Combining multiple rasters

The Combine tool takes multiple input rasters and assigns a new value for each unique combination of input values in the output raster. The original cell values from each of the inputs is recorded in the attribute table of the output raster. Additional items are added to the output raster's attribute table—one for each input raster.

The names of the input rasters are respectively assigned to the field names. Each of these fields carries the unique input combination of values from the input rasters that produces the output value. These items retain the parentage that was used to produce the values for the output raster.

Example

For example, suppose you have two input rasters: InRas1 and InRas2. InRas1 has values ranging from 0 to 10, and InRas2 has values ranging from 0 to 21. If you combine the two input rasters using the Combine tool, the output attribute table could appear something like the following:

Section of example output attribute table from Combine

Value	Count	InRas1	InRas2
1	12	0	153
2	43	100	151
3	28	110	159
4	57	103	0
5	2	100	156
...	...	...	...

Note:

The number of inputs to Combine is limited to 20. Within this constraint, consider that if there are many input rasters with many different zones, potentially a very large number of unique combinations could be created, resulting in a large attribute table and consumption of system resources.