An overview of the Local toolset
The local tools are those where the value at each cell location on the output raster is a function of the values from all the inputs at that location.
To perform the calculation, a local tool only needs, for each of the input rasters, the value at that location, as well as (in some cases) a comparison value. Once the result is generated, the calculation is made for the next cell location, and the process is iterated until all cells have been processed.
With the local tools, you can combine the input rasters, calculate a statistic on them, or evaluate a criterion for each cell on the output raster based on the values of each cell from multiple input rasters.
There are five general categories of analysis that local tools perform:
 Calculate a statistic for each location (for example, the minimum value).
 Assign a unique value for each unique combination of values at each location.
 Assign the number of times the cell location input values for the location meet a specified criterion relative to another input value.
 Assign the value at the cell location that meets a specified criterion relative to other input values.
 Assign the position of the raster containing the cell value that meets a specified criterion relative to another input value.
The following table lists the available Local toolset tools and provides a brief description of each.
Tool 
Description 

Calculates a percell statistic from multiple rasters. The available statistics are Majority, Maximum, Mean, Median, Minimum, Minority, Range, Standard Deviation, Sum, and Variety. 

Combines multiple rasters so that a unique output value is assigned to each unique combination of input values. 

Evaluates on a cellbycell basis the number of times the values in a set of rasters are equal to another raster. 

Evaluates on a cellbycell basis the number of times a set of rasters is greater than another raster. 

Determines on a cellbycell basis the position of the raster with the maximum value in a set of rasters. 

Evaluates on a cellbycell basis the number of times a set of rasters is less than another raster. 

Determines on a cellbycell basis the position of the raster with the minimum value in a set of rasters. 

Determines the value in an argument list that is at a certain level of popularity on a cellbycell basis. The particular level of popularity (the number of occurrences of each value) is specified by the first argument. 

The values from the set of input rasters are ranked on a cellbycell basis, and which of these gets returned is determined by the value of the rank input raster. 