The Median Center is the cartographic equivalent of the center of
gravity in geometry. It's a very simple way to determine where most
of the points are clustered, and is applicable to any geographical feature that
forms a point distribution
(ie, NOT a line or area), such as distribution of cities, factories, shops, high-rise buildings, etc. To find the Median Center:

Limitation: the Index of Dispersion will NOT indicate if there are several small clusters, such as on this population dot map below:

- Plot the points on a map
- Draw a line North-South leaving an equal number of points on each side (left/right)
- Draw a line East-West leaving an equal number of points on each side (top/bottom)
- The intersection of both lines is the Median Center.

- Id = 0: highly clustered
- Id = 0.25: uniform
- Id = 1: completely dispersed

Limitation: the Index of Dispersion will NOT indicate if there are several small clusters, such as on this population dot map below: