Changes are afoot that are transforming the way we traverse and perceive our cities. Visualizations of our personal and collective movements through the city reveal unseen patterns and relations. These Visualizations are aesthetic representations that can turn data streams into interpretable traces. We believe that visualizations can empower citizens to make sense of the invisible layers in their environment and participate in imagining the city of tomorrow. The exhibition Streams and Traces · Mapping the ephemeral city displays a series of visualizations as novel perspectives on the collective, personal, cultural, emotional, and physical aspects of urban mobility.
In the transport sector, we witness the rise of the sharing economy and the renaissance of walking and bicycling. People are starting to diversify their mobility mix and are seeking more flexible, affordable, and sustainable transport options. A critical component of this development is the smartphone enabling trip planning across multiple modalities on the go. While such services may be logging our every step, stop, and turn, we are still willing to use them to improve our mobility. Similar changes are occurring in many sectors of public and personal life.
Apps, maps, and visualizations open up diverse modes of access to the city, and thus present new perspectives on the multifaceted dynamics unfolding in cities every day. Visualization has left the ivory tower of academia and is gradually evolving into a lingua franca in a seemingly data-rich world. Journalists, planners, and artists turn to visualization to explain, manage, and subvert the transformation of our cities. Previously unseen layers of cities are getting uncovered.
While the changes in transportation have obvious manifestations in the cityscape — pedestrianized intersections, dedicated bike lanes, parking spaces for car sharing — the changes in visual representation are more subtle yet equally fundamental. It becomes possible to see spatial and temporal patterns in our mobility, culture, and communication. The city was always much more than its built form; by visualizing urban data we are now exploring novel methods to reveal these ephemeral and latent aspects of the city. Wurman’s ambition to make the city observable expands 1 way beyond infrastructure and is now addressed through a wide variety of services and initiatives.
As visualization moves out of the neat world of research into the messy world of urban issues, multidimensional data relate to multilayered problems involving diverse stakeholders. Finding the right visualization for a given task or data type increasingly means doing justice to a complex constellation of actors. A helpful and often-used term for this condition is complexity. However, not so much in the sense of last-century cybernetics 2 that aimed at capturing and controlling technical and social systems but rather in the sense of recognizing the richness and depth of comprehensive and dynamic phenomena such as cities. Any demands for objectivity, completeness, or even control are illusory. Instead of making false promises, the complexity of our cities requires a plurality of viewpoints.
To do justice to the complexity of the social-material world of the city we need to develop visualization methods that do not aim at reducing or regulating complexity, but at iteratively approaching and apprehending it. Since data visualizations are increasingly used as the basis for decision-making, we have to be conscious about their power. 3 Data and visualization increasingly lend credence to arguments and struggles. With the increase in visualizations of urban phenomena the meanings of visual and political representation starts to converge.
We might think of the design of visualizations as the rhetoric of data. In that sense, visualization is not just science and technology striving for the best representation, but also the art and skill of speaking to current issues and relevant developments. The design decisions going into a visualization have considerable influence on the perception and interpretation of the visualized data. If we see the thin line between virtue and vice in rhetoric, we should also acknowledge the possibilities and risks in visualization. The deliberate choice of stylistic and functional elements can narrow or expand the reading of an issue. 4 To broaden people’s perspective and challenge their assumptions, a personal engagement with the phenomenon is required. Just as it is difficult to meaningfully speak about anything without positioning oneself, it is arguably impossible to create a meaningful visualization of an issue without taking a stance. If we are interested in the potential of visualization to reveal the complexity of our cities, we also have to grapple with the implicit subjectivities and rhetorics of data and visualization.
To explore the rhetoric of data, the city poses the perfect environment. On the one hand, the city is the place where global challenges have both their likely roots and possible solutions. On the other hand, the urban scale can also serve as an experienceable and graspable granularity of society. Especially, with the decreasing relevance of the nation state, it is cities that grow in economical, political, and cultural importance. As an object of study, the city is also a highly intriguing imbrication of material and social aspects. While the material surface of the city changes relatively slowly, new services radically change our mode of access to the city. 5 The ways we move, meet, work, live, and love are being disrupted, which in itself is a very urban phenomenon. These changes are not only encouraged by mobile services or technologies, but are also subject to the deliberate efforts of individuals and communities to experiment with alternative social practices and structures.
The engagement with these urban developments leads to substantial challenges and opportunities for visualization design and research. With the longstanding aim to devise methods for revealing patterns in data, the focus of visualization research has been mostly on representation and interaction. However, increasingly questions of interpretation and transformation come into play.
Visualizations of urban data are both images and interfaces. As images, they allow us to see invisible streams, traces, layers and patterns thus shaping our general idea of the city. As interfaces, they allow us to reflect and act on our individual and our collaborative behaviour. Visualizations can help breaking up the solidified infrastructure of the city and open up new opportunities for making sense of urban complexity.