Measuring Map Complexity

In this paper, issues of complexity and their application to cartographic practice and enquiry are addressed. After an initial discussion of the nature of complexity and its fitful study in cartography over recent years, an assessment is made of the potential for quantifying map complexity. A series of practical tests was devised and is described. These consider a wide range of metrics, including spatial statistical measures, entropy and image-based indices. Their application to both raster and vector mapping is investigated. Data compression shows promise as an index which can be used to characterize the graphical variation within the map face. The nature of digital data compression is described, with reference to raster map representations, and it is determined that a data-compression ratio can act as a simple and effective complexity measure. The paper concludes by listing some of the reasons why complexity, as measured by data compression, could be used in cartographic practice.