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Geographic Information System

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What is GIS?

Geographic Information System

Firstly and most importantly a GIS is an information system. A system is a group of connected entities and activities which interact for a common purpose. In GIS the common purpose is decision making for managing any spatially distributed activity.

• An information system is a set of processes, executed on raw data to produce information which will be useful in decision making

• A chain of steps leads from observation and collection of data through to analysis

• An information system must have a full range of tools to handle observation, measurement, description, explanation, forecasting and decision making

It is important to remember that GIS can also help to achieve the overall objective of improving the decision making process, whether in an organisation, or within a project.

GIS: a formal definition

The most commonly quoted definition in the UK comes from the Chorley Report “Handling Geographic Information” HMSO, 1987 which is described above.Not everyone agrees with this definition. There are those who believe GIS forms part of  more established disciplines but these definitions tend to ignore the cross disciplinary nature of spatial data.

“A system for capturing, storing, checking, integrating, manipulating, analysing and displaying data which are spatially referenced to the Earth. This is normally considered to involve a spatially referenced computer database and appropriate applications software”

Why is GIS unique?

What distinguishes GIS from other information systems?

• GIS integrates spatial* and other kinds of information within one system: it offers a consistent framework for analysing space

• GIS makes connections between activities based on spatial proximity

• GIS provides the mechanisms for undertaking the manipulation and display of geographic knowledge

*Spatial data will be described in much greater detail in the next lecture.

GIS: historical background

GIS has developed from two independent areas: digital cartography and databases. These developments are closely related to the enormous growth in power, and the corresponding reduction in the cost of computer technology, since the late 1960’s.

Digital cartography

The desire to use computers to replace manual cartographic processes, particularly for the more tedious tasks, was a focus in the 1970’s. Developments in digital cartography often resulted from developments in the larger Computer Aided Design (CAD) field. At the same time the 1960’s quantitative revolution in Geography encouraged the development of computer programs that could undertake map analysis operations that would be difficult or too time-consuming to undertake by hand.

Database links

The use of Data Base Management Systems (DBMS) is very important to the current concept of GIS which involves the integrating of spatial and non-spatial data. The development of relational DBMS was particularly significant with examples such as Oracle being widely used today.

GIS components

The key to establishing this type of technology within an information framework for the purposes of decision making is INTEGRATION: the linking together of technology, data and a decision making strategy. What GIS is all about today is the bringing together of spatial analysis techniques and digital spatial data combined with computer technology. But for many, GIS is much more than a computer database and a set of tools: it is also a philosophy for information management. Often GIS can form the core of the information management within an organisation.There are of course other definitions too. GIS is sometimes referred to as the tool whilst the user may be the Spatial Information Scientist! In recent times the whole subject area has also been referred to as Geographic Information Management (GIM) or even Geomatics

Each of these components will now be examined in further details.

1. Data

2. Software & hardware tools

3. GIS data manipulation & analysis

GIS Applications

Facilities management: Utilities such as electricity, gas, water and cable communication companies all use GIS systems to store, retrieve and analyse their plant and materials. Areas such as customer responses, demand forecasting, fault analysis, network assessment analysis, site planning, strategic planning and market analysis can be generated by the GIS.

Marketing and retailing: these applications tend towards targeting customers and identifying potential markets for customers. The extensive datasets generated from the use of loyalty cards can also be used in conjunction with GIS. Other applications may include: media planning, territory allocation and prospect analysis.

Environmental: Forestry management, impact analysis, resource management, coastal zone mapping, geophysical & geotechnical surveys.

Transport/vehicle routing: this is an example of ‘real-time’ GIS and is used particularly by vehicle routing companies and the emergency services who need to know where there vehicles are located at any given time. Vehicle routing can also be assessed in terms of least cost or efficiency. In addition GIS may also be used for; dispatch, scheduling, franchise planning as well as route planning.

Health: Disease mapping as well as epidemiology, facility planning, provider & purchaser planning, expenditure monitoring and patient analysis can all be carried out using GIS.

Insurance: risk distribution analysis, catastrophe planning, customer service analysis, hazard & prediction analysis and underwriting

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Please note that this is the opinion of the author and is Not Certified by ICAR or any of its authorised agents.