Editing Animated mapping (section)

==Visual variables==
{{main | Visual variable}}
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.<ref name=DiBiase1991>{{cite journal |last=DiBiase |first=David |display-authors=etal |date=1992 |title=Animation and the role of map design in scientific visualization |journal=Cartography and Geographic Information Systems |volume=19 |issue=4 |pages=201–214, 165–266 |doi=10.1559/152304092783721295 |bibcode=1992CGISy..19..201D |url=https://www.researchgate.net/publication/243777859}}</ref> 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.<ref name=Slocum/> Smoothness of animation is also a function of the rate of change.<ref name=Slocum/> Order refers to the time sequence in which animation is played out, usually presented in chronological sequence.<ref name=Slocum/> [[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).<ref name=Slocum/>