Part I presents the preliminary background of what a GIS is, why it exists,
how it works, and what forms of data it uses. Within this first division, my pri-
mary focus is to get readers up to speed on GIS’s composition and I take an
explicitly less technical path to achieving this. A more technical approach to this
background information would leave the reader swathed in tangential theory
and would needlessly add further complexity to an already intricate subject. The
topics in Part I are supportive in nature and are approached as such with distinct
technical brevity.
Part II is the true “nuts and bolts” of GIS and, as such, is approached with
a much greater technical treatment. My approach to Part II is to comprehen-
sively explain the theory behind GIS’s core components, such as the reference
model of the Earth, the coordinate systems, and the map projection. As you will
notice, Part II is dramatically more complex in nature than Part I and this is
done for a specific reason: Most GIS uncertainty, misgivings, and misuse extend
from a limited understanding of these core components. I believe a comprehen-
sive understanding of these topics is essential for effective, proper, and creative
GIS use.
Part III takes a step beyond the theoretical to provide an overview of geo-
graphic data presentation, real-world applications, and inexpensive (practice)
systems and data. To this end, Part III is technically less complex than the previ-
ous part for the sole reason of conveying a clearer vision of how GISs are actually
used, rather than overwhelming the reader with a thorough discussion on each
element.
I want to highlight one other featurea benefitto my approach: It is
theory based rather than hands-on based. I call it a benefit because true
hands-on approaches lead the reader to focus primarily on the use of a GIS (typ-
ically on a specific system) rather than on understanding a GIS. Presented too
early, this hands-on method, I feel, becomes an impediment to comprehension.
A quality theoretical understanding is the key ingredient to effective and insight-
ful real-world use. A hands-on approach restrictively focuses on a particular sys-
tem, while a theory-based approach lets the user (reader) freely experiment and
choose the system on which to learn. This is not to say a hands-on approach to
GIS is a wrong learning method; I am simply stating that for the best use of a
GIS and to gain the greatest amount of user perspective, the theory-based
approach proves beneficial and leaves the reader at the doorstep of hands-on
practice.
I hope you enjoy this book and gain a deep appreciation and excitement
for geographic information systems.
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Geographic Information Systems Demystified