Greg Miller, National Geographic, September 16, 2016:  “The world’s most beautiful places are rarely flat. From the soaring peaks of the Himalaya to the vast chasm of the Grand Canyon, many of the most stunning sites on Earth extend in all three dimensions. This poses a problem for mapmakers, who typically only have two dimensions to work with. Fortunately, cartographers have some clever techniques for creating the illusion of depth, many of them developed by trial and error in the days before computers. The best examples of this work use a combination of art and science to evoke a sense of standing on a mountain peak or looking out an airplane window. One of the oldest surviving maps, scratched onto an earthenware plate in Mesopotamia more than 4,000 years ago, depicts mountains as a series of little domes. It’s an effective symbol, still used today in schoolchildren’s drawings and a smartphone emoji, but it’s hardly an accurate representation of terrain. Over the subsequent centuries, mapmakers made mostly subtle improvements, varying the size and shape of their mountains, for example, to indicate that some were bigger than others…”