Geography Reference
In-Depth Information
in society. The example in Figure 15.1 displays a boat trip (the path) between two harbours
(called stations). At this observation scale stations are equal to no-movement. However,
if one zoomed in on those stations, it is very likely that one would observe movement,
since people meet for activities such as sport or lectures. The time at which people meet at
a station creates 'bundles'. The non-horizontal lines indicate movements. The space-time
path can be projected onto the map, resulting in the path's footprint. Another important
time-geography concept is the notion of the space-time prism. In the cube it occupies the
volume in space and time in which a person can reach in a particular time-interval starting
and returning to the same location (for instance: where can you get to during lunch time, and
still be back on time). The widest extent is called the potential path space and its footprint
is called the potential path area. It can be represented by a circle, assuming it is possible
to reach every location at the edge of the circle. In reality the physical environment (being
urban or rural) will not always allow this due to the nature of, for instance, the road pattern
or traffic intensity; in the case of Figure 15.1's boat trip, the potential path space is limited
to the size of the boat.
When the concept of the space-time cube was introduced, the options for creating the
graphics were limited to manual methods and the user could only experience the single view
created by the draftsperson. A different view of the cube would mean going through the
laborious drawing exercise again. Today software exists that allows the automatic creation
of the cube and its contents from a database. Developments in geovisualization allow one to
link the (different) cube views to other alternative graphics. Based on the latest developments
in geovisualization, this chapter presents an extended interactive and dynamic visualization
environment, in which the user has full flexibility to view, manipulate and query the data
in a space-time cube, while being linked to other views on the data. The aim is to have
a graphic environment that allows creativity via an alternative perspective on the data to
inspire the mind with new ideas and to solve particular geo-problems.
15.4 The space-time cube at work
In this section several traditional and non-traditional space-time cube applications will
be discussed. For all cases it is assumed that a better (visual) exploration and understand-
ing of temporal events is possible in the environment presented. Prominent keywords are
interaction, dynamics and alternative views which each have their impact on the viewing
environment proposed. Interaction is needed because the three-dimensional cube has to
be manipulated in space to find the best possible view, and it should be possible to query
the cube's content. Time, always present in the space-time cube, automatically introduces
dynamics. The alternative graphics appear outside the cube and are dynamically linked. The
combination should stimulate thinking and potentially lead to new insights and explana-
tions. However, the question if this indeed works will be discussed in the last section of this
chapter.
The available functionality can be distinguished in display and query functions and
in viewing functions. The first include the options to switch content on or off, change
content appearance and query display objects. The second include options to manipulate
the cube in three-dimensional space (rotate and translate) and the possibility to zoom in
and out. As a special function one can move the base map (by default at the bottom of
the cube) along the time axis. This allows one to 'follow' the space-time path and keep
Search WWH ::
Custom Search