This slideshow form Popular Science takes a step-by-step look at how to detect and uncover ancient buried settlements from satellite imagery.
"Lots of people live in Egypt. They always have. So how do you find ancient ruins when modern humans live and farm the land? Sarah Parcak of the University of Alabama at Birmingham uses images from a hyperspectral satellite, which has cameras that take pictures in various wavelengths. She sorts the data to reveal the high concentrations of organic matter and phosphorus content that mark ancient Egyptian house mounds. Then she gets a closer look and starts to dig."