Map Overlay
Overlays are objects (which only Inherits from AGOverlay Interface) on the map
that are set at a coordinates in the map, so they move when you drag or zoom the
map. You also can write a customize overlay object and add it to the map
which is treated like other overlays.
Each overlay implements the AGOverlay interface. Overlays can be
added to a map using the AGMap.addOverlay() method and removed
using the AGMap.removeOverlay() method
Different kind of overlays are given in the following:
Overlay Classes: