Advantages And Disadvantages Of Geographical Information Systems Pdf


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A geographic information system GIS , or geographical information system , captures, stores, analyzes, manages, and presents data that is linked to location. Technically, GIS is geographic information systems which includes mapping software and its application with remote sensing , land surveying, aerial photography , mathematics, photogrammetry , geography , and tools that can be implemented with GIS software. Still, many refer to "geographic information system" as GIS even though it doesn't cover all tools connected to topology. In the strictest sense, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. In a more generic sense, GIS applications are tools that allow users to create interactive queries user created searches , analyze spatial information, edit data, maps, and present the results of all these operations.

Geographic information system

A geographic information system GIS , or geographical information system , captures, stores, analyzes, manages, and presents data that is linked to location. Technically, GIS is geographic information systems which includes mapping software and its application with remote sensing , land surveying, aerial photography , mathematics, photogrammetry , geography , and tools that can be implemented with GIS software. Still, many refer to "geographic information system" as GIS even though it doesn't cover all tools connected to topology.

In the strictest sense, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. In a more generic sense, GIS applications are tools that allow users to create interactive queries user created searches , analyze spatial information, edit data, maps, and present the results of all these operations.

Geographic Information Science is the science underlying the geographic concepts, applications and systems, taught in degree and GIS Certificate programs at many universities. GIS technology can be used for scientific investigations, resource management, asset management, archaeology, environmental impact assessment, urban planning, cartography , criminology, geographic history, marketing, logistics, Prospectivity Mapping, and other purposes.

For example, GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, GIS might be used to find wetlands that need protection from pollution, or GIS can be used by a company to site a new business location to take advantage of a previously under-served market. About 15, years ago, [1] on the walls of caves near Lascaux, France, Cro-Magnon hunters drew pictures of the animals they hunted.

While simplistic in comparison to modern technologies, these early records mimic the two-element structure of modern GIS, an image associated with attribute information. The early 20th century saw the development of "photo lithography" where maps were separated into layers. Computer hardware development spurred by nuclear weapon research would lead to general purpose computer "mapping" applications by the early s.

Developed by Dr. Roger Tomlinson , it was called the " Canada Geographic Information System " CGIS and was used to store, analyze, and manipulate data collected for the Canada Land Inventory CLI —an initiative to determine the land capability for rural Canada by mapping information about soils, agriculture, recreation, wildlife, waterfowl, forestry, and land use at a scale of , A rating classification factor was also added to permit analysis.

It supported a national coordinate system that spanned the continent, coded lines as "arcs" having a true embedded topology, and it stored the attribute and locational information in separate files.

As a result of this, Tomlinson has become known as the "father of GIS," particularly for his use of overlays in promoting the spatial analysis of convergent geographic data. It was developed as a mainframe based system in support of federal and provincial resource planning and management. Its strength was continent-wide analysis of complex datasets. The CGIS was never available in a commercial form. In parallel, the development of two public domain systems began in the late s and early s.

Army Corps of Engineers to meet the need of the United States military for software for land management and environmental planning. The later s and s industry growth were spurred on by the growing use of GIS on Unix workstations and the personal computer.

By the end of the 20th century, the rapid growth in various systems had been consolidated and standardized on relatively few platforms and users were beginning to export the concept of viewing GIS data over the Internet, requiring data format and transfer standards.

More recently, there are a growing number of free, open source GIS packages which run on a range of operating systems and can be customized to perform specific tasks. Geographic information can be accessed, transferred, transformed, overlaid, processed and displayed using numerous software applications.

Although free tools exist to view GIS datasets, public access to geographic information is dominated by online resources such as Google Earth and interactive web mapping.

Originally up to the late s, when GIS data was mostly based on large computers and used to maintain internal records, software was a stand-alone product. However with increased access to the internet and networks and demand for distributed geographic data grew, GIS software gradually changed its entire outlook to the delivery of data over a network.

It helps to automate many complex processes without worrying about underlying algorithms and processing steps in conventional GIS software. Modern GIS technologies use digital information, for which various digitized data creation methods are used. The most common method of data creation is digitization, where a hard copy map or survey plan is transferred into a digital medium through the use of a computer-aided design CAD program, and geo-referencing capabilities.

With the wide availability of ortho-rectified imagery both from satellite and aerial sources , heads-up digitizing is becoming the main avenue through which geographic data is extracted. Heads-up digitizing involves the tracing of geographic data directly on top of the aerial imagery instead of by the traditional method of tracing the geographic form on a separate digitizing tablet heads-down digitizing.

