An Application of the Color Space to the Legibility of Maps: For the Uses, Colors

The city is a complex reality of uses that can be analyzed and represented through maps. The difficulty relies on the fact that the same piece of land in a plan view may contain different uses at different heights. This paper presents a method to graphically represent the functional complexity of cities through the colorimetric subtraction. We study the case of Barcelona, where the uses provided by the Catastro are grouped into three categories according to their rhythm: Regular, Variable and Intensive. Each group is assigned a CMY primary color (cyan, magenta, yellow). On the map, each building is represented according to the CMY color corresponding to its use, or according to the resulting color from the mixture of two or three primary colors (red, green, blue or black) if the building hosts several rhythms. The result shows that the distribution of urban rhythms is not homogeneous and varies significantly between urban areas. Intensive (31.5%) and Regular (25.9%) rhythms are the most common in Barcelona. It also makes it possible to differentiate areas of identical urban morphology (Eixample) but with very different activity and life (e.g. Passeig de Gràcia and Poblenou). This method can be applied to other cities as well, making it a useful analysis tool for urban planners, policymakers, and researchers.