Geography Reference
In-Depth Information
City is three-fold. First is the ability to view the city in two dimensions via high-resolution
aerial imagery. Levels of detail vary according to location with 'Googleplex' (the Google
Campus) providing the highest current resolution at 2.54 cm per pixel. The use of high-
resolution digital imagery allows the user to gain a visual overview of a city from the air. This
is a new emergence and as such has led to the rise of sites that track locations of sightseeing
within Google Earth. Although the highest resolutions are limited to urban areas, Google
Earth sightseeing is a global phenomenon. To hone this discussion back to the city, the
move to the third dimension has probably the largest impact in terms of visualization of
geographic information than any other. Although predominantly US and Japan based due to
copyright issues on data, which we will return to later in terms of our own model, Google's
three-dimensional cities are fundamental to the idea of the Visual City. They represent
a significant development in the visualization of city environments, not only in terms of
our ability to view building outlines and polygons but also due to their location in true
geographical space. Thus geographical location provides the third issue of importance in
Google Earth, which involves the ability to add data and visualize information using the
three-dimensional Visual City as a backdrop or canvas to other data sources. The ability to
visualize and overlay information opens up a number of applications for the Visual City,
applications which were once in the domain of the professional user, it is these to which we
now turn.
9.3.1 Applications in the visual city
With the rise of computing power has come an increase in publicly accessible GIS information
and with it the ability to visualize in three dimensions, leading to a massive demand for
city models. In terms of Virtual London, the fully functional complete model has been
developed in different ways for different audiences. This is of some importance as each
audience requires a different level of interaction and interface. While the visual use of the
city is almost universally similar between different users, what changes is the level of data
mining possible, the delivery method and the interface. Broadly it is possible to identify
two main categories of use, firstly we have fully professional usage which includes the use
of the model by architects, developers, planners and other professionals who are anxious to
use its full data query and visualization capabilities. For example, an architect might place a
building within the model and use this to assess a variety of issues from its basic visualization
to the impact it might have on traffic and surrounding land use.
In terms of our London model, the fully professional application has been our main focus.
The three-dimensional model has been rolled out to all 33 London boroughs, providing
London with its first city-wide three-dimensional GIS system. This raises a number of issues
in terms of software, hardware and expertise required to manage and view the model. As
such we have rolled out alongside the professional model a customized version written to
dynamically load according to a viewpoint in Google Earth. Figure 9.5 illustrates a section
of the model in Google Earth.
The Google Earth version is specifically developed for the non GIS user. In terms of
professional use, the level of functionality is compromised but the ability to navigate and
overlay other datasets is increased. This is a common trade-off for functionality vs cost
and ease of use. As such the choice to roll out a Google Earth version is important as it
allows any local government employee to view the model. This links in to our second level of
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