From Ocean Teacher Library
Geographic Information Systems (GIS)Contents |
Introduction
A Geographic Information System (GIS) is a technology for managing geographic, or spatial, data. It is an integrated set of hardware and software tools used for the capture, storage, analysis and display of geographic data. GIS technology integrates common database operations such as query and statistical analysis with the visualisation and geographic analysis benefits offered by maps and charts.There is no single definition of a GIS. Definitions often focus on specific areas and disciplines and the context in which it is used. All definitions recognise the spatial component of the data. Some of the broadly accepted definitions of GIS include:
“a geographic information system is a special case of information systems where the database consists of observations on spatially distributed features, activities or events, which are definable in space as points, lines, or areas. A geographic information system manipulates data about these points, lines, and areas to retrieve data for ad hoc queries and analyses“[1]
“a powerful set of tools for the storing and retrieving at will, transforming and displaying spatial data from the
real world for a particular set of purposes“[2]
Some recent definitions include [3]:
- a container of maps in digital form
- a computerized tool for solving geographic problems
- a spatial decision support system
- a tool for performing operations on geographic data that are too tedious or expensive or inaccurate if performed by hand
A more comprehensive and easy way to define a GIS is to look at the nature of the system and how it works with thematic layers. A GIS organises and stores information about the real world as a collection of thematic layers that are linked by geography. This way is possible to analyse the spatial characteristics of the data. A GIS can answer questions about:
- Location: "What is at ...?"
- Trends: "What has happened since ...?"
- Patterns: "What spatial patterns exist ...?"
- Modelling: "What if ...?"
References
- ↑ [Dueker, K. J. (1979), Land resource information systems: a review of fifteen years experience, Geo-Processing, Vol. 1, No. 2, pp. 105-128]
- ↑ [Burrough, P. A. (1986), Principles of Geographical Information Systems for Land Resources Assessment, Oxford: Clarendon Press.]
- ↑ Longley et all (2005) Geographic Information Systems and Science, Second Edition, John Wiley & Sons, ISBN: 0-471-89275-0
Subsections of this Article
| Pagename | Short title | Description | |
|---|---|---|---|
| Components of a Geographic Information System | Components of a Geographic Information System | Components of a GIS | none |
| Fundamentals of Geographic Information Systems | Fundamentals of Geographic Information Systems | Fundamentals of GIS | Provides an introduction to the basic concepts and applications of GIS as a method for analysis of marine data. |
| Geographic Information System Data Models | Geographic Information System Data Models | GIS Data Models | The spatial components of a geographic data can be represented by three data types: points, lines and areas |
| Map Generalization | Map Generalization | Map Generalization | When features are generalised their level of detail is reduced but their overall shape and position is retained |
| Marine Geographic Information Systems | Marine Geographic Information Systems | Marine GIS | Marine GIS is utilized to assist researchers and organizations in achieving research goals related to oceanographic and coastal problems |
| Spatial Analysis | Spatial Analysis | Spatial Analysis | none |
Information about this article
Short title: Geographic Information Systems
Description: A GIS is an integrated set of hardware and software tools used for the capture, storage, analysis and display of geographic data.
Expertise level: beginner
Author: Greg Reed
Approval status: approved
Approved by: Greg Reed
Last change: 2010-5-31
Subsection of: Geospatial Data Concepts
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