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Geographical Information System

Published on January 2019 | Categories: Documents | Downloads: 11 | Comments: 0



Geographical information system To answer apparently simple geographic question like. •

What is the population of particular city? What are the characteristic of soil in the particular land? There are any trend in the patterns of earth quake in India which could help predict future quake? • •

Hows the distribution of urban and rural population changed between past times? this all requires proper and accurate data derives from several source. •

The art, science, engg and technology required to answer these geographical question is called geographical information system. Roger tomlin the father of Canada GIS, saw that if  map could be represented in digital form, then it would be easy to make measurements of its basic component, specifically the areas assigned and typical hand measurement of area. So once information of any kind is in digital form, it is much easier to manipulate, copy, edit and format.

The world as composed of largely independent layers and spatial element. Each layer and spatial data representing some component of environment. This layers includes ground water, natural vegetation, soil and other resources. Although the initial data was strictly manual.

Roots of GIS •

GIS has its roots provided by the development of  remote sensing. In the late 60s ,as a potentially cheap and effective source of earth observation. While many of the techniques for processing remote sensing data are highly specialized So more general GIS techniques become important in order to combine information derived from remote sensing with other collateral information

Today many GIS include extensive functionality for image processing and all types of remote sensing we increasing primary data source. Today, the term GIS tends to be applied whenever geographical information in the digital form is manipulated , whatever be the purpose of that manipulation, using a computer to make a map is referred to GIS.

GIS might provide the medium for studying one or more fundamental issues that arise in using digital information technology to examine the surface of the earth or any related systems. GIS is a computerized database system for capture, storage, retrieval, analysis and display of spatial data. It is a general purpose technology for handling geographic data in digital form, and for satisfying the following specific needs among others.

The ability to preprocess data from large stores into a form suitable for analysis, including operations such as reformations, change of projection, resampling. Direct support for analysis and modeling. Post processing of results including such operations such as reformatting and mapping.

The four Ms •

There are mainly for key activities that any urban planners or scientists or resource managers use geographic information, They observe and measure environmental parameters and develop map which portray characteristics of earth.

This four activities are measurement, mapping, monitoring and modeling termed as key activities which can be enhanced by using information technology through GIS measurement


Land use/ land cover Agricultural hydrology

Environmental assessment Drainage network




GIS technology is more different traditional mapping and map analysis.


GIS is based on the mathematical framework of primitive map analysis It provides a foundation for advanced analytic operations involving spatial analysis and measurement. Another major function of GIS capability is the study of environmental surroundings and the monitoring of environmental parameters.

Contribution discipline/branch •

GIS has been called “ enabling technology” because of the potential it offers for the wide variety of disciplines dealing with spatial data.

Figure shows the variety of disciplines which deals with the spatial data cartography


geography CAD Computer soft.

 Automated cartography

GIS statistics

surveying photogramm etry Digital photogrammetry Remote sensing technology

Geography – is broadly concerned with understanding the world and man’s place in it.

It provides technique for conducting spatial analysis. •

Cartography- it concerned with display of  spatial information.

It is now the main source of input data for GIS(maps) and has a long tradition in the design of maps which is an important form of  output from GIS.

Remote sensing- is becoming an important source of geographical data by providing digital images derived from space and air. Remote sensing provides techniques for data acquisition and processing anywhere on the globe at the low cost, and have consistent update potential while integrated with GIS. Remotely sensed imagery can be immerged with other data in a GIS providing real-time spatial analysis.

Surveying and photogrammetry - provides data of positions of cadastral objects like land parcel and building, and topography. Aerial photogrammetry – deals with the photographs taken by the aerial cameras. Aerial photography is one of the most powerful data capturing technique for the creation of GIS spatial database Related data can be extracted from the aerial photography and can be useful as a input for a GIS. •

Computer assisted design(CAD)- provides software , techniques for data input, display and visualization. DBMS contributes method for representing data in digital form. Mathematics – several branches of math's, especially geometry and graph theory are used in GIS system design and analysis of  spatial data. Statistics – used to build models and perform spatial data. •

Availability of large quantities of spatial data in the form of digital aerial photograph, digital remote sensing imagery, advancement of  computer hardware, software and software development increasing demand of spatial information for management, and infrastructure development parameters, lead to have a system to handle all these requirement. In order to handle such data to meet these demands, to store, retrieve, handle, analysis, manipulate and display the results, it requires computer based system is GIS.

definition •

GIS are decision support computer based system for collecting, storing, presenting and analysing geographic spatial information. GIS is much more advanced than computer added design or any other spatial data system.

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