Too Many Markers, Revisited: An Empirical Analysis of Web-Based Methods for Overcoming the Problem of Too Many Markers in Zoomable Mapping Applications

The growing amount of available data is creating a need for mass-data visualizations in many areas. The mapping of large spatial data sets is not only of interest for experts anymore but moves into the domain of public applications with regard to the latest advances in web cartography. This creates a need for usable and understandable interactive techniques that allow the visualization and exploration of large spatial data sets. In a series of experiments we look at a variety of technologies aiming at overcoming the obstacle of displaying large spatial datasets in interactive mapping applications. In this short paper we will present our ongoing research on the methods of Marker Clusters, Heat maps and Tiled Heat maps as well as a quantitative and qualitative empirical evaluations of the performance of each of these methods. We conclude with what we think should be a new direction for further research in this area.