How Big is Google Maps?

Recently the Google Maps API added the option to allow polygon shapes on Google Maps to be set to draggable. If the polygon property is set to true, the user can then drag the shape over the map.

Google created a popular game, they called Mercator Puzzle, to demo the new draggable polygon option. The game set the geodesic property of the polygons to true, which means the game provides a great insight into the Mercator projection. It is very noticeable in the game how the polygons resize as you drag north and south on the map.

How big is Lake Tanganyika, Tanzania? also makes use of draggable polygons with the geodesic property of the polygons set to true. In this case it allows the user to drag a polygon of Lake Tanganyika around on Google Maps and see how it compares in size when placed over other locations.

The app comes with all the code so you can create your own example using shape files of other locations. The effect is very similar to (and is even called a 'customisable mimic' of) the BBC's Dimensions project How Big Really?.

The BBC Dimensions projects allows you to move polygons of important places and events around on Google Maps and overlay them on other locations to help give you a sense of scale of these locations.