Functional Aesthetics for Data Visualization

CHAPTER 2Perception in Charts

Maps are a type of chart that can convey relationships about space and relationships between objects that we relate to in the real world. Their effectiveness as a communication medium is strongly influenced by a host of factors: the nature of spatial data, the form and structure of representation, their intended purpose, the experience of the audience, and the context in the time and space in which the map is viewed. In other words, maps are a ubiquitous representation of spatial information that we can understand and relate to. Based on the geospatial task we have in mind, effective maps simply work. Take an example during your day when you use a map, subconsciously solving your problem without really giving it too much thought. You are running late to an appointment, but you park your car in the closest available parking spot. You whip out your phone and quickly punch in the address of the office you need to head to. The map application uses the context of your location, where you are standing in space, and assesses that given the proximity of where you are from the office, you are probably walking. Rather than a full-scale map, a walking map shows turn-by-turn directions with an estimated time of arrival that helps you determine your pace. It's a simple yet delightful functional representation that helps you reach your appointment on time.

Route maps, which depict a path from one location to another, are one of the most common forms of graphic ...