Create Constant Raster (Spatial Analyst)

Summary

Creates a raster of a constant value within the extent and cell size of the analysis window.

Illustration

OutRas = CreateConstantRaster(2)

Usage

• The Create Constant Raster tool assigns the specified value to every cell in the output raster.

• The constant value must be a numeric value. Scientific notation is acceptable (for example, 3.048e^-4).

• Some typical reasons for creating a raster of all the same values include:

  • A Mask environment has been set and you want a raster identifying all unmasked cells to use in a variety of other tools (for example, as a condition raster in the Con tool).
  • You want all the values in an output raster from a mask or some selection process to be classified as a single value.
  • You want to apply a constant value in an analysis to all cell locations in another raster—for example, you want to add five decibels to each location in a noise pollution raster.

Syntax

CreateConstantRaster (constant_value, {data_type}, {cell_size}, {extent})

Parameter	Explanation	Data Type
constant_value	The constant value from which to create an output raster dataset.	Double
data_type (Optional)	Data type of the output raster dataset. INTEGER—An integer raster will be created. FLOAT—A floating-point raster will be created. If the specified data type is FLOAT, the input constant value is only accurate to 7 decimal places (single precision).	String
cell_size (Optional)	The cell size for the output raster dataset. This is the value in the environment if specifically set. If not specifically set, it is the shorter of the width or height of the environment extent in the output spatial reference, divided by 250.	Analysis Cell Size
extent (Optional)	The extent for the output raster dataset. The Extent is a Python class. In this tool it is in the form of: Extent(XMin, YMin, XMax, YMax) where XMin and YMin define the lower-left coordinate of the extent, with XMax and YMax defining the upper-right coordinate. The coordinates are specified in the same map units as the in_raster. The extent will be the value in the environment if specifically set. If not specifically set, the default is 0, 0, 250, 250.	Extent

Return Value

Name	Explanation	Data Type
out_raster	The output raster for which each cell will have specified constant value.	Raster

Code Sample

CreateConstantRaster example 1 (Python window)

This sample creates a float raster of a particular value at the defined cell size and extent.

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outConstRaster = CreateConstantRaster(12.7, "FLOAT", 2, Extent(0, 0, 250, 250))
outConstRaster.save("C:/sapyexamples/output/outconst2")

CreateConstantRaster example 2 (stand-alone script)

This sample creates an integer raster of a particular value at the defined cell size and extent.

# Name: CreateConstantRaster_Ex_02.py
# Description: Creates a raster from a constant value
# Requirements: Spatial Analyst Extension
# Author: ESRI

# Import system modules
import arcpy
from arcpy.sa import *

# Set local variables
constantValue = 12
cellSize = 2
outExtent = Extent(0, 0, 250, 250)

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

# Execute CreateConstantRaster
outConstRaster = CreateConstantRaster(constantValue, "FLOAT", cellSize,
                                      outExtent)

# Save the output 
outConstRaster.save("C:/sapyexamples/output/outconst")

Environments

Cell Size, Current Workspace, Mask, Output Coordinate System, Extent, Scratch Workspace, Snap Raster

Licensing Information

ArcView: Requires Spatial Analyst

ArcEditor: Requires Spatial Analyst

ArcInfo: Requires Spatial Analyst