GSI

Geographic information systems (GIS) (also known as Geospatial information systems) are computer software and hardware systems that enable users to capture, store, analyse and manage spatialially referenced data
GISs have transformed the way spatial (geographic) data, relationships and patterns in the world are able to be interactively queried, processed, analysed, mapped, modelled, visualised, and displayed for an increasingly large range of users, for a multitude of purpose.

Introduction:

Geographic Information System (GIS) is a computer based information system used to digitally represent and analyse the geographic features present on the Earth' surface and the events (non-spatial attributes linked to the geography under study) that taking place on it. The meaning to represent digitally is to convert analog (smooth line) into a digital form. "Every object present on the Earth can be geo-referenced", is the fundamental key of associating any database to GIS. Here, term 'database' is a collection of information about things and their relationship to each other, and 'geo-referencing' refers to the location of a layer or coverage in space defined by the co-ordinate referencing system. Work on GIS began in late 1950s, but first GIS software came only in late 1970s from the lab of the ESRI. Canada was the pioneer in the development of GIS as a result of innovations dating back to early 1960s. Much of the credit for the early development of GIS goes to Roger Tomilson. Evolution of GIS has transformed and revolutionized the ways in which planners, engineers, managers etc. conduct the database management and analysis.

A typical GIS can be understood by the help of various definitions given below:-
A geographic information system (GIS) is a computer-based tool for mapping and analyzing things that exist and events that happen on Earth
Burrough in 1986 defined GIS as, "Set of tools for collecting, storing, retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes"
Arnoff in 1989 defines GIS as, "a computer based system that provides four sets of capabilities to handle geo-referenced data :
· data input
· data management (data storage and retrieval)
· manipulation and analysis
· data output. "
Hence GIS is looked upon as a tool to assist in decision-making and management of attributes that needs to be analysed spatially.
Need of GIS:

Many professionals, such as foresters, urban planners, and geologists, have recognized the importance of spatial dimensions in organising & analysing information. Whether a discipline is concerned with the very practical aspects of business, or is concerned with purely academic research, geographic information system can introduce a perspective, which can provide valuable insights as
70% of the information has geographic location as it's denominator making spatial analysis an essential tool.
Ability to assimilate divergent sources of data both spatial and non-spatial (attribute data).
Visualization Impact
Analytical Capability
Sharing of Information
Factors Aiding the rise of GIS:
Revolution in Information Technology.
· Computer Technology.
· Remote Sensing.
· Global Positioning System.
Communication Technology.
Rapidly declining cost of Computer Hardware, and at the same time, exponential growth of operational speed of computers.
Enhanced functionality of software and their user-friendliness.
Visualizing impact of GIS corroborating the Chinese proverb "a picture is worth a thousand words."
Geographical feature and data describing it are part of our everyday lives & most of our everyday decisions are influenced by some facet of Geography.
Major areas of application:
Different streams of planningUrban planning, housing, transportation planning architectural conservation, urban design, landscape.
Street Network Based ApplicationIt is an addressed matched application, vehicle routing and scheduling: location and site selection and disaster planning.
Natural Resource Based ApplicationManagement and environmental impact analysis of wild and scenic recreational resources, flood plain, wetlands, acquifers, forests, and wildlife.
View Shed AnalysisHazardous or toxic factories siting and ground water modelling. Wild life habitat study and migrational route planning.
Land Parcel BasedZoning, sub-division plans review, land acquisition, environment impact analysis, nature quality management and maintenance etc.
Facilities ManagementCan locate underground pipes and cables for maintenance, planning, tracking energy use.