Harvesting Water with Google Maps

Save the Rain is a great application that helps users determine how much rainfall can be harvested from any roof in the world.

Using Google Maps satellite imagery of your house it is possible to draw a polygon on the map to determine the area of your roof. The application then uses the yearly precipitation data for your area to work out how much rainwater you could harvest in a year.

The results also display a number of different types of crops and tells you how much you could grow of each crop with the water harvested.

In addition to the water harvesting calculation tool Save the Rain provides a number of rain related choropleth map views. One map view displays worldwide annual rainfall. Another map view shows the projected change in annual precipitation by 2100. A third map view displays the percentage of the world's population with access to an adequate amount of water.