Create Constant Raster

Overview

This tool creates a raster layer with a uniform value for all valid cells based on the specified analysis extent and cell size. It can be used as a background raster, a mask, or an initialized input for subsequent spatial analysis.

Use Cases

• Initialize constant input parameters in geographic models, such as an initial elevation value.
• Use in calculations with other rasters, such as weighted overlay.
• Create mask or spatial constraint layers.
• Simulate variable effects under uniformly distributed conditions.

Parameters

Parameter	Description	Notes
Constant value	The value assigned to all valid cells in the output raster.	Default: 10
Number of bands	The number of bands in the output raster.	Default: 1
Output type	When saving raster data, you can manually set raster output parameters or use a snap raster to match the parameters of a reference raster.	See common raster output.
Output file	Specifies the storage location, file name, data format, data type, and NoData value of the output raster data.	See common raster output.

Steps

1. Start the tool

   Open the Raster Basic Tools toolbox, go to Raster Data > Create Raster, and start the Create Constant Raster tool pane.

2. Set the raster value

   • Constant value: Enter the target value, such as 50. This value is assigned to all cells.
   • Number of bands: The default is 1.

3. Configure raster spatial properties

   • In the Output type drop-down list, select a configuration mode:
     • Manual input: Manually define the Output coordinate system, spatial Extent, and Cell size.
     • Use vector data: Select an existing vector layer. The system automatically reads its coordinate system and extent.
     • Use raster data: Select a reference raster. The system fully inherits its coordinate system, extent, cell size, and other spatial structure settings.
   • Optionally configure Snap to raster to force the output grid to align exactly with a specific reference raster.

4. Set the output file and raster properties

   • Click the button next to Output file, specify the output path, and enter the file name.
   • Configure Data type based on the value range, such as single-precision floating point or double-precision floating point.
   • Set the NoData value. The default is Auto, but you can customize it for analysis requirements.
   • Select Compression type. Keeping the default LZW compression is recommended to balance storage space and read/write efficiency.

5. Generate the raster

   • Click Run at the bottom of the window.
   • After the task is completed, the constant raster is saved to the specified location and is usually loaded automatically into the current project.

Notes

• Spatial parameters:

  • Set the analysis extent explicitly. It is recommended to obtain it from a layer or enter it manually.
  • Cell size is the raster resolution. A cell size that is too large reduces precision, while one that is too small affects performance and storage efficiency. It should match the analysis requirements.
  • Use the same coordinate system as the objects used in subsequent analysis to avoid offsets in spatial overlay.

• Data properties:

  • The default data type is double-precision floating point. If integer values are used, specify an integer data type to avoid unnecessary precision or value overflow.
  • Enter an explicit input value so that the value meaning is clear.
  • The default NoData value is the maximum value supported by the data type, but you can also enter a custom value.