Selected Publications

In this paper we examine the concept of staged analysis through a case study on visualizing urban mobility exhibited in a public gallery space. Recently, many cities introduced bike-sharing in order to promote cycling among locals and visitors. We explore how citizens can be guided from evocative impressions of bicycling flows to comparative analysis of three bike-sharing systems. The main aim for visualizations in exhibition contexts is to encourage a shift from temporary interest to deeper insight into a complex phenomenon. To pursue this ambition we introduce cf. city flows, a comparative visualization environment of urban bike mobility designed to help citizens casually analyze three bike-sharing systems in the context of a public exhibition space. Multiple large screens show the space of flows in bike-sharing for three selected world cities: Berlin, London, and New York. Bike journeys are represented in three geospatial visualizations designed to be progressively more analytical, from animated trails to small-multiple glyphs. In this paper, we describe our design concept and process, the exhibition setup, and discuss some of the insights visitors gained while interacting with the visualizations.
VISAP, 2016

A visualization system that allows a diverse group of users to visually explore public transit data on a multi-touch tabletop. It provides multiple perspectives of the data and consists of three visualization modes conveying tempo-spatial patterns as map, time-series, and arc view. We exhibited our system publicly, and evaluated it in a lab study with three distinct user groups: citizens with knowledge of the local environment, experts in the domain of public transport, and non-experts with neither local nor domain knowledge. We discuss the design considerations in developing our system, and describe our lessons learned in designing engaging tabletop visualizations.
AVI, 2014

Visualizing data with geo-spatial properties has become more important and prevalent due to the wide spread dissemination of devices, sensors, databases, and services with references to the physical world. Yet, with existing tools it is often difficult to create interactive geovisualizations tailored for a particular domain or a specific dataset. We present Unfolding, a library for interactive maps and data visualization. Unfolding provides an API for designers to quickly create and customize geovisualizations. In this paper, we describe the design criteria, the development process, and the functionalities of Unfolding. We demonstrate its versatility in use through a collection of examples. Results from a user survey suggests programmers find the library easy to learn and to use.
SouthCHI, 2013

Recent Publications

More Publications

. Visually Analysing Urban Mobility. Journal of Cartography and Geographic Information, 2020.

. cf. city flows. Leonardo, 2020.


. What is happening in the city? A case study for user-centred geovisualisation design. Journal of Location Based Services, 2019.


. Environmental Art as Physicalization Technique. Dagstuhl Reports, 2019.

. Shifted Maps: Revealing spatio-temporal topologies in movement data. IEEE VISAP’18, 2018.

Project Video

. ViaVelox - A System to Visually Analyze GPS-tracked Bike Rides. IEEE VIS Poster, 2018.

PDF Project

. What We Learned Through User-Centred Evaluation of Geovisualizations. CityVis Workshop, 2018.

. WanderVis - Interaktive Visualisierung von Bevölkerungsbewegungen. In Planerin, 2018.



In courses at the Mannheim University of Applied Sciences, data visualizations prototypes on various topics are developed following recent design and research approaches. This page documents the projects designed by the students.


A visualization system for public transit planners and policy makers to better understand and explore passenger demands. Running on large multi-touch tabletop, the system enables experts to investigate how delays and passenger load might affect each other through a zoomable Marey chart.

Via Velox

Visualizing GPS-tracked bike rides to better understand cycling behaviour. The system allows to interactively analyze bicycle traffic by visualizing rides tracked and shared by cyclists through a mobile app.

cf. city flows

A comparative visualization environment of urban bike mobility designed to help citizens casually analyze three bike-sharing systems in the context of a public exhibition space.


I am a teaching the following courses at Mannheim University of Applied Sciences:

  • GDV - Grundlagen der Informationsvisualisierung. Introduction to information visualization.
  • APV - Applied Project Visualization. Advanced project-based course on information visualization.
  • SE2 - Software Engineering 2. Introduction to agile development, user interface, and usability.
  • HDI - Human Data Interaction. Graduate course on natural user interface and data exploration.



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Prof. Dr. Till Nagel
Hochschule Mannheim
Paul-Wittsack-Str 10
D-68163 Mannheim

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Prof. Dr. Till Nagel

Zuständige Aufsichtsbehörde
Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg
Königstraße 46
D-70173 Stuttgart


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