History of Urbanization: Temporal GIS in worldKit

This map of when cities pass the 1 million population barrier, 1775 - 1975 is a demonstration of temporal GIS features currently under development in worldKit.

GIS usually computes along the spatial dimension. Yet many processes and systems investigated with GIS have a significant temporal dimension: urban planning and land use, hydrology, fires, ecological change.

Methods of interaction and presentation in Temporal GIS are still open questions. I'm really curious to see how this works out.