Computer And Internet Essay In Punjabi
Kristy Suzuki
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 information 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.
Cartographic data are already in map form, and may include such information as the location of rivers, roads, hills, and valleys. Cartographic data may also include survey data and mapping information that can be directly entered into a GIS.
Finally, GIS can also include data in table or spreadsheet form, such as population demographics. Demographics can range from age, income, and ethnicity to recent purchases and internet browsing preferences.
GIS technology allows all these different types of information, no matter their source or original format, to be overlaid on top of one another on a single map. GIS uses location as the key index variable to relate these seemingly unrelated data.
Putting information into GIS is called data capture. Data that are already in digital form, such as most tables and images taken by satellites, can simply be uploaded into GIS. Maps, however, must first be scanned, or converted to digital format.
The two major types of GIS file formats are raster and vector. Raster formats are grids of cells or pixels. Raster formats are useful for storing GIS data that vary, such as elevation or satellite imagery. Vector formats are polygons that use points (called nodes) and lines. Vector formats are useful for storing GIS data with firm borders, such as school districts or streets.
GIS technology can be used to display spatial relationships and linear networks. Spatial relationships may display topography, such as agricultural fields and streams. They may also display land-use patterns, such as the location of parks and housing complexes.
Linear networks, sometimes called geometric networks, are often represented by roads, rivers, and public utility grids in a GIS. A line on a map may indicate a road or highway. With GIS layers, however, that road may indicate the boundary of a school district, public park, or other demographic or land-use area. Using diverse data capture, the linear network of a river may be mapped on a GIS to indicate the stream flow of different tributaries.
GIS must make the information from all the various maps and sources align, so they fit together on the same scale. A scale is the relationship between the distance on a map and the actual distance on Earth.
Once all the desired data have been entered into a GIS system, they can be combined to produce a wide variety of individual maps, depending on which data layers are included. One of the most common uses of GIS technology involves comparing natural features with human activity.
With GIS technology, researchers can also look at change over time. They can use satellite data to study topics such as the advance and retreat of ice cover in polar regions, and how that coverage has changed through time. A police precinct might study changes in crime data to help determine where to assign officers.
One important use of time-based GIS technology involves creating time-lapse photography that shows processes occurring over large areas and long periods of time. For example, data showing the movement of fluid in ocean or air currents help scientists better understand how moisture and heat energy move around the globe.
GIS technology sometimes allows users to access further information about specific areas on a map. A person can point to a spot on a digital map to find other information stored in the GIS about that location. For example, a user might click on a school to find how many students are enrolled, how many students there are per teacher, or what sports facilities the school has.
GIS technology makes updating maps much easier than updating maps created manually. Updated data can simply be added to the existing GIS program. A new map can then be printed or displayed on screen. This skips the traditional process of drawing a map, which can be time-consuming and expensive.
City, state, or federal officials use GIS to help plan their response in the case of a natural disaster such as an earthquake or hurricane. GIS maps can show these officials what neighborhoods are most in danger, where to locate emergency shelters, and what routes people should take to reach safety.
Engineers use GIS technology to support the design, implementation, and management of communication networks for the phones we use, as well as the infrastructure necessary for internet connectivity. Other engineers may use GIS to develop road networks and transportation infrastructure.
There is no limit to the kind of information that can be analyzed using GIS technology.
The National Geographic Society is making this content available under a Creative Commons CC-BY-NC-SA license. The License excludes the National Geographic Logo (meaning the words National Geographic + the Yellow Border Logo) and any images that are included as part of each content piece. For clarity the Logo and images may not be removed, altered, or changed in any way.
Earth Science Information Center
To find out more about how GIS is used in your local community, contact your nearest Earth Science Information Center (ESIC). Staff from the US Geological Survey (USGS) answer questions about aerial photographs, maps, satellite imagery, computer programs, data formats, data standards, and digital cartographic data. To contact your local ESIC, call 1-888-ASK-USGS or visit the website.
Photozincography
The labor-intensive process of photozincography anticipated GIS in the 19th century. This process used zinc plates to draft different layers of a map, and a large-process camera to combine the layers into a single image.
The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.
For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.
A computer network is a group of interconnected nodes or computing devices that exchange data and resources with each other. A network connection between these devices can be established using cable or wireless media. Once a connection is established, communication protocols -- such as TCP/IP, Simple Mail Transfer Protocol and Hypertext Transfer Protocol -- are used to exchange data between the networked devices.
Devices attached to a computer network use IP addresses that are resolved into hostnames through a domain name system server to communicate with each other over the internet and on other computer networks. A variety of protocols and algorithms are also used to specify the transmission of data among endpoints.
Network systems must follow certain standards or guidelines to operate. Standards are a set of data communication rules required for the exchange of information between devices and are developed by various standards organizations, including IEEE, the International Organization for Standardization and the American National Standards Institute. For example, the Ethernet standard establishes a common communication language for wired or physical networks, and the 802.11 standard specifies connectivity for wireless local area networks (WLANs).
A computer network must be physically and logically designed in such a way that makes it possible for the underlying network elements to communicate with each other. This layout of a computer network is known as the computer network architecture.
A well-defined computer network also takes network capacity into account. A network's capacity is how much traffic the network can support at any given time, while still meeting service-level agreements. It's measured in terms of bandwidth, which is quantified by the theoretical maximum number of bits per second that can pass through a network device.
There are several types of computer networks. Which network an organization uses depends on factors such as the number of devices, types of operating systems, transmission medium used, network topology, the distance between each device and their geographic scale.
A network topology is the physical and logical arrangement of a network. All topologies come with different pros and cons. Organizations should consider the scope of a network -- including its size, scaling needs and business goals -- before selecting a particular topology.
Majorities of adults in each of the 11 emerging and developing countries surveyed report owning their own mobile phone. Ownership levels are highest in Vietnam, where nearly all adults (97%) own a mobile device, although about nine-in-ten or more also own one in Jordan, Tunisia, Colombia, Kenya, Lebanon and South Africa. Ownership is lowest in Venezuela, India and the Philippines, but even in these countries about seven-in-ten adults own a mobile device.
In all countries surveyed, adults with a secondary education or higher are more likely to own their own mobile phone than are those with less than a secondary education. These educational gaps in ownership range from just 3 percentage points in Vietnam to 35 points in the Philippines.
c80f0f1006