horizontal factor is an inverse linear function of the horizontal relative moving angle.
插图
讨论
The HfInverseLinear object is used in the Spatial Analyst tools Path Distance, Path Distance Allocation, and Path Distance Back Link.
The horizontal factors (HF) are determined by the inverse values from a straight line in the horizontal relative moving angle (HRMA)-HF coordinate system. The line intercepts the y-axis, equitable to the HF factor, at the value associated with the zerofactor. The slope of the line can be specified with the slope modifier. If no slope is identified, the default is -2/180 or -1/90 (specified as -0.01111).
语法
参数 | 说明 | 数据类型 |
zeroFactor |
The zeroFactor will be used to position the y-intercept of the inverse linear function. (默认值为 2.0) | Double |
cutAngle |
The cutAngle establishes the HRMA degree threshold beyond which the HFs are set to infinity. (默认值为 180.0) | Double |
slope |
Identifies the slope of the straight line in the HRMA-HF coordinate system. Slope is specified as the rise over the run. For example, a 30-degree slope is 1/30, specified as 0.03333 (rise/run: 1 HF on the y axis / 30 degrees on the x axis). (默认值为 -0.011111) | Double |
属性
属性 | 说明 | 数据类型 |
cutAngle (可读写) |
The cutAngle establishes the HRMA degree threshold beyond which the HFs are set to infinity. When the HRMA is less than the cut angle then the zero factor is assigned and when the HRMA is greater than the cut angle, infinity is assigned. | Double |
zeroFactor (可读写) |
The zeroFactor will be used to position the y-intercept of the function. The zeroFactor is assigned as the horizontal factor when HRMA is less then the cut angle. | Double |
slope (可读写) |
Identifies the slope of the straight line in the HRMA-HF coordinate system. Slope is specified as the rise over the run. For example, a 30-degree slope is 1/30, specified as 0.03333 (rise/run: 1 HF on the y axis / 30 degrees on the x axis). | Double |
代码示例
Demonstrates how to create an HFInverseLinear class and use it in the PathDistance tool within the Python window.
import arcpy from arcpy import env from arcpy.sa import * env.workspace = "C:/sapyexamples/data" myHorizFactor = HfInverseLinear(2.0, 181.0, -0.01111) outPathDist = PathDistance("source.shp", "costraster", "", "", myHorizFactor) outPathDist.save("C:/sapyexamples/output/pathdisthfil")
Performs a PathDistance analysis using the HFInverseLinear class.
# Name: HfInverseLinear_Ex_02.py # Description: Uses the HfInverseLinear object to execute the PathDistance 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" # Create the HfInverseLinear Object zeroFactor = 2.0 cutAngle = 181.0 slope = -0.01111 myHorizFactor = HfInverseLinear(zeroFactor, cutAngle, slope) # Check out the ArcGIS Spatial Analyst extension license arcpy.CheckOutExtension("Spatial") # Execute PathDistance outPathDist = PathDistance(inSourceData, inCostRaster, "", "", myHorizFactor) # Save the output outPathDist.save("C:/sapyexamples/output/pathdisthfil2")