Visual Analysis of Multivariate Movement Data using Interactive Difference Views

The images show kernel density sum of all ship traffic close to Stavanger in a given time period. These plots gives a good quantitative measurement on the volume of traffic in the different areas. If the user investigates how the traffic volume changes over time, however, a side by side presentation will only provide a qualitative idea on changes. Changes (or differences) are made explicit by calculating the difference view and, can be read out in a quantitative manner. In image to the right, the difference view, red indicates higher morning traffic, and blue indicates higher evening traffic. This is an example of a direct difference view, where we have two directly comparable density volumes. Difference Views: