1.7. GIS -Contributing Disciplines and Technologies

          

        Geographic information systems is an integrating technology. It evolved by linking a number of discrete technologies into a whole. The development of GIS has relied on innovations made in many different disciplines. As the integrating field, GIS often claims to be the science of spatial information. The contributing disciplines and technologies of GIS are geography, cartography, remote sensing, surveying, photogrammetry, computer science, mathematics, and statistics.

Geography

            Geography is broadly concerned with understanding the world and man's place in it. Geography has a long tradition in spatial analysis and provides techniques for conducting spatial analysis. In fact, all data in a Geographical Information System have some spatial element. GIS is specially designed to handle these spatial data as well as its descriptions.

Cartography

            Cartography is the science and art of designing, composing, and producing maps. It is concerned with the display of spatial information. It has a long tradition in the design of maps which is an important form of output from GIS. Computer cartography, also called "digital cartography" or "automated cartography" provides methods for digital representation and manipulation of cartographic features and methods of visualization.

Remote Sensing

            Remote sensing is the acquisition of information about a phenomenon or object on the Earth's surface without any physical contact. It had played a great part in the development of GIS, as a source of technology as well as a source of data. Remote sensing includes techniques for data acquisition and processing anywhere on the globe at low cost and have a consistent update potential. Interpreted data from a remote sensing system can be merged with other data layers in a GIS

Photogrammetry

            Photogrammetry is the science of obtaining geometric properties about objects on the Earth's surface. It provides high quality data using aerial photographs and techniques for making accurate measurements from them. Photogrammetry is one of the most powerful data capturing techniques used for input in GIS.

Surveying

            Surveying provides high quality data on positions of cadastral objects like land parcel and building, etc. GIS provides a framework for surveying.

Geodesy

            Geodesy is the science of accurately measuring and understanding three fundamental properties of the Earth: its geometric shape, its orientation in space. and its gravity field— as well as the changes of these properties with time. By using GPS, geodesists can monitor the movement of a site 24 hours a day, seven days a week. Geodesy provides source of high accuracy positional control for GIS.

Statistics

            Many models built using GIS are statistical in nature. Many statistical techniques are used in spatial analysis, modelling, and interpolation. Statistics is also important in understanding issues of error and uncertainty in GIS data.

Operations Research

            Operations research is a discipline that deals with the application of advanced analytical methods to help make better decisions. It is often considered to be a sub-field of mathematics. Employing techniques from other mathematical sciences, operations research arrives at optimal or near-optimal solutions to complex decision--making problems.

Computer Science

            Computer Science provides software techniques for data input, display, and representation. Advances in computer graphics provide hardware and software for handling and displaying graphic objects besides techniques of visualization. Database management systems (DBMS) contribute methods for representing data in digital form as well as procedures for handling large volumes of data. Artificial intelligence (Al) enables the computer to act as an “expert” in such functions as designing maps and generalizing map features.

Mathematics

                Several branches of mathematics, especially geometry and graph theory, are used in GIS system design and analysis of spatial data.

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