| Label | Explanation | Data Type | 
| Input raster or constant value 1 | The input whose values will be added to. A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. | Raster Layer; Constant | 
| Input raster or constant value 2 | The input whose values will be added to the first input. A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. | Raster Layer; Constant | 
| Output raster | The output raster. The cell values are the sum of the first input added to the second. | Raster Dataset | 
Available with Spatial Analyst license.
Available with Image Analyst license.
Available with 3D Analyst license.
Summary
Adds (sums) the values of two rasters on a cell-by-cell basis.
Illustration

Usage
- The order of inputs is irrelevant for this tool. 
- If both inputs are integer, the output will be an integer raster; otherwise, it will be a floating-point raster. 
- 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 tool 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 tool will perform the operation using the constant value for each band in the multiband input, and the output will be a multiband raster. 
- If both inputs are multidimensional raster data with the same number of variables, the tool will perform the operation for all slices with the same dimension value. The output will be a multidimensional raster in CRF format. The variables in the inputs must have at least one common dimension and one common dimensional value for this tool to process; otherwise, an error will occur. - If both inputs have one variable but different names, uncheck the Match Multidimensional Variable geoprocessing environment (set arcpy.env.matchMultidimensionalVariable = False in Python) before running the tool. - If one of the inputs is a multidimensional raster and the other input is a constant, the tool will perform the operation for all slices for all variables using the constant value, and the output will be a multidimensional raster. 
Parameters
arcpy.ddd.Plus(in_raster_or_constant1, in_raster_or_constant2, out_raster)
| Name | Explanation | Data Type | 
| in_raster_or_constant1 | The input whose values will be added to. A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. | Raster Layer; Constant | 
| in_raster_or_constant2 | The input whose values will be added to the first input. A number can be used as an input for this parameter, provided a raster is specified for the other parameter. To specify a number for both inputs, the cell size and extent must first be set in the environment. | Raster Layer; Constant | 
| out_raster | The output raster. The cell values are the sum of the first input added to the second. | Raster Dataset | 
Code sample
This example adds the values of two Grid rasters and outputs the result as an IMG raster.
import arcpy
arcpy.env.workspace = "C:/data"
arcpy.ddd.Plus("elevation", 15, "C:/output/outplus.img")This example adds the values of two Grid rasters and outputs the result as a Grid raster.
# Name: Plus_3d_Ex_02.py
# Description: Adds the values of two rasters on a cell-by-cell basis.
# Requirements: 3D Analyst Extension
# Import system modules
import arcpy
from arcpy import env
# Set environment settings
env.workspace = "C:/data"
# Set local variables
inRaster = "elevation"
inConstant = 15
# Execute Plus
arcpy.ddd.Plus(inRaster, inConstant,"c:/output/outplus")Environments
Licensing information
- Basic: Requires 3D Analyst or Spatial Analyst
- Standard: Requires 3D Analyst or Spatial Analyst
- Advanced: Requires 3D Analyst or Spatial Analyst