Geographic Information System- An overview
This chapter intends to present before the readers the basics of Geographical Information System (GIS), Remote Sensing (RS) and Global Positioning System (GPS). We think lot of talk is being made about mapping sciences yet the basics need to be redefined and made simpler so that the benefit of these technologies can move into the grassroots level wherein any person, no matter without technical background can understand theses technologies. If these technologies have to percolate in our day-to-day activities it has to be the common man to appreciate and utilize these innovations. GIS, GPS and RS have a variety of uses right from agriculture, archaeology, environment, geology, health, land information system, military, urban and rural development, transportation, telecommunication, power, water resource, natural and man made disasters, oil and natural gas, banking and insurance, business geographics, mobile mapping to name a few.
Let us understand the basics first
All forms of human activity include and involve a measure of geography. Whether you are a restauranteur looking to open up a fast food centre, a geologist seeking a pot of black gold, a stock broker shopping for new investment opportunities, or a suburbanite on a quest for the nearest video store the problems facing you are the age old questions of geography, where, when and how.
We all possess a certain understanding of our immediate surroundings, i.e. our neighborhoods and communities through a natural sense of place, however as we increase the scale of our vision to a local, national or international scope our knowledge and therefore our ability to relate things decreases significantly.
What is GIS?
GIS is an acronym for:
Geographic
This term is used because GIS tend to deal primarily with `geographic' or `spatial' or 'graphical' features. These objects can be referenced or related to a specific location in space. The objects may be physical, cultural or economic in nature. Features on a map for instance are pictorial representations of spatial objects in the real world. Symbols, colors and line styles are used to represent the different spatial features on the two-dimensional map.
Computer technology has been able to assist in this mapping process through the development of automated cartography (map making) and computer aided design (CAD). Computer programs can now accomplish in minutes and hours tasks, which previously took days or weeks for cartographers and draughtsman to complete.
Information
This represents the large volumes of data, which are usually handled within a GIS. Every graphical object has their particular set of data, which cannot be represented in full details in the map. So all these data have to be associated with corresponding spatial object so that the map can become intelligent. When these data are associated with respective graphical feature these data get turned to information that is now by click of a mouse on any object its corresponding data get highlighted. All information is data but all data are not information.
Systems
This term is used to represent the systems approach taken by GIS, whereby complex environments are broken down into their component parts for ease of understanding and handling but are considered to form an integrated whole. Computer technology has aided and even necessitated this approach so that most information systems are now computer based.
Therefore, 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.
Geographical information systems are not restricted to the conventional view of geography, i.e. that of people and places on the Earth's surface. Hidden geographies lie everywhere and a GIS is the perfect tool to take with you on voyages of discovery. Whether you are exploring the hidden facets of the World Wide Web, the complex geography of a printed circuit, the architecture of a combat aircraft, or want to know where the high tension transmission lines pass or the intricate layout of the testimony in the Starr report, a GIS will help pave the way for the success of the expedition by providing the means of visualizing and exploring these uncharted territories.