Geography Reference
In-Depth Information
2
Key concepts 1
GIS
Introduction
2.1
h is chapter is the i rst of three intended to introduce a set of key concepts that are
central to the approaches described in the rest of the topic. h is chapter focuses
on some key principles of GIS and is followed by chapters on some fundamentals
of statistics and spatial data analysis. h is chapter will briel y discuss ways in which
real-world entities can be represented in a GIS. h e focus will then move on to
methods for spatial data collection, errors, visualization of spatial data, and simple
approaches for extracting information from data sets. More specii cally, the chapter
covers:
•
data and data models, including topology—representing reality in a GIS using
data models and databases
spatial referencing systems and projections—how spatial data are
•
spatially referenced and how parts of the Earth's surface can be represented
on a map
spatial scale—how far spatial properties vary over a given area
•
•
data collection—how spatial data are generated
•
sources of errors in spatial data
•
visualization of spatial data—a key i rst step in any analysis
•
querying spatial data—extracting information from spatial databases.
The following section deals with data models used commonly in GIS.
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