If you call a solar installer to explore putting a solar system on the roof of your home or business, they'll likely plug your address into Google Maps, zoom into your building, and tell you if your roof has enough sun for solar.
Now, there's a tool that goes much further. It's called "Solar Energy from Existing Structures" (SEES) will be available free to companies and municipalities.
Researchers at Sweden's University of Gothenburg developed a tool that can hone in on the maximum sun a roof, neighborhood, or even a whole town can get.
It looks at factors such as the roof's gradient, the angle of sunlight that hits it, and how much shadow it receives from surrounding buildings and vegetation. Putting these factors together, an installer can calculate how much sun a roof will receive for each month over the course of a year.
SEES is based on computer-based geographical information systems (GIS) that collect, store, analyze and present geographical data. It puts a roof in context of its surroundings.