Map Calculator - Save the Rain
(A Google Maps API/ESRI JavaScript API/MapBox/HTML5 Map Mashup)
A very good Map Mashup that calculates the potential yearly yield in corn, soya beans, rice and wheat.
Quick Guide:
Search a location:
Zoom and/or Pan to a clear roof top.
Digitise/Draw the outline of the roof.
Click Finished
The Map calculates the sun/mean rainfall of the location and produces a bar of produce that can grown with the rainfall footprint of the roof.
A Built in Video Tutorial (below) shows how the tool works.
This app can be voted for on https://wbchallenge.imaginatik.com/wbchallengecomp.nsf/x/idea?open&eid=2011111685257879005955D51068264&iid=F96A72C99B48E74A852579C0006B8384&es=0 (login required to vote)