Represents a dot density symbol renderer definition to show quantitative values for a
field as a series of pattern fills based on the field value for each polygon.
With dot density symbology, the data you symbolize is not classified.
Instead, quantitative values for one or more fields are represented as a
collection of point symbols (typically solid circles or dots) within each polygon.
Each dot represents a constant number of things, or people, or other quantifiable phenomena.
The dots are equally sized, even when multiple fields are symbolized together within a layer.