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Geographic Information System- An overview
What can one do using GIS?
It's been said that better information leads to better decisions, however in order to get that information you need to be able to ask the right questions, and in order to ask the right questions you need the right set of tools. Almost all of the questions and issues we are faced with have a geographical component to them. Questions such as where, when, how, why, what if all have an obvious or hidden geographical component. Therefore a GIS with its ability to link and display different data sets on the basis of a common geography appears to be the perfect set of tools for supporting a decision making process, but that's not the end of the story. It is a very well known fact that when we finally succeed in answering one question, a hundred new ones suddenly come to mind, remember maps are food for thought. The real power of a GIS lies in its analytical capabilities to provide simple solutions to complex questions to become a better-informed individual capable of making better decisions. Query and Display One can start your GIS odyssey using simple queries such as show the states of India in different ranges of literacy rate and he can the see the map (Fig. 4).  Fig. 4: Literacy Map of India Buffer analysis This help to answer spatial relationship type of questions like how much area is likely to be submerged in case of any dam brust or how much area can get flooded if the water level of a particular river rises 1m above danger mark. Ex. Show me the villages in my district which have access to a medical facility within 8 km from the village (Fig. 5). Network Analysis Network operators provide a way of solving network and transportation related questions. It is helpful in finding the shortest routes, alternative routes, pollution free routes and so on which are very important in case of accidents, disasters etc.  Fig. 5: Medical facility reaching 8 KM radius (Villages Benefited) Overlay Analysis and Terrain Modeling Our forester friend has in some ways has a need to know where the trees are, but logging trees will have an impact on the ground and the landscape, depending on the type of soils and the slope of the land different patterns of soils erosion may take place, which will impact the local water supply in different ways. The forester will have to evaluate his decision on which trees to cut down not having any drastic impact on the environment.  Fig. 6: Digital Elevation Model Overlay analysis and terrain modeling are methods used by GIS to answer these types of questions by allowing us to look for areas of overlap, e.g. areas where you own a strand of trees that grow on a particular type of soil, or view the terrain assessing the effects of erosion given the slope of the land, or the visual impact clear cutting will have on the landscape. There are virtually no limits to the scope of GIS analysis by combining any of the modes of analysis and query tools provided by a GIS you can derive answers to the most complex questions posed by any activity or field of study. |