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:

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

To measure the dispersion in a more precise way, use the Inter-Quartile Area and Index of Dispersion:

• 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: