15.4.10.2. GIS (GEOGRAPHICAL INFORMATION SYSTEM)

GIS can be defined as ‘a configuration of computer hardware and software specially designed for the acquisition, maintenance and use of cartographic data’.

A GIS, or Geographic Information System, is essentially a system that allows us to capture, analyze, and present spatial data. It combines hardware (like computers and GPS devices) and software (programs that analyze data) to manage geographical information. This system can be used for both mapping and analysis, making it a powerful tool for many applications, especially in environmental management.

Think of GIS as a high-tech map that doesn't just show roads and landmarks but can also provide data about the environment, like where certain plants grow, where pollution is located, or how urban areas are expanding over time.

GIS can store large multidisciplinary datasets, identify complex interrelationships between environmental characteristics, evaluate changes over time, and serve as a dataset for various mathematical models.

One of the key capabilities of GIS is its ability to handle large amounts of data from different disciplines. It can analyze how different environmental factors relate to one another, such as how changes in land use impact water quality. This capability allows for comprehensive assessments over time, helping researchers and planners make informed decisions based on data trends.

Imagine using a GIS like a detective's toolkit. By piecing together various clues (data points), such as air quality records, population growth patterns, and geographical layouts, we can uncover complex relationships and solve environmental mysteries.

GIS is used for site impact prediction (SIP), wider area prediction (WAP), cumulative effect analysis (CEA), and generating trend analysis within an environment.

In Environmental Impact Assessment (EIA), GIS provides critical analytical capabilities. It helps predict how a new project (like a road or factory) will impact local environments, allowing planners to assess potential effects before construction begins. This foresight can guide decision-making to minimize negative outcomes.

Consider a new highway project. Before construction, planners use GIS to predict how the highway might affect local wildlife, air quality, or water sources. This predictive power is like looking into a crystal ball, helping them understand possibilities before making any commitments.

Erickson (1994) suggested four ways of using GIS for EIA: Overlay method, Checklist method, Matrix method, and Network method.

Different methods can be employed to utilize GIS in Environmental Impact Assessments. The overlay method combines different datasets to analyze interactions between them; the checklist method groups environmental factors; the matrix method relates project activities to their impacts; and the network method shows how various impacts are interconnected. Each method serves to clarify environmental assessments and facilitate analysis.

Using GIS for EIA might be compared to creating a recipe. The overlay method is like placing various ingredients (data layers) on top of each other to see how they interact, while the checklist is like laying out all items required for the recipe to ensure nothing is missed during preparation.

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