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93-509: The Advanced Spaceborne Thermal Emission and Reflection Radiometer ( ASTER ) is a Japanese remote sensing instrument onboard the Terra satellite launched by NASA in 1999. It has been collecting data since February 2000. ASTER provides high-resolution images of Earth in 14 different bands of the electromagnetic spectrum , ranging from visible to thermal infrared light. The resolution of images ranges between 15 and 90 meters. ASTER data
186-574: A knowledge worker in performing research and making decisions, including steps such as: Stewart (2001) argues that transformation of information into knowledge is critical, lying at the core of value creation and competitive advantage for the modern enterprise. In a biological framework, Mizraji has described information as an entity emerging from the interaction of patterns with receptor systems (eg: in molecular or neural receptors capable of interacting with specific patterns, information emerges from those interactions). In addition, he has incorporated
279-694: A degree or two with electronic compasses. Compasses can measure not just azimuth (i. e. degrees to magnetic north), but also altitude (degrees above the horizon), since the magnetic field curves into the Earth at different angles at different latitudes. More exact orientations require gyroscopic-aided orientation , periodically realigned by different methods including navigation from stars or known benchmarks. The quality of remote sensing data consists of its spatial, spectral, radiometric and temporal resolutions. In order to create sensor-based maps, most remote sensing systems expect to extrapolate sensor data in relation to
372-435: A function must exist, even if it is not accessible for humans; A view surmised by Albert Einstein with the assertion that " God does not play dice ". Modern astronomy cites the mechanical sense of information in the black hole information paradox , positing that, because the complete evaporation of a black hole into Hawking radiation leaves nothing except an expanding cloud of homogeneous particles, this results in
465-554: A great deal of data handling overhead. These data tend to be generally more useful for many applications. The regular spatial and temporal organization of Level 3 datasets makes it feasible to readily combine data from different sources. While these processing levels are particularly suitable for typical satellite data processing pipelines, other data level vocabularies have been defined and may be appropriate for more heterogeneous workflows. Satellite images provide very useful information to produce statistics on topics closely related to
558-825: A large extent of geography. At the same time, the data is often complex to interpret, and bulky to store. Modern systems tend to store the data digitally, often with lossless compression . The difficulty with this approach is that the data is fragile, the format may be archaic, and the data may be easy to falsify. One of the best systems for archiving data series is as computer-generated machine-readable ultrafiche , usually in typefonts such as OCR-B , or as digitized half-tone images. Ultrafiches survive well in standard libraries, with lifetimes of several centuries. They can be created, copied, filed and retrieved by automated systems. They are about as compact as archival magnetic media, and yet can be read by human beings with minimal, standardized equipment. Generally speaking, remote sensing works on
651-484: A legend of mapped classes that suits our purpose, taking again the example of wheat. The straightforward approach is counting the number of pixels classified as wheat and multiplying by the area of each pixel. Many authors have noticed that estimator is that it is generally biased because commission and omission errors in a confusion matrix do not compensate each other The main strength of classified satellite images or other indicators computed on satellite images
744-456: A more continuous form. Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation. The concept of information is relevant or connected to various concepts, including constraint , communication , control , data , form , education , knowledge , meaning , understanding , mental stimuli , pattern , perception , proposition , representation , and entropy . Information
837-434: A nutritional function. The cognitive scientist and applied mathematician Ronaldo Vigo argues that information is a concept that requires at least two related entities to make quantitative sense. These are, any dimensionally defined category of objects S, and any of its subsets R. R, in essence, is a representation of S, or, in other words, conveys representational (and hence, conceptual) information about S. Vigo then defines
930-553: A posed question. Whether the answer provides knowledge depends on the informed person. So a generalized definition of the concept should be: "Information" = An answer to a specific question". When Marshall McLuhan speaks of media and their effects on human cultures, he refers to the structure of artifacts that in turn shape our behaviors and mindsets. Also, pheromones are often said to be "information" in this sense. These sections are using measurements of data rather than information, as information cannot be directly measured. It
1023-472: A reference point including distances between known points on the ground. This depends on the type of sensor used. For example, in conventional photographs, distances are accurate in the center of the image, with the distortion of measurements increasing the farther you get from the center. Another factor is that of the platen against which the film is pressed can cause severe errors when photographs are used to measure ground distances. The step in which this problem
