The Google Maps Drawing Manager provides a control for drawing
markers, polylines, circles, rectangles, and polygons on the map.
the markup is complete, we can use the other methods of the Maps API to extract
data from the shapes, such as coordinates, center, radius, or bounding box,
depending on the type of shape.
Having extracted these data, we can then send the data to a server-side
program to store them in a spatial database.