Interactive & Multiscale Thematic Maps: A Preliminary Study

Abstract. Problem: Interactive or “slippy” web maps have revolutionized cartography. Slippy maps present a single, coherently-designed reference map that can be panned to numerous geographic locations and zoomed across multiple scales. Further, they apply scale-dependent style rules to detailed geographic datasets, with the resulting designs rendered as a large set of interlocking tiles. To account for constraints in data bandwidth, processing, and storage, only those tiles relevant to the user’s location and past interactions are served into the web browser or other application, resulting in a seamless, real-time user experience of “a map of everywhere”. These slippy tilesets often are used as basemaps for advanced cartographic web and mobile applications, overlaying thematic information and other linework. Arguably, such slippy map mashups are the most common map seen and used today (and perhaps of all time). Yet, most of the cartographic design canon was developed long before slippy maps were possible. Do any of our time-tested design traditions in thematic cartography apply in today’s interactive and multiscale mapping context? In this presentation, we discuss preliminary insights from an online map study about the design of interactive and multiscale thematic maps.