Geography Reference
In-Depth Information
1
Introduction
Spatial data analysis
1.1
Geographical or spatial data play a vital role in many parts of daily life. Either directly,
as in the use of a map for navigating around a city, or indirectly, where we use resources
like water or gas, we are dependent on information about where things are located
and about the attributes of those things. Making use of spatial data requires a whole
set of approaches to extract information from those data and make them useful.
Geographical information systems (GIS) play a key role in this context. GIS provide a
means of generating, modifying, managing, analysing, and visualizing spatial data.
h e key contribution of GIS, above and beyond functions provided by other forms of
sot ware such as cartographic mapping or computer-aided design packages, is in the
analysis of spatial data. Broadly, analysis is concerned with breaking apart a problem
with the aim of i nding a solution to this problem. In terms of this topic, the aim is to
introduce some ideas and methods that may be useful in the analysis of spatial data.
For example, approaches are presented for:
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summarizing a set of values (e.g. what is the mean average of all values?)
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identifying overlaps between dif erent features (e.g. what areas with pollution
above some critical threshold are located in areas that have a population of
greater than a particular size?)
i nding the shortest route between one place and another through a network
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(e.g. a road network)
identifying clustering in point events such as cases of some disease (e.g. where
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are disease incidence rates highest?)
exploring spatial patterning in variables (a variable being a quantity that may
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vary across samples; precipitation amount or elevation, for example, can be
considered variables) (e.g. does the concentration of some pollutant vary
spatially and where are values largest?)