You might be able to tell which wetlands dry up at certain times of the year. Using information from many different sources in many different forms, GIS can help with such analysis.

The primary requirement for the source data consists of knowing the locations for the variables. Location may be annotated by x, y, and z coordinates of longitude , latitude , and elevation, or by other geocode systems like ZIP Codes or by highway mile markers. Any variable that can be located spatially can be fed into a GIS.

Several computer databases that can be directly entered into a GIS are being produced by government agencies and non-government organizations [ citation needed ].

Different kinds of data in map form can be entered into a GIS. A GIS can also convert existing digital information, which may not yet be in map form, into forms it can recognize and use. For example, digital satellite images generated through remote sensing can be analyzed to produce a map-like layer of digital information about vegetative covers.

Another fairly recently developed resource for naming GIS objects is the Getty Thesaurus of Geographic Names GTGN , which is a structured vocabulary containing around 1,, names and other information about places. Likewise, census or hydrological tabular data can be converted to map-like form, serving as layers of thematic information in a GIS.

GIS data represents real world objects roads, land use, elevation with digital data. Real world objects can be divided into two abstractions: discrete objects a house and continuous fields rain fall amount or elevation. A raster data type is, in essence, any type of digital image represented in grids. Anyone who is familiar with digital photography will recognize the pixel as the smallest individual unit of an image.

A combination of these pixels will create an image, distinct from the commonly used scalable vector graphics which are the basis of the vector model. While a digital image is concerned with the output as representation of reality, in a photograph or art transferred to computer, the raster data type will reflect an abstraction of reality.

Aerial photos are one commonly used form of raster data, with only one purpose, to display a detailed image on a map or for the purposes of digitization. Raster data type consists of rows and columns of cells, with each cell storing a single value. Raster data can be images raster images with each pixel or cell containing a color value.

Additional values recorded for each cell may be a discrete value, such as land use, a continuous value, such as temperature, or a null value if no data is available.

While a raster cell stores a single value, it can be extended by using raster bands to represent RGB red, green, blue colors, colormaps a mapping between a thematic code and RGB value , or an extended attribute table with one row for each unique cell value. The resolution of the raster data set is its cell width in ground units. Database storage, when properly indexed, typically allows for quicker retrieval of the raster data but can require storage of millions of significantly-sized records.

In a GIS, geographical features are often expressed as vectors, by considering those features as geometrical shapes. Different geographical features are expressed by different types of geometry:. Each of these geometries is linked to a row in a database that describes their attributes. For example, a database that describes lakes may contain a lake's depth, water quality, pollution level.

This information can be used to make a map to describe a particular attribute of the dataset. For example, lakes could be coloured depending on level of pollution. Different geometries can also be compared. For example, the GIS could be used to identify all wells point geometry that are within 1-mile 1.

Vector features can be made to respect spatial integrity through the application of topology rules such as 'polygons must not overlap'. Vector data can also be used to represent continuously varying phenomena.

Contour lines and triangulated irregular networks TIN are used to represent elevation or other continuously changing values. TINs record values at point locations, which are connected by lines to form an irregular mesh of triangles. The face of the triangles represent the terrain surface. There are advantages and disadvantages to using a raster or vector data model to represent reality.

Raster datasets record a value for all points in the area covered which may require more storage space than representing data in a vector format that can store data only where needed. Raster data also allows easy implementation of overlay operations, which are more difficult with vector data. Vector data can be displayed as vector graphics used on traditional maps, whereas raster data will appear as an image that, depending on the resolution of the raster file, may have a blocky appearance for object boundaries.

Vector data can be easier to register, scale, and re-project. This can simplify combining vector layers from different sources.

Vector data is more compatible with relational database environments. They can be part of a relational table as a normal column and processed using a multitude of operators. The file size for vector data is usually much smaller for storage and sharing than raster data. Image or raster data can be 10 to times larger than vector data depending on the resolution. Another advantage of vector data is that it is easy to update and maintain. For example, a new highway is added. The raster image will have to be completely reproduced, but the vector data, "roads," can be easily updated by adding the missing road segment.

In addition, vector data allows much more analysis capability, especially for "networks" such as roads, power, rail, telecommunications, etc. For example, with vector data attributed with the characteristics of roads, ports, and airfields, allows the analyst to query for the best route or method of transportation.

In the vector data, the analyst can query the data for the largest port with an airfield within 60 miles and a connecting road that is at least two lane highway. Raster data will not have all the characteristics of the features it displays.

Additional non-spatial data can also be stored along with the spatial data represented by the coordinates of a vector geometry or the position of a raster cell. In vector data, the additional data contains attributes of the feature.

