**If you mean the center of a polygon:**

*Regular Polygon case:*

In the case of regular polygons the center is the point that is equidistant from each vertex or corner. It is also the center of the polygon's incircle and circumcircle.

*Irregular Polygon case*

Irregular polygons are not considered as having a center, since there is unlikely to be any one point equally distant form each vertex. However, an irregular polygon can have a centroid, or center of gravity.

**If you mean the centroid of a polygon**see this article: http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/[^].

**You can also calculate a vector mean**, by calculating a mean for longitude and latitude values respectively.