As the foregoing chapters indicate, a recurring theme in map history is the graphic portrait of change from one spatial pattern to another. A geographic ‘change of state’, to borrow a term from chemistry and atomic physics, might be as cartographically straightforward as when an election alters power relationships and produces a new pattern of local or regional electoral dominance. The simplest case is the juxtaposition of two maps, to show the old and the new, or the before and the after. If provincial boundaries are static, these maps are akin to chessboard diagrams depicting the locations of queens, bishops, and other chess pieces at different stages of a game, which makes it appropriate to call them chess maps. This chapter attempts to codify narrative cartography by identifying a set of distinctive types of change-of-state maps. It concludes with a few suggestions for further research.

Although a mere pair of chess maps can describe a noteworthy shift, three or more maps representing the outcomes of successive elections can sustain a longer, more interesting narrative such as a story of progressive, far-reaching change or an oscillation of control, as when a political party achieves dominance, falters and loses control, and then rebounds. Arranged in temporal order like a series of snapshots, chess maps can emphasize a simple explanation or introduce a potentially richer story in which a verbal narrative is supplemented by statistical graphics, photographs, and other maps.