Geography Reference
In-Depth Information
Figure 9.5
Virtual London in Google Earth
user - the concerned citizen for public participation. Initially this was seen as the main focus
for using the model but has had to be restricted due to issues of copyright with the Ordnance
Survey base data used to present this version. The restrictions on data use have been central
to city visualization and GIS in general, especially outside of the academic community. In
short, data costs money to collect and therefore licence to use the data is often restrictive
in terms of further distribution. In terms of Virtual London, this led to the withdrawal of
the public access version, illustrating the difficulty faced by Ordnance Survey in adapting
its licensing policies for the new age (Cross, 2007).
The public face of Virtual London is therefore currently limited to movie files and as
such indirect visualization of data within the city model. While this is restrictive in terms of
public participation and allowing access to the data, it does result in improved visual output
as with movie files one is not concerned with real-time visualization. A good example of this
is how a three-dimensional city model can effectively communicate data in the visualization
of air pollution where such levels of visualization are currently not possible in real time but
possible offline as we show in Figure 9.6.
Figure 9.6 illustrates air pollution data from the Environmental Research Group at Kings
College London, where a pollutant surface based on nitrogen dioxide in three dimensions is
draped over the cityscape. The move to visualize data in three dimensions is controversial and
often seen as mere 'eye candy' by some specialists in the field. Yet in terms of a communication
tool, it illustrates the areas of intense air pollution arguably more effectively than any two-
dimensional map. This may partly be due to the visual nature of the medium allowing a
stronger sense of location and place to be obtained than a top-down two-dimensional view.
As such any amount of data can be visualized with the model. Figure 9.7 illustrates how the
city could flood as a result of sea level rise. With the animation file, it is possible to watch the
water level rise and therefore identify which areas are more at risk according to the degree
of rise. Again, this is a use of the Visual City in offline mode where we can sensibly embed
data to visualize important outcomes.
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