For example, a forest inventory polygon may also have an identifier value and information about tree species. In raster data the cell value can store attribute information, but it can also be used as an identifier that can relate to records in another table. There is also software being developed to support spatial and non-spatial decision-making.

In this software, the solutions to spatial problems are integrated with solutions to non-spatial problems. The end result it is hoped with these Flexible Spatial Decision-Making Support Systems FSDSS [10] will be that non experts can use GIS and spatial criteria with their other non spatial criteria to view solutions to multi-criteria problems that will support decision making.

Data capture—entering information into the system—consumes much of the time of GIS practitioners. There are a variety of methods used to enter data into a GIS where it is stored in a digital format. Existing data printed on paper or PET film maps can be digitized or scanned to produce digital data. A digitizer produces vector data as an operator traces points, lines, and polygon boundaries from a map.

GIS Data (Geographic Information Systems) uses, advantages and disadvantages

A geographic information system GIS is a conceptualized framework that provides the ability to capture and analyze spatial and geographic data. GIS applications or GIS apps are computer-based tools that allow the user to create interactive queries user-created searches , store and edit spatial and non-spatial data, analyze spatial information output, and visually share the results of these operations by presenting them as maps. Geographic information science or, GIScience —the scientific study of geographic concepts, applications, and systems—is commonly initialized as GIS, as well. Geographic information systems are utilized in multiple technologies, processes, techniques and methods. GIS provides the capability to relate previously unrelated information, through the use of location as the "key index variable". Locations and extents that are found in the Earth's spacetime , are able to be recorded through the date and time of occurrence, along with x, y, and z coordinates ; representing, longitude x , latitude y , and elevation z.

The decision to use vector or raster data models, or both, to encode geographical data is critical. The two data models have specific advantages and disadvantages but the decision can not be made on these alone. In essence the choice of data model will depend upon the intended users, the data, the system or systems and, most importantly, upon the application. Traditionally GIS data conversion technology was not available or not accurate enough for practical purpose so a user was bound to use the data model in which the source data is available. Also integration of data model is not possible in many cases. However, recently the integration among the data models and the algorithms used to rasterise or vectorise GIS data improved at a satisfactory level.

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A geographic information system is commonly referred to as a GIS , It is an integrated set of hardware and software tools used to manipulate and manage the digital spatial geographic and related attribute data. You know that Map making and geographic analysis are not new , but a GIS performs these tasks faster and with more sophistication than do traditional manual methods. Geographic Information System is a multi-billion-dollar industry employing hundreds of thousands of people worldwide , It is taught in the schools , colleges , and universities throughout the world.

Remote sensing technology, such as LiDAR , is used to acquire information about an object without making physical contact. But just like all technology, remote sensing comes with both advantages and disadvantages. Remote sensing has come a long way in recent years and is an impressive surveying technique with many different advantages. Remote sensing is a fast process.

Top Five Benefits of GIS

GIS benefits organizations of all sizes and in almost every industry. There is a growing interest in and awareness of the economic and strategic value of GIS, in part because of more standards-based technology and greater awareness of the benefits demonstrated by GIS users.

В это трудно было поверить, но она видела эти строки своими глазами. Электронная почта от Энсея Танкадо, адресованная Грегу Хейлу. Они работали .

Танкадо явно терял последние силы, но по-прежнему совал кольцо прямо в лицо тучному господину. Тот протянул руку, взял Танкадо за запястье, поддерживая остававшуюся на весу руку умирающего. Танкадо посмотрел вверх, на свои пальцы, на кольцо, а затем, умоляюще, - на тучного господина.

 Grazie! - просиял итальянец. Он швырнул Беккеру ключи от веспы, затем взял свою девушку за руку, и они, смеясь, побежали к зданию клуба. - Aspetta! - закричал Беккер.

Он не привык, чтобы кто-то повышал на него голос, пусть даже это был его главный криптограф. Он немного смешался. Сьюзан напряглась как тигрица, защищающая своего детеныша. - Сьюзан, ты же говорила с. Разве Дэвид тебе не объяснил.

Если кто-то в этой комнате считает, что ключ к шифру-убийце содержится еще где-то, помимо этого кольца, я готов его выслушать.  - Директор выдержал паузу. Никто не проронил ни слова. Он снова посмотрел на Джаббу и закрыл .

What Are the Advantages and Disadvantages of Remote Sensing?

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2 Comments

Elisabeth C.
03.04.2021 at 14:33 - Reply

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Ian G.
07.04.2021 at 12:30 - Reply

But ask these same folks about how topology is handled in shapefiles and the nodding heads give way to shrugging shoulders.

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