This visualization shows the development of the crowd density during the 2011 Lord Mayor's Show in London. The "hotter" (i.e. red) the blobs are, the denser the crowd was at that location.
The data has been gathered by a smartphone application collecting live sensor data from users. It has been developed by Tobias Franke of the University of Passau's Embedded System Lab.
The heatmap and the corresponding visualization have been realized by Martin Wirtz of the ETH Zurich's Wearable Computing Lab.
Prof. Eve Mitleton-Kelly (director of the Complexity Group at the London School of Economics) was involved in the development as policy maker.
The overall system allows emergency services to gain an almost-live insight into the crowd density at large scale events. The software has been developed as a part of the Socionical research project (for more information see http://www.socionical.eu).