Excel maps with NULL data

[rzrbaxfan]

I'm exploring the idea of using Excel as a dashboard for generating maps.  I'd like the map to be of an entire state showing counties, but be able to shade counties with no data to seperate them from counties that have reported data, but that data is zero.  If I leave the data blank in the cell that the map is generated from, it fills in a zero on the map.  I've tried putting "NULL" and even deleted the row that the 'no data' county came from....but the map still shows the county as zero.

Does anyone have a workaround to seperate "no data reported" counties from "county reported 0" counties in Excel maps?

[#2]

@rzrbaxfan Use the error value #N/A in the data-series cells with no data (type It without quotes). To derive that value in a formula, use the NA function, for example:

=IF( ISBLANK(C2), NA(), C2 )