How would I make a polygon based on the relative positions of markers in google maps?

Question

I have a list of markers that I want to create a polygon around (showing the area around the markers and not the markers themselves). So instead of having the poly points be

Answer 1

This is called a convex hull. There's an example at http://www.geocodezip.com/v3_map-markers_ConvexHull.asp which uses the algorithm described at http://softsurfer.com/Archive/algorithm_0203/algorithm_0203.htm