I'm creating a shaded polygon map that displays crime data for several cities and towns in a particular state. The polygons representing each community are shaded based on the number of crimes reported to police within the past year. I'm using a quick filter to toggle which type of crime data is displayed on the map (i.e. robberies, thefts, assaults).
My data only includes crime reports for about 200 of the 300+ communities in this state. When the filter is applied, communities for which no data exists drop off the map (because they are NULL values). Is there a way to force Tableau to continue displaying these communities? I'd like the polygons to appear on the map, shaded in grey or some other color to signify no data was available.