# Arithmetic

## Synthèse

Performs an arithmetic operation between two rasters or between a raster and a scalar and returns a raster object with the operation applied.

## Syntaxe

`Arithmetic (raster1, raster2, {operation_type}, {extent_type}, {cellsize_type})`
 Paramètre Explication Type de données raster1 The first input raster. This can be a scalar raster where all pixels have the same value. Raster raster2 The second input raster. This can be a scalar raster where all pixels have the same value. Raster operation_type The arithmetic operation to apply between the two input rasters.Divide—Outputs the divisible result between the corresponding pixel values for each raster.Minus—Outputs the difference between the corresponding pixel values for each raster. This operation can be used to calculate change detection.Mode—Outputs the pixel value of all overlapping pixels that occurs the most. For example, if there are six bands in a raster, there will be six overlapping pixels. For the values 4, 5, 6, 4, 7, 9, the mode value is 4.Multiply—Outputs the product of the corresponding pixel values for each raster. This operation can be used to perform some cost functions.Plus—Outputs the sum of all the corresponding pixel values for each raster.Power—Outputs the product of the corresponding pixel values raised to the power of the input raster or scalar.(La valeur par défaut est Plus) String extent_type The method to use to compute the extent of the output when the input rasters have different extents.FirstOf—The output extent is defined using the extent of the first input raster.LastOf—The output extent is defined using the extent of the last input raster.IntersectionOf—The output extent is defined as the intersecting area of the input rasters.UnionOf—The output extent is defined as the total extent of the input rasters.(La valeur par défaut est FirstOf) String cellsize_type The method to use to compute the cell size of the output when the input rasters have different cell sizes. FirstOf—The output cell size is defined using the cell size of the first input raster.LastOf—The output cell size is defined using the cell size of the last input raster.MaxOf—The output cell size is defined using the maximum cell size of the input rasters.MeanOf—The output cell size is defined using the mean of both input rasters.MinOf—The output cell size is defined using the minimum cell size of the input rasters.(La valeur par défaut est FirstOf) String
Valeur renvoyée
 Type de données Explication Raster The output raster with the arithmetic operation applied.

## Exemple de code

Arithmetic example

Multiplies two rasters and uses the total extent of the inputs.

``````import arcpy

new_raster = arcpy.ia.Arithmetic("Raster1.tif","Raster2.tif", "Multiply", "UnionOf", "FirstOf")``````