** (Power) operator

Available with Spatial Analyst license.

Available with Image Analyst license.

Summary

Raises the cell values in a raster to the power of the values found in another raster.

Illustration

Power illustration
OutRas = Raster("InRas1") ** 2

Discussion

When using an operator with a raster input, the result will be a raster. However, if all inputs are numbers, the result is a number.

When multiple operators are used in an expression, they are not necessarily executed in left-to-right order. The operator with the highest precedence value will be executed first. For more information, see the operator precedence table in Working with operators in Map Algebra. You can use parentheses to control the execution order.

Output values are always floating point, regardless of the input value type.

Another way to perform the power operation is a **= b, which is an alternative way to write a = a ** b.

If both inputs are single-band rasters, or one of the inputs is a constant, the output will be a single-band raster.

If both inputs are multiband rasters, the operator will perform the operation on each band from one input, and the output will be a multiband raster. The number of bands in each multiband input must be the same.

If one of the inputs is a multiband raster and the other input is a constant, the operator will perform the operation against the constant value for each band in the multiband input, and the output will be a multiband raster.

If both inputs are multidimensional rasters with same number of variables, the operator will perform the operation for all slices with same dimension value, and the output will be a multidimensional raster. The variables in the inputs must have same dimensions or common dimension but no uncommon dimensions.

If both inputs have one variable but different names, set the matchMultidimensionalVariable geoprocessing environment to False to perform the operation.

If one of the inputs is a multidimensional raster and the other input is a constant, the operator will perform the operation for all slices for all variables against the constant value, and the output will be a multidimensional raster.

Parameters

OperandExplanationData Type
in_raster_or_constant1

The input values to be raised to the power defined by the second input.

If the first input is a raster and the second is a scalar, an output raster is created with each input raster value being raised to the power of the scalar value.

Raster Layer | Constant
in_raster_or_constant2

The input that determines the power to which the values in the first input will be raised.

If the first input is a scalar and the second is a raster, an output raster is created with the scalar value being raised to the power of each input raster value.

Raster Layer | Constant

Code sample

** (Power) example 1 (Python window)

This sample uses the values in the second input raster as the power by which to raise the values in the first input raster.

import arcpy
from arcpy import env
from arcpy.ia import *
env.workspace = "C:/iapyexamples/data"
outPower = Raster("degs") ** Raster("cost")
outPower.save("C:/iapyexamples/output/outpower.img")
** (Power) example 2 (stand-alone script)

This sample uses the values in the second input raster as the power by which to raise the values in the first input raster.

# Name: Op_Power_Ex_02.py
# Description: Raises the cells in a raster to the power of the values
#              found in another raster
# Requirements: Image Analyst Extension

# Import system modules
import arcpy
from arcpy import env
from arcpy.ia import *

# Set environment settings
env.workspace = "C:/iapyexamples/data"

# Set local variables
inRaster1 = Raster("degs")
inRaster2 = Raster("cost")

# Execute Power
outPower = inRaster1 ** inRaster2

# Save the output 
outPower.save("C:/iapyexamples/output/outpower")

Related topics