1 Introduction
Following the interactions of physical phenomena over time is an important problem. There have been many papers that deal with time varying phenomena focusing on individual phenomenon or features, examples can be found in the papers [1], [2], [3], [4], [5], [6] and [7]. Today's advanced simulations generate high resolution data at peta-byte or exa-byte scale. As datasets get larger, the number of features in the simulation grows. Similarly, as the resolution becomes finer, some features that appeared large in coarser resolution runs become finer. The change in resolution affects the identification of feature dynamics since some features merge at a lower resolution [9]. This is similar to identifying finer features as a single structure, i.e. group, at a lower resolution. Various interactive navigation and exploration tools proposed to help scientist explore the large scale data at different resolutions as in [9] and [10].