GIS OVERVIEW

GIS OVERVIEW

Definition of GIS
A system of hardware, software, data, people, organizations and institutional
arrangements for collecting, storing, analysing and disseminating information
about areas of the earth. (Dueker & Kjerne 1989:7-8)
“The organised activity by which people:
- Measure aspects of geographic phenomena and processes
- Represent these measurements, usually in the form of a computer database,
   to emphasize spatial themes, entities and relationships
- Operate upon these representations to produce more measurements and to
   discover new relationships by integrating disparate sources
- Transform these representations to conform to other frameworks of entities
   and relationships” (Chrisman 1997:5)

GIS as an Information System
“An  information system that is designed to work with data referenced by spatial
or geographic coordinates … a GIS is both a database system with specific
capabilities for spatially-referenced data, as well as a set of operations for working
with the data" (Star and Estes, 1990, p. 2)

Disciplines that use GIS
- The number of disciplines using GIS is constantly increasing; owing to:
- Cheaper hardware – the desktop computer
- Cheaper software
- Better training in GIS
- Increased use and awareness of the technology
- The increasing sophistication of GISs
- The Graphical User Interface making them easier to use
- Much inexpensive federal data
- Merge with many parallel technologies

Disciplines Using GIS
- Geology
- Geophysics
- Oceanography
- Agriculture
- Forestry
- Mining
- Environmental science
- Sociology
- Natural Resource Analysis
- Archaeology

GIS Application Areas
- Land use planning
- Locational analysis
- Utility and infrastructure planning
- Real estate analysis
- Marketing and demographic analysis
- Habitiat studies
- Insurance appraisal
- Tax appraisal

Selected applications of GIS
- Primary Industries and Agriculture:
  Irrigation Management, Land Development and Management, Soil Conservation,
  Resource  Management, Forestry Inventory Management, Timber Industry
- Environmental Management:
  Conservation, Flora and Fauna, Wildlife, National Parks, Pollution Control and
  Monitoring, Ecological Modelling
- Disaster Planning:
  Emergency Services, Hazards Monitoring,  modelling flood impacts
- Facilities Management:
  Electricity Utilities, Water Utilities, Gas Utilities, Fire Authorities, Roads Inventory,
  Telecommunications
- Urban GISs:
  Local Government, Urban Planning, Crime Analysis, Cadastral and Land Tax,
  Housing Development
- Marketing Analysis:
  Customers, branches, competitors etc
- Archaeology:
  Locational  analysis, site prediction, site catchment analysis, cultural resource
  management, intra site mapping, etc.

GIS Applications
Application differences in terms of :
- purpose
- themes/types of information
- data model to be used … specific forms of data organisation
- resolution … geographic and temporal scales
- data sources … primary / secondary data
- particular tools …  processing requirements
- etc

GIS development … contributing disciplines
- disciplines that have developed concepts for dealing with space 
- fields that develop geographic data acquisition tools 
- disciplines that provide theories fundamental to our working with space
  and automation
- fields making substantial use of automated spatial information systems
- Geography:… concepts dealing with space
  • geographical analysis, computer cartography, remote sensing
- Surveying: … data acquisition tools
  • geodesy, photogrammetry
- Computer Science: … space and automation
  • computer-aided design, database management, AI/expert systems
- Others
  • Statistics, Mathematics, Civil Engineering