What is GIS?. A technology hardware & software tools An information handling strategy The objective: to improve overall decision making. GIS: a formal definition.
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“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”
“… a special case of information system where the database consists of observation son spatially distributed features, activities or events, which are definable in space as points, lines or area. A geographic information systems manipulates data about these points, lines and areas to retrieve data for ad hoc queries and analyses”
Water pumpGIS concepts are not new!
Data Base Management SystemGIS: historical background
This technology has developed from:
Cross-disciplinary nature of GIS
G I S
Computer hardware / software tools
Specific applications / decision making objectives
Latitude / Longitude
Distance & bearing
Feature : Building
Name : Next
Address: 5 Market Place
Owner: Ms J Shore
Tel. No: 0181 547 1245
Floor space 1300 sq m
as geometric objects:
points, lines, polygons
as image files
composed of grid-cells
1 1 20 50
1 2 24 45
1 3 52 55
2 1 0 45 46 40
0 0 0 0 0 0 0 2 0 0 0 0 0 0 1 0 0 0 0 2 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 2 2 2 0 1 ...Modelling the real world
Land use parcels
A chemical leaked into a river?
The Green Belt exist in relation to the City?
Population changed over the last ten years?
Car ownership in our area?
Linked database table
SQL Query Manager
In the context of GIS, analysis is...“Deriving new information from existing data”
It is also the manipulation of data to solve a problem
e.g. identify all areas within 500m of a lake
Increasing use is made of the analytical capabilities of GIS, BUT
many GIS projects only use the software to store and manage
Yet analysis often relies on many simple basic GIS techniques
and many more . . .