Overlays are objects on the map that are bound to latitude/longitude coordinates.
Google Maps has several types of overlays:
- Marker - Single locations on a map. Markers can also display custom icon images
- Polyline - Series of straight lines on a map
- Polygon - Series of straight lines on a map, and the shape is "closed"
- Circle and Rectangle
- Info Windows - Displays content within a popup balloon on top of a map
- Custom overlays