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#17327918309141116-679: A sample with less accurate, but exhaustive, data for a covariable or proxy that is cheaper to collect. For agricultural statistics, field surveys are usually required, while photo-interpretation may better for land cover classes that can be reliably identified on aerial photographs or high resolution satellite images. Additional uncertainty can appear because of imperfect reference data (ground truth or similar). Some options are: ratio estimator , regression estimator , calibration estimators and small area estimators If we target other variables, such as crop yield or leaf area , we may need different indicators to be computed from images, such as
1209-398: A type of input to an organism or system . Inputs are of two kinds; some inputs are important to the function of the organism (for example, food) or system ( energy ) by themselves. In his book Sensory Ecology biophysicist David B. Dusenbery called these causal inputs. Other inputs (information) are important only because they are associated with causal inputs and can be used to predict
1302-901: Is entropy . Entropy quantifies the amount of uncertainty involved in the value of a random variable or the outcome of a random process . For example, identifying the outcome of a fair coin flip (with two equally likely outcomes) provides less information (lower entropy) than specifying the outcome from a roll of a die (with six equally likely outcomes). Some other important measures in information theory are mutual information , channel capacity, error exponents , and relative entropy . Important sub-fields of information theory include source coding , algorithmic complexity theory , algorithmic information theory , and information-theoretic security . Applications of fundamental topics of information theory include source coding/ data compression (e.g. for ZIP files ), and channel coding/ error detection and correction (e.g. for DSL ). Its impact has been crucial to
1395-434: Is a major concept in both classical physics and quantum mechanics , encompassing the ability, real or theoretical, of an agent to predict the future state of a system based on knowledge gathered during its past and present. Determinism is a philosophical theory holding that causal determination can predict all future events, positing a fully predictable universe described by classical physicist Pierre-Simon Laplace as "
1488-504: Is a set that the sender and receiver of information must know before exchanging information. Digital information, for example, consists of building blocks that are all number sequences. Each number sequence represents a selection from its domain. The sender and receiver of digital information (number sequences) must know the domain and binary format of each number sequence before exchanging information. By defining number sequences online, this would be systematically and universally usable. Before
1581-420: Is always conveyed as the content of a message. Information can be encoded into various forms for transmission and interpretation (for example, information may be encoded into a sequence of signs , or transmitted via a signal ). It can also be encrypted for safe storage and communication. The uncertainty of an event is measured by its probability of occurrence. Uncertainty is inversely proportional to
1674-606: Is an abstract concept that refers to something which has the power to inform . At the most fundamental level, it pertains to the interpretation (perhaps formally ) of that which may be sensed , or their abstractions . Any natural process that is not completely random and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artifacts such as analogue signals , poems , pictures , music or other sounds , and currents convey information in
1767-532: Is an uncountable mass noun . Information theory is the scientific study of the quantification , storage , and communication of information. The field itself was fundamentally established by the work of Claude Shannon in the 1940s, with earlier contributions by Harry Nyquist and Ralph Hartley in the 1920s. The field is at the intersection of probability theory , statistics , computer science, statistical mechanics , information engineering , and electrical engineering . A key measure in information theory
1860-639: Is considerably lower, and not as good as that of SRTM data, and serious artifacts are present. Some of these limitations have been confirmed by METI and NASA, who point out that the version 1 of the GDEM product is "research grade". During October 2011, version 2 of Global Digital Elevation Model was publicly released. This is considered an improvement upon version 1. These improvements include increased horizontal and vertical accuracy, better horizontal resolution, reduced presence of artifacts, and more realistic values over water bodies. However, one reviewer still regards
1953-562: Is detected by the sensor) and "passive" remote sensing (when the reflection of sunlight is detected by the sensor). Remote sensing can be divided into two types of methods: Passive remote sensing and Active remote sensing. Passive sensors gather radiation that is emitted or reflected by the object or surrounding areas. Reflected sunlight is the most common source of radiation measured by passive sensors. Examples of passive remote sensors include film photography , infrared , charge-coupled devices , and radiometers . Active collection, on
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#17327918309142046-472: Is estimated that the world's technological capacity to store information grew from 2.6 (optimally compressed) exabytes in 1986 – which is the informational equivalent to less than one 730-MB CD-ROM per person (539 MB per person) – to 295 (optimally compressed) exabytes in 2007. This is the informational equivalent of almost 61 CD-ROM per person in 2007. The world's combined technological capacity to receive information through one-way broadcast networks
