INTRODUCTION TO GIS
Almost everything that happens around us encompasses our environment precisely surface and near surface of the Earth. We travel on its surface and lower levels of the atmosphere, and through tunnels below the surface. We mine the Earth, to get at mineral deposits, and drill well to access water, oil or gas. Keeping track and getting information of these activities is important and knowing where it is occurring can be the most convenient basis of tracking. All these and many more such kind of information related to our Earth comes under one head, geographic information.
Simply, stating geographic information obtains meaning from both aspects of data i.e. “where” and “what”. However, exactly it comprises of data about the surface, sub surface and atmosphere of the Earth, its interpretations and explanations applied to those data, and an organizational framework for understanding the information. In general, geographic information is considered in the form of maps, photographs taken from the aircraft, and images collected from satellites, but the concept embraces any type of information, which may be positioned, on or relative to the Earth. It may be acquired through direct measurement, remote sensors, in situ observations; defined through survey or legal description; interpreted from data analysis or simulation.
Computerization has revolutionized the way we communicate, analyze our surroundings, and make decisions. Data representing the real world can be stored and processed so that they can be presented and visualized in vivid manner. This has actually led to profound changes in how we use and understand information about the Earth.
1.2 Understanding GIS
Geographic Information System (GIS) is a computer based information system used to digitally represent and analyze the geographic features present on the Earth' surface and the events that taking place on it. GIS integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. It allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts.
GIS helps us to answer questions and solve problems by looking at our data in a way that is quickly understood and easily shared. GIS technology can be integrated into any enterprise information system framework. To understand GIS properly, let’s look into its component parts of the term separately.
Geographic: The term “Geographic” is used because GIS primarily deals with spatial features. These objects can be referenced or related to a specific location in space. The objects may be physical, cultural or economic in nature. Vivid features on a map are pictorial representations of these spatial objects. Symbols, colors and line styles are used to represent the different spatial features on the two-dimensional map.
Information: The term “Information” here represents the large volume and complex data processing activities, which are usually handled within the GIS software. Conventionally maintained as paper files, computer technology has enabled much more efficient handling and management of information within automated database management systems. System: System can be defined as a group of interacting, interrelated, or interdependent elements forming a complex whole which work together to achieve a common goal. This term is used to represent the systems approach taken by GIS, whereby complex environments are broken down into their components parts for ease of understanding and handling, but are considered to form an integrated whole.
Therefore, we can now define a Geographic Information System as a computer based system which is used to capture, store, query, analyze, and digitally reproduce geospatial data.