Geographic Information System-2105
Definition of GIS:
Geographic Information System (GIS), an advance and integrative computerized system, denotes a structured
framework designed for assessing, storing, managing, analysing, manipulating, and visualising geographically
referenced data, thereby facilitating the understanding of spatial patterns & trends, processes acting on the
earth surface, relationships, informed decision making, urban and regional planning, environmental
management, natural resource assessment, disaster mitigation, and socio-economic development.
Additionally, GIS combines cartographic techniques [Thematic mapping, symbolization], statistical analysis,
and computational modelling [hardware, software, data] to maximize its functionality.
Peter A. Burrough (1986): A Geographic Information System is a powerful set of tools for collecting, storing,
retrieving, transforming, and displaying spatial data from the real world for a particular set of purposes.
David J. Cowen (1988): GIS is defined as a decision support system involving the integration of spatially
referenced data in a problem-solving environment.
Michael F. Goodchild (1992): A Geographic Information System is a system for capturing, storing, checking,
integrating, manipulating, analyzing, and displaying data that are spatially referenced to the Earth.
Taken collectively, these perspectives reveal that GIS constitutes a comprehensive spatial information and
analytical framework, integrating data acquisition, management, computational techniques, and visualization
tools to facilitate geographic analysis, support informed decision-making, and promote sustainable planning
and resource management within local, regional, and global scales.
Components of GIS:
A Geographic Information System (GIS) functions as an integrated framework for the systematic collection,
storage, analysis, and visualization of spatial and non-spatial data. Generally, its efficiency and analytical
capability depends on five interrelated components: hardware, software, data, people, and methods, which,
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collectively, underpins the effective geographic knowledge and supports decision-making in diverse spatial
and socio-economic contexts.
1. Hardware:
Hardware encompasses the physical instruments and equipment utilized in the operation of GIS. Primarily, it
includes devices for data input, processing, storage, and output. The performance and analytical capacity of
GIS are significantly influenced by the specifications and capabilities of its hardware.
Examples:
• Input devices: GPS receivers, scanners, digitizers
• Processing devices: High-performance computers, servers, workstations
• Output devices: Monitors, printers, plotters
2. Software:
GIS software constitutes the computational tools and applications designed for the management, manipulation,
analysis, and visualization of spatial and attribute data; Software may be categorized as open-source or paid
source.
Examples:
• Open-source software: QGIS, GRASS GIS
• Paid-source software: ArcGIS, MapInfo Professional
3. Data:
Data represents the digital embodiment of real-world spatial phenomena and is the core element of GIS. Data
is, primarily, classified into vector and raster formats, each serving distinct analytical and representational
purposes.
Examples: