shaded relief

Is this a ridge or a canyon? Relief inversion plays tricks on the brain with this image of the Colorado River in Arizona. Photo: NASA

Relief Inversion

Caitlin Dempsey

Telling the difference between a canyon and a mountain on aerial or satellite imagery can sometimes be tricky due to an optical illusion known as relief inversion.

Natural-color Shaded Relief Maps by Hal Shelton

Caitlin Dempsey

Hal Shelton is a cartographer most notable for his natural-color maps done for Jeppeson Map Company in the 1950s and 1960s.