This visualization shows the development of the crowd density during the Vienna City Marathon 2012. The "hotter" (i.e. black -> red -> yellow) regions are, the denser the crowd was at that location.
The data has been recorded by a smartphone application collecting live sensor data from users. It has been developed by the Tobias Franke of the Embedded Intelligence Group, DFKI Kaiserslautern  and the Institute for Pervasive Computing, Linz .
The data is being collected in near real-time (delay ~ 1. min) directly from the mobile phones. This allows for an instantaneous heat map visualization. We used the CoenoSense platform  developed by Martin Wirz of the ETH Zurich's Wearable Computing Lab  to collect and data and generate this visualization.
The overall system allows event organizers and emergency services to gain an almost-live insight into the crowd dynamics at large scale events.
The software has been developed as a part of the SOCIONICAL research project .