Geographic Information System
Q-1) What is GIS?
A geographic information system (GIS) is a computer system for capturing, storing, checking,
and displaying data related to positions on Earth’s surface. By relating seemingly unrelated data, GIS can help individuals and organizations better understand spatial patterns and relationships.
GIS technology is a crucial part of spatial data infrastructure, which the White House defines as “the technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatial data.”
GIS can use any information that includes location. The location can be expressed in many different ways, such as latitude and longitude, address, or ZIP code.
Many different types of information can be compared and contrasted using GIS. The system can include data about people, such as population, income, or education level. It can include information about the landscape, such as the location of streams, different kinds of vegetation, and different kinds of soil. It can include informatio n about the sites of factories, farms, and schools; or storm drains, roads, and electric power lines.
With GIS technology, people can compare the locations of different things in order to discover how they relate to each other. For example, using GIS, a single map could include sites that produce pollution, such as factories, and sites that are sensitive to pollution, such as wetlands and rivers. Such a map would help people determine where water supplies are most at risk.
Q-2) What can we do with GIS?
GIS can be used as tool in both problem solving and decision making processes, as well as for visualization of data in a spatial environment. Geospatial data can be analyzed to determine (1) the location of features and relationships to other features, (2) where the most and/or least of some feature exists, (3) the density of features in a given space, (4) what is happening inside an area of interest (AOI), (5) what is happening nearby some feature or phenomenon, and (6) and how a specific area has changed over time (and in what way).
1. Mapping where things are. We can map the spatial location of real-world features and visualize the spatial relationships among them.
Example: below we see a map of agricultural districts (in green) layered over soil types. We can see visual patterns in the data by determining what soil types are best suited for ag districts.
2. Mapping quantities. People map quantities, such as where the most and least are, to find places that meet their criteria or to see the relationships between places.
Example: below is a map of cemetery locations in Wisconsin. The map shows the cemetery locations as dots (dot density) and each county is color coded to show where the most and least are (lighter blue means fewer cemeteries).
3. Mapping densities. Sometimes it is more important to map concentrations, or a quantity normalized by area or total number. Example: Below we have mapped the population density of Manhattan (total population counts normalized by the area in sq. miles of census tracts.)
4. Finding what is inside. We can use GIS to determine what is happening or what features are located inside a specific area/region. We can determine the characteristics of "inside" by creating specific criteria to define an area of interest (AOI). Example: below is a map showing noise 'pollution' near an airport in Minneapolis. If we add demographic data from the Census to this map we can determine the socioeconomic characteristics of people that live within the defined 'noise pollution' area of interest.
5. Finding what is nearby. We can find out what is happening within a set distance of a feature or event by mapping what is nearby using geoprocessing tools like BUFFER. Example: below we see the effects on features within specified radii of a simulated explosion. Use of buffering tools to generate set distances can aid in emergency response to disasters like these.
6. Mapping change. We can map the change in a specific geographic area to anticipate future conditions, decide on a course of action, or to evaluate the results of an action or policy. Example: below we see land use maps of Barnstable, MA showing changes in residential development from 1951 to 1999. The dark green shows forest, while bright yellow shows residential development. Applications like this can help inform community planning processes and policies.
Q-3) Explain applications of GIS.
1. Natural Resources Management – inventory and management of agriculture crops, land cover and land use, forestry resources, soils, land degradation and wasteland management, water resources etc. towards establishing a Natural Resources Information System using Land Capability and Suitability models.
2. Disaster Management Support – where applications of GIS for vulnerability assessment, damage assessment rehab/relief works etc. can form a foundation.
3. Land records with a Land Information System (LIS) – where land records computerization with the cadastral maps can provide innovative land management solutions and public enterprises.
4. Urban Management, property and taxation applications as part of an urban GIS where multi-scale GIS solutions for planning and administration of urban areas and optimizing tax collection can be enabled.
5. Rural Applications of watershed management, rural roads management, village development planning and rural governance services
6. Defence & Security applications – a variety of command/control, battlefield management, Image Intelligence and other critical solutions that can support police and homeland security requirements
7. Aviation GIS to support Airports Asset management and air-traffic control requirements apart from airport environment management
8. Utility GIS - Telecom GIS to support fixed and mobile telecom services (including Location Based Services); Power-GIS solutions that allow effectively managing power generation, power distribution and Billing solutions
9. GIS Applications for Oil and Gas – integration of geophysical, images and maps to decide where to drill, route a pipeline, or build a refinery and make the right business decisions.
10. GIS Applications on Web and Wireless Systems offering GIS services on a variety of devices – internet, desktop, hand-held, mobile etc. GIS on small hand-held terminals (like PDAs) is also provided.
11. 3-D GIS solutions – based on converting 2-dimensional maps, extruding the polygons to create polygon-blocks and attributing text to these polygons (from library or actual pictures) to create a 3D visualization. Such 3-D GIS solution has immense applications in Urban, Security, Tourism and Real-Estate applications.
12. Other GIS Applications – Mining & Exploration, Insurance, Retail Business etc.
Q-4) Explain components of GIS.
GIS Hardware:-
Hardware is the computer on which a GIS operates. Today, GIS runs on a
wide range of hardware types, from centralized computer servers to desktop computers used in standalone or networked configurations.
GIS Software:-
GIS software provides the functions and tools needed to store, analyze, and display geographic information. Key software components are
1. a database management system (DBMS)
2. tools for the input and manipulation of geographic information
3. tools that support geographic query, analysis, and visualization
4. a graphical user interface (GUI) for easy access to tools
GIS Data: -
Maybe the most important component of a GIS is the data. Geographic data and related tabular data can be collected in-house or bought from a commercial data provider. Most GISs employ a DBMS to create and maintain a database to help organize and manage data.
People:-
GIS technology is of limited value without the people who manage the system and to develop plans for applying it. GIS users range from technical specialists who design and maintain the system to those who use it to help them do their everyday work.
Methods:-
A successful GIS operates according to a well-designed plan and business rules, which are the models and operating practices unique to each organization.
Q-5) What Is Geospatial Data?
01. Geospatial data are data that describe both the location and characteristics of spatial features such as roads, land parcels and vegetable stands on the earth’s surface.
02. The location, also called geometry or shape also represents spatial data.
03. The characteristics are attribute data.
04. Thus any geospatial data has the two components of spatial data and attribute data.
Spatial Data:-
01. Spatial data describes the location of spatial feature.
02. It may be discrete or continuous.
03. Discrete features are individually distinguishable features that do not exist between observations. E.g. Points (e.g. Wells), lines (roads) etc. areas (state boundaries).
04. Continuous features are features that exist spatially between observations. E.g. Elevations and precipitations.
05. A GIS represents these spatial features on earth surface as map feature on plane surface.
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