Dot Density Theme

Dot density themes use dots to represent the data value associated with a boundary or region. The total number of dots in a region represents that region's data value. If you have 10,000 senior citizens in a county, and each dot represents 100 senior citizens, there would be 100 dots in the county boundary.

Dot density is particularly useful for showing raw data where one dot represents a large number of something: population, number of fast food restaurants, number of distributors who carry a brand of soda, etc.

Distribution of dots is random within the region. If you shade states according to population, the dots for New York are spread out throughout the state; they are not concentrated in New York City, where the majority of the state's population lives.

Named Layer with Dot Density Theme

A dot density theme is a style modifier theme called a FeatureStyleDotDensityTheme. The schema is contained in MXP_MapTheme_1_5.xsd. A dot density theme is stored in the Spectrum Spatial repository as part of a named layer. The theme is defined by an expression whose value is the density for each feature; a value per dot, and a dot style.

Dot density themes contain optional data for defining an associated legend, including style overrides and controlling visibility. For the schema see MXP_MapLegend_1_5.xsd.


A dot density map example.