In this article, Kwan and Lee (2004) explore 3D visualisation methods for human movement data. In the language of time-geography, which borrows from early C20th physics, space-time paths describe movements as sets of spacetime coordinates, which (if only two spatial dimensions are considered), can be represented along three spatial dimensions. These concepts have become a fundamental part of recent developments in navigation GIS and other GIScience fields. For instance, Google Maps considers the time at which a journey is planned to more accurately estimate its duration.
While their figures represent a neat set of 3D geovisualisation examples, it might have been worthwhile to have discussed some of the associated challenges and limitations (e.g. obstructed view of certain parts of the data, the potential for misinterpretation when represented on a 2D page, user information overload, the necessity for interactivity etc.). Further, how does 3D visualisation compare with other representations of spacetime paths, such as animation?
More broadly, I didn’t fully understand the claim that time-geography (as conceived in the 1970s) was new in describing an individual’s activities as a sequence occurring in geographic space (i.e. a spacetime trajectory). Time hasn’t been entirely ignored in Geography contexts in the past (e.g. Minard’s map), neither has it been ignored in other disciplines. So does time-geography purely emphasise the importance of the time dimension in GIS research/ software, or does it provide a set of methods and tools that enables its integration into the geographic discipline? Is time-geography done implicitly when researchers include a time dimension in their analysese, or does it represent a distinct approach?
-slumley