Role of GIS
Location science and geographic information systems (GIS) have evolved almost independently. There are four
reasons for this. First, early models in location science were simple and
structured as geometric problems (such as those of Weber and/or Fermet).
Second,
many location science models incorporate elements of operations research (OR).
This field entails modeling for decision making, with techniques applicable in
both spatial and non-spatial domains. Since the 1940s, the field of OR has
evolved, and many of the models discussed in this text are solved using
OR-based techniques. Third,
the field of GIS developed not to support location science, but rather to
support a wide range of uses and services. Geographical information systems(GIS) were created to collect, manage, manipulate, display, and analyze spatial
data. Such
systems are intended to present spatial data in the form of a map (e.g., a
thematic map) and to retrieve data in a format suitable for analysis. As a result,
GIS was created to support a wide range of needs, from mapping to spatial
queries, and from visualizing a terrain to supplying data to models and
statistical tools. That is, the goals of developing GIS go beyond the specific
needs of location science because the application domain is much broader.
Finally,
the number of professionals working in both fields has been relatively small,
and work in one has been somewhat independent of work in the other until
recently.
Spatial planning problems
Certain issues addressed in
location science are actually spatial planning problems that can be solved in
GIS without knowledge of operations research or location science. Furthermore,
certain issues in location science can be addressed within a theoretical
framework that does not involve actual data or specific operations research
techniques. Many location problems, from retail store siting to biological
reserve site design, involve the need to characterize an application domain
complete with spatial data of considerable detail (e.g., road network, census
tracts, population estimates, and so on), and rely on a combination of
functionality, ranging from GIS to models and algorithms based on operations
research.
Location modeling
As problem-solving applications
become more sophisticated, the spatial data required in their applications must
be supported in some way by GIS. As a result, the role of GIS in location
modeling ranges from central to peripheral data support, recognizing the need
for complex spatial manipulation, query, and computation. For example,
locating cell-phone towers necessitates characterizing the terrain as well as
surface clutter, which are elements that reflect, bend, or obscure cell-phone
signals (e.g., buildings and vegetation).
Uses of GIS examples
Many GIS packages include
terrain modeling, and keeping track of ground cover via data attributes aids in
estimating clutter height. As a result, GIS keeps track of the information
required to estimate the area coverage of a potential cell-phone site. Simply
put, an antenna reception model can be easily integrated with a GIS data model
to generate map coverages of potential sites, whereas such a model would
necessitate extensive database development and data collection without the use
of a general purpose GIS.
What we tried to show is that
as these three modeling areas (GIS, OR, and location science) matured, there is
a convergence and burgeoning overlap between these fields based on the demand
for better and more accurate spatial data, the demand for better models
characterizing real landscape problem domains, and the demand for better models
characterizing real landscape problem domains, and the need to map and
visualize solutions to support decision making at a variety of scales, ranging
from the warehouse floor to harvest areas in a large forest plantation to the
infrastructure of pipes and pumps, reservoirs, and tanks in a water supply
system. Whether
it's a water tower or a retail store, future applications are likely to be
inextricably linked with GIS, relying on a wealth of spatial data and spatial
operations and utilizing models that characterize the problem domain as
accurately as possible. This
is the future of not only business location decisions, but also location
science applications in general. Looking beyond theoretical location constructs
and focusing on actual siting problems will result in the development of new
models, data structures, algorithms, and theoretical principles.
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