Our TimeEdgeTrees tool allows us to explore dynamic quantitative data in tree diagrams by interactive data filtering
and zooming. The spatial proximity of neighboring hierarchically structured elements allows us to easily
explore trends, countertrends, periodicity, temporal shifts, or anomalies during the evolution synchronously.
Interactive features such as expanding or collapsing of subhierarchies additionally help to detect the aforementioned
phenomena on different levels of granularity. The usefulness of our visualization technique is
illustrated by water level data acquired at more than 450 measurement stations along German rivers for 768
points in time.