Basic GIS Concepts
What is a GIS?
A GIS(Geographic Information System) is any hardware and software systems that enables the users to capture, store, analyze, manage, interpret the geographic features present on the Earth' surface and the events taking place on it.
GIS 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.
Work on GIS began in late 1950s, but first GIS software came only in late 1970s from the lab of the ESRI. Canada was the pioneer in the development of GIS.Much of the credit for the early development of GIS goes to Roger Tomilson. Components of GIS:
GIS constitutes of five key components:
It consists of the computer system on which the GIS software will run. The choice of hardware system range from 300MHz Personal Computers to Super Computers having capability in Tera FLOPS. Software
GIS software provides the functions and tools needed to store, analyze, and display geographic information. GIS softwares that are in use are MapInfo, ARC/Info, AutoCAD Map, etc. The software available can be said to be application specific. When the low cost GIS work is to be carried out desktop MapInfo is the suitable option. If the user intends to carry out extensive analysis on GIS, ARC/Info is the preferred option. Data
Geographic data and related tabular data can be collected in-house or purchased from a commercial data provider. The digital map forms the basic data input for GIS. People
GIS users range from technical specialists who design and maintain the system to those who use it to help them perform their everyday work. The people who use GIS can be broadly classified into two classes. The CAD/GIS operator - whose work is to vectorise the map objects. The GIS engineer/user - whose work is to use the vectorised data to perform query,analysis or any other work. Method
And above all a successful GIS operates according to a well-designed plan and business rules.
MAJOR AREAS OF PRACTICAL APPLICATION
1) Street network-based application:
It is a address matching application used for finding locations at given street addresses,vehicle routing and scheduling, disaster planning,location and site selection, development of evacuation plans and to find an alternative site with exisiting facilities. 2) Natural resource-based application:
management of wild and scenic rivers, recreation resources, floodplains, wetlands, agricultural lands, forests, wildlife. Environmental impact analysis (EIA)
hazardous or toxic facility siting
groundwater modeling and contamination tracking
wildlife habitat analysis, migration routes planning
3) Land parcel-based applicaltion:
zoning, subdivision plan review
land acquisition ,environment impact analysis,
4) Facilities management
Used for locating underground pipes, cables for the maintenance planning and for tracking energy use. 5) GIS in agriculture
GIS is used in a variety of agricultural applications such as managing crop yields, monitoring crop rotation techniques, and projecting soil loss for individual farms or entire agricultural regions.
6) GIS in the environment
GIS is used every day to help protect the environment. As an environmental professional, you can use GIS to produce maps, inventory species, measure environmental impact, or trace pollutants. The environmental applications for GIS are almost endless. 7) GIS in land use planning
People use GIS to help visualize and plan the land use needs of cities, regions, or even national governments. 8) GIS in risk management
A GIS can help with risk management and analysis by showing you which areas will be prone to natural or man-made disasters. Once identified, preventive measures can be developed that deal with the different scenarios.
A raster data type is, in essence, any type of digital...
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