I dont know if this is possible but I use a google map to plot out positions of entities via markers on an overlay. I would like to be able to create a polygon or some other sor
I think you are looking for the Convex Hull of the points
In mathematics, the convex hull or convex envelope of a set X of points in the Euclidean plane or Euclidean space is the smallest convex set that contains X. For instance, when X is a bounded subset of the plane, the convex hull may be visualized as the shape enclosed by a rubber band stretched around X.
Example using the Google Maps API v3 on a random set of points