By default, the range for a color ramp is set to the range of the color variable. The MINLEGENDVALUE= and MAXLEGENDVALUE= options enable you to override the default range with your own range. When one or both of the MINLEGENDVALUE= and MAXLEGENDVALUE= options are used, the range is computed as shown in the following table.

If you specify a custom range and the value of the color variable falls outside of the specified range, the tile or tiles associated with the out-of-range color value are colored gray.