Researchers at the Universidad Coplutense de Madrid are studying light pollution and the energy consumption derived from it using images taken from the International Space Station (ISS)—provided by Earth Science and Remote Sensing Unit, NASA-Johnson Space Center.
 
To compare the images with the different light sources on the earth, they need to know the city's location. Due to the large number of images, the researchers are reaching out to citizen scientists for help identifying the different cities photographed.
 
The process: An ISS image will be loaded in the left panel and a map on the right one. The aim is try to identify the city. Citizen scientists have some simple tools at their disposal, including zooming in and out, dragging, and rotating the image. When a picture is identified, the citizen scientist clicks on the map to mark its position.