PostGIS Raster : Extending PostgreSQL for The Support of ... - CoDE
PostGIS Raster : Extending PostgreSQL for The Support of ... - CoDE
PostGIS Raster : Extending PostgreSQL for The Support of ... - CoDE
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Chapter 1<br />
Introduction<br />
1.1 Context<br />
Our daily life is full <strong>of</strong> situations that require us to make a choice among several alternative<br />
solutions, so-called decision process. For example, we have from simple situations such as shopping,<br />
voting to complicated situations that happen in government and business like resource management,<br />
urban planning and regional planning. But on what do we base to make the best choice ?<br />
Due to the complexity <strong>of</strong> many decisions in government and business that require us to think <strong>of</strong><br />
different elements like stakeholders and categories, it leads to the need <strong>of</strong> using s<strong>of</strong>tware <strong>for</strong> decision<br />
making process. Examples <strong>of</strong> such applications include environmental impact-assessment, geographic<br />
history, population and demographic studies, criminology and military planning.<br />
Among the elements that influence decision making, geographical in<strong>for</strong>mation represents a relevant<br />
source to decision makers. Whether the issue is the location <strong>of</strong> a new public or the development <strong>of</strong><br />
a new project, decision makers should consider such geographic in<strong>for</strong>mation as location, character <strong>of</strong><br />
environment and landscapes.<br />
Furthermore, in the private sectors, a large group <strong>of</strong> companies use geographic in<strong>for</strong>mation as a<br />
tool <strong>for</strong> their locational decision making. <strong>The</strong>se include retail marketing chains (<strong>for</strong> example, Dayton-<br />
Hudson, a major retail firm headquartered in Minneapolis), railroads (<strong>for</strong> example, Southern Pacific<br />
Railroad’s land division), electric power and gas utilities, international import-export firms, transportation<br />
and travel service organizations, publishing firms and real estate planners and investors<br />
[19].<br />
1.2 Goals<br />
Not all sources <strong>of</strong> geographic in<strong>for</strong>mation are reliable. <strong>The</strong> precision <strong>of</strong> geographic in<strong>for</strong>mation can<br />
be influenced indirectly through scholarly publications. <strong>The</strong>se publications tend to influence decision<br />
makers’s understanding about climate issues. So it is important to have a useful tool, such as a<br />
geographic in<strong>for</strong>mation system, that helps user to handle directly geographic in<strong>for</strong>mation and thus<br />
guarantees the correctness <strong>of</strong> in<strong>for</strong>mation.<br />
Most <strong>of</strong> the current geographic in<strong>for</strong>mation systems provide a vector type <strong>for</strong> manipulating geographic<br />
in<strong>for</strong>mation. However, there are very few attempts to support a data type that describes the<br />
distribution <strong>of</strong> physical phenomena that change continuously in time and space, so-called continuous<br />
fields. Example <strong>of</strong> such phenomena are temperature, pressure, precipitation, land elevation, land use,<br />
population density and etc.<br />
<strong>The</strong> main contribution <strong>of</strong> this thesis is to introduce a new data type <strong>PostGIS</strong> <strong>Raster</strong> that supports<br />
continuous fields in <strong>PostgreSQL</strong> database. In addition, it also describes an application that allows<br />
user to exploit the temporal feature <strong>of</strong> geographic data using <strong>PostGIS</strong> <strong>Raster</strong>.<br />
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