SOMViz: Web-based Self-Organizing Maps

The self-organizing map (SOM) method has become popular in various disciplines for visual exploration of large, complex, multivariate databases. Despite the increasing popularity of this powerful, but computationally intensive, neural network approach, web applications involving SOM construction and visualization are still rare. We introduce SOMViz, a simple, interactive, web-based prototype system, accessible online through a simple graphical user interface, allowing users without programming knowledge to generate SOMs from multivariate geographic datasets, and visually explore them in combination with thematic maps. At the heart of our contribution lies a proof-of-concept based on an open architecture, including open source technology. We first outline and evaluate design decisions of the proof-of-concept system already completed in 2009 in the context of current state-of-the-art web technology, and then present implementation details and respective functionality of the SOMViz prototype applied to a case study with Swiss population census data as an example. With this contribution, we hope on the one hand to facilitate access to the powerful SOM analysis method for non-specialists, based on generic and open web technology. On the other hand, we offer this solution as a starting point to apply long-standing cartographic design principles and approaches to emerging non-geographic mapping technologies and methods.