Animated mapping is the application of animation, either a computer or video, to add a temporal component to a map displaying change in some dimension. Most commonly the change is shown over time, generally at a greatly changed scale (either much faster than real-time or much slower). An example would be the animation produced after the 2004 tsunami showing how the waves spread across the Indian Ocean.
The concept of animated maps began in the 1930s but did not become more developed by cartographers until the 1950s.[1] In 1959, Norman Thrower published Animated Cartography, discussing the use of animated maps in adding a new dimension that was difficult to express in static maps: time. These early maps were created by drawing "snap-shots" of static maps, putting a series of maps together to form a scene, and creating animation through photography tricks (Thrower 1959). Such early maps rarely had an associated scale, legends or oriented themselves to lines of longitude or latitude.[2]
With the development of computers in the 1960s and 1970s, animation programs were developed allowing the growth of animation in mapping. Waldo Tobler created one of the first computer-generated map animations, using a 3-D computer-generated map to portray population growth over a specified time in Detroit.[3] Hal Moellering created another animated map in 1976 representing a spatiotemporal pattern in traffic accidents.[1]
Further development in the animated maps was stalled until the 1990s due to a lack of animation in academics, financial restrictions on research, and lack of distribution means.[2] In the 1990s, however, the invention of faster, more efficient computers, compact discs, and the Internet solved such problems. Today, there are many free options for hosting animated maps online, including YouTube and GitHub. Internet GIS and web mapping both make extensive use of animated maps, particularly when showing time. Because of the nature of the internet, this may lead to the distribution of misinformation and contribute to the infodemic.[4][5][6]
With the growth of animated mapping came the development of guidelines for creating animated maps. Visual variables such as spacing, lightness, and shape used for static maps apply. However, in 1991, David DiBiase and colleagues developed visual variables unique to animated maps: duration, rate of change, and order.[7] Duration is the unit of time a frame or scene is displayed, affecting the smoothness of the animation. The shorter a frame is displayed, the smoother the animation will appear.[1] Smoothness of animation is also a function of the rate of change.[1] Order refers to the time sequence in which animation is played out, usually presented in chronological sequence.[1] Alan MacEachren extended these visual variables in 1995 to include display date (time at which change is initiated), frequency (number of times identifiable forms are displayed), and synchronization (correspondence of 2 or more time series).[1]
Animated maps can emphasize the existence of an occurrence at a location, emphasize an attribute of an occurrence, or represent a change in the position or attributes of an occurrence.[7] For instance, a flashing symbol may be used to draw the map-reader's attention to a particular occurrence at one location or multiple locations across the map. Maps on the weather channel use animation to emphasize the current and predicted paths of hurricanes.