Abstract:
A major difficulty in the analysis of disaggregate activity-travel behavior in the past
arises from the many interacting dimensions involved (e.g. location, timing, duration and
sequencing of trips and activities). Often, the researcher is forced to decompose
activity-travel patterns into their component dimensions and focus only on one or two
dimensions at a time, or to treat them as a multidimensional whole using multivariate
methods to derive generalized activity-travel patterns. This paper describes several
GIS-based three-dimensional geovisualization methods for dealing with the spatial and
temporal dimensions of human activity-travel patterns at the same time while avoiding
the interpretative complexity of multivariate pattern generalization or recognition methods.
These methods are operationalized using interactive 3D GIS techniques and a travel diary
data set collected in the Portland (Oregon) metropolitan region. The study demonstrates
several advantages in using these methods. First, significance of the temporal dimension
and its interaction with the spatial dimension in structuring the daily space-time
trajectories of individuals can be clearly revealed. Second, they are effective tools
for the exploratory analysis of activity diary data that can lead to more focused analysis
in later stages of a study. They can also help the formulation of more realistic computational
or behavioral travel models.