Research note: Sankey diagrams for visualizing land cover dynamics

Comparison of categorical maps from two or more points in time is a common technique to detect land cover and land use change. Cross-tabulation matrices, which contain information on the sizes of categorical differences between two maps, are often used to describe the amount and type of land cover change that has occurred between two points in time. However, the use of multiple matrices to describe changes occurring over more than one time interval can be difficult to interpret. This article presents a graphical method for presenting the land cover information contained in one or more cross-tabulation matrices based on Sankey diagrams, which depict the flow of energy or materials through a network. Through the example of a series of land cover maps of the San Juan, Puerto Rico area (1999-2003), this form of Sankey diagram is demonstrated to efficiently and elegantly present information on land cover persistence and change over multiple time intervals.