Geography Reference
In-Depth Information
erenced data for addressing planning and management problems. In addi-
tion to these technical components, a complete GIS must also include a
focus on people, organizations, and standards (
distribution/naturalresources/components/DD6097ag.html ).
This definition merges parts of the first and second definitions specify-
ing purposes and the importance of “people, organizations, and standards.”
It starts out with the components of Duecker's and Kjerne's definition, add-
ing more specific purposes and rationales and notes the importance of non-
technical elements.
Definitions like these provide more substance for people unfamiliar
with GIS, but very interested in using GIS in their organizations. In this defi-
nition one of the purposes is “management problems.” It also broadens the
consideration: this is not just a matter of technology. The people working on
the problems, the organizations, and the standards used in developing the
GIS must also be considered.
One thing these definitions fail to cover is that “layers” are a common
term for describing the organization of data in a GIS. The “layer” organiza-
tion is very significant. It allows for the storage of multiple geographic repre-
sentations of the things and events in the same GIS. If they use the same
coordinate system, they can even be combined. This concept underlies the
MPLIS and SDI concepts, even if the combination of two “layers” can lead to
many problems because of differences in geographic representation, often
detected as problems with accuracy. “Layers” are the visual concept; in data-
bases the data can be stored in various formats. The term “layers” helps peo-
ple imaging the potential relationships and combinations of different geo-
graphic representations.
Example GIS Applications
Out of the plethora of GIS applications, this section presents a few vignettes
that are illustrate the roles of geographic representation and cartographic
representation and the significance of accuracy, goals, and conventions in
developing GIS applications.
Environment and Conservation Applications
In Japan a GIS application was developed to store and manage three-dimen-
sional surface and subsurface data in Akita, Yamagata, and Kanagaw prefec-
tures. The application allows users to construct f lexible analysis and exam-
ine the effects of preventative structures and plantings, and it can actually
simulate landslide movements. Its geographic representation takes various
hydrogeological characteristics into account, which can be linked to topo-
graphic maps, technical drawings, and orthorectified photos. Organized into
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