Increase the maximum number of unique values allowed in a raster attribute table

Summary

When a raster dataset that has more than 65,536 unique values is rendered, an error message may display that there are too many unique values. Instructions provided describe how to increase the maximum number of unique values allowed in a raster attribute table.

Procedure

To edit the unique values for a raster attribute table, follow the steps below:

1. In ArcMap, click Customize > ArcMap Options.
2. In the ArcMap Options dialog box, click the Raster tab, and click the Raster Dataset sub-tab.
3. In the Maximum number of unique values to render parameter, insert the desired maximum number of unique values.

Note:
By default, the size of a raster attribute table is limited to 65,535 unique values. 

4. Click OK.