Least Cost Corridor function

Available with Image Server

Calculates the sum of two accumulative cost distance rasters with the option to apply a threshold based on percentage or accumulative cost.

This is a global raster function.

Notes

The input rasters should be distance accumulation and back direction rasters output from the Distance Accumulation or Distance Allocation function. These should be based on cost distance, and the same parameter settings should be used when creating the layers for each source. No parameters that depend on directionality (horizontal factor, vertical factor, and travel direction) should be used in creating these rasters.

The values in the output corridor raster are the sum of the accumulative cost to reach a given location with the same units as the input accumulative cost distance rasters.

If a specified Threshold value is greater than the maximum accumulative cost when the two distance accumulation rasters are summed, the output corridor raster will cover the same area as the input accumulative rasters.

If a specified threshold value is less than the minimum value in the corridor raster, a warning message is returned, and the output raster will be empty.

The output corridor raster may contain cells with slightly greater accumulative costs than the threshold value. This is from the back direction rasters using cells assigned slightly higher costs than the threshold to connect disconnected cells to the corridor. For additional information, see Connect locations with corridors.

Parameters

Parameter name	Description
Input Accumulative Cost Distance Raster 1 (Required)	The input raster representing accumulative cost distance from the first source. It should be an accumulated cost distance output from the Distance Accumulation or Distance Allocation function.
Input Back Direction Raster 1 (Required)	The input back direction raster from the first source. This is a raster dataset identifying the direction of the next cell along the least-cost path back to the first source. This is output from the Distance Accumulation or Distance Allocation function.
Input Accumulative Cost Distance Raster 2 (Required)	The input raster representing accumulative cost distance from the second source. It should be an accumulated cost distance output from the Distance Accumulation or Distance Allocation function.
Input Back Direction Raster 2 (Required)	The input back direction raster from the second source. This is a raster dataset identifying the direction of the next cell along the least-cost path back to the first source. This is output from the Distance Accumulation or Distance Allocation function.
Threshold Method	Specifies how the threshold will be defined. No Threshold—No threshold will be applied, and the resulting corridor will cover the full extent of the input rasters. This is the default. Percent of Least Cost—The threshold will be defined as a percent of the minimum value of the summed accumulative cost distance rasters. Accumulative Cost—The threshold will be defined in accumulative cost distance units.
Threshold	A percent or accumulative cost threshold that will determine whether a given cell will be included in the output corridor raster. When the Threshold method parameter is set to Percent of least cost, the specified value indicates the percent increase to apply from the minimum value of the summed accumulative cost distance rasters. When the Threshold method parameter is set to Accumulative cost, the value indicates cells that have a summed accumulative cost equal to or below the value that will be included in the corridor. This parameter is only active if the Threshold method parameter is set to Percent of least cost or Accumulative cost.