ion and abstraction. By the end of the 20th century, technology had advanced to the point where computerized methods had revolutionized surveying and mapmaking practices. Now, the map's purpose drives the design, and possible errors in scale are intentional. These maps portray the environment in two dimensions, using a local rectangular coordinate system. Thematic maps lack geographic features, visualizing spatial variations of distributions of selected properties, such as population densities. Cadastral maps emphasize ownerships, road maps focus on the street topology, and tourist maps simplify the environment for navigational use, sometimes annotating the map with landmark figures. But the development has not stopped. Digital tools now let modern cartographers increase realism with unprecedented ease. For example, the US National Park Service, which produces maps for 300 million annual visitors, has continuously increased realism in pursuit of transforming map use to "becom...