Mushrooms / Facing semi-circles

This representation method shows two stocks (or two values) on a map using two proportional semi-circles.

This method makes it possible to compare two values for each geographical entity.

This method was popularized by Emile Cheysson in 1886.

Parameters

The representation parameters are the same as for proportional symbols, except that it is necessary to choose parameters for two values instead of one.

Reference size

The same logic applies as for proportional symbols of type "circle": the half-circle drawn for the reference value corresponds to half of a full circle whose area would be 10,000 px² for a reference size of 100 px.

Examples

Example of the representation of two stocks (population and GDP)