2139-416: Is forecast to increase rapidly, reaching 64.2 zettabytes in 2020. Over the next five years up to 2025, global data creation is projected to grow to more than 180 zettabytes. Records are specialized forms of information. Essentially, records are information produced consciously or as by-products of business activities or transactions and retained because of their value. Primarily, their value is as evidence of
2232-604: Is impossible to directly measure temperatures in the upper atmosphere, it is possible to measure the spectral emissions from a known chemical species (such as carbon dioxide) in that region. The frequency of the emissions may then be related via thermodynamics to the temperature in that region. To facilitate the discussion of data processing in practice, several processing "levels" were first defined in 1986 by NASA as part of its Earth Observing System and steadily adopted since then, both internally at NASA (e. g., ) and elsewhere (e. g., ); these definitions are: A Level 1 data record
2325-451: Is log 2 (4/1) = 2 bits. A 2011 Science article estimates that 97% of technologically stored information was already in digital bits in 2007 and that the year 2002 was the beginning of the digital age for information storage (with digital storage capacity bypassing analogue for the first time). Information can be defined exactly by set theory: "Information is a selection from the domain of information". The "domain of information"
2418-422: Is mainly (but not only, e.g. plants can grow in the direction of the light source) a causal input to plants but for animals it only provides information. The colored light reflected from a flower is too weak for photosynthesis but the visual system of the bee detects it and the bee's nervous system uses the information to guide the bee to the flower, where the bee often finds nectar or pollen, which are causal inputs,
2511-414: Is often processed iteratively: Data available at one step are processed into information to be interpreted and processed at the next step. For example, in written text each symbol or letter conveys information relevant to the word it is part of, each word conveys information relevant to the phrase it is part of, each phrase conveys information relevant to the sentence it is part of, and so on until at
2604-418: Is providing cheap information on the whole target area or most of it. This information usually has a good correlation with the target variable (ground truth) that is usually expensive to observe in an unbiased and accurate way. Therefore it can be observed on a probabilistic sample selected on an area sampling frame . Traditional survey methodology provides different methods to combine accurate information on
2697-438: Is put to use when the business subsequently wants to identify the most popular or least popular dish. Information can be transmitted in time, via data storage , and space, via communication and telecommunication . Information is expressed either as the content of a message or through direct or indirect observation . That which is perceived can be construed as a message in its own right, and in that sense, all information
2790-450: Is relevant to highlight that probabilistic sampling is not critical for the selection of training pixels for image classification, but it is necessary for accuracy assessment of the classified images and area estimation. Additional care is recommended to ensure that training and validation datasets are not spatially correlated. We suppose now that we have classified images or a land cover map produced by visual photo-interpretation, with
2883-432: Is resolved is called georeferencing and involves computer-aided matching of points in the image (typically 30 or more points per image) which is extrapolated with the use of an established benchmark, "warping" the image to produce accurate spatial data. As of the early 1990s, most satellite images are sold fully georeferenced. In addition, images may need to be radiometrically and atmospherically corrected. Interpretation
Advanced Spaceborne Thermal Emission and Reflection Radiometer - Misplaced Pages Continue
2976-489: Is that of examined areas or objects that reflect or emit radiation that stand out from surrounding areas. For a summary of major remote sensing satellite systems see the overview table. To coordinate a series of large-scale observations, most sensing systems depend on the following: platform location and the orientation of the sensor. High-end instruments now often use positional information from satellite navigation systems . The rotation and orientation are often provided within
3069-402: Is that of increasingly smaller sensor pods such as those used by law enforcement and the military, in both manned and unmanned platforms. The advantage of this approach is that this requires minimal modification to a given airframe. Later imaging technologies would include infrared, conventional, Doppler and synthetic aperture radar. The development of artificial satellites in the latter half of
3162-440: Is the critical process of making sense of the data. The first application was that of aerial photographic collection which used the following process; spatial measurement through the use of a light table in both conventional single or stereographic coverage, added skills such as the use of photogrammetry, the use of photomosaics, repeat coverage, Making use of objects' known dimensions in order to detect modifications. Image Analysis
3255-560: Is the most fundamental (i. e., highest reversible level) data record that has significant scientific utility, and is the foundation upon which all subsequent data sets are produced. Level 2 is the first level that is directly usable for most scientific applications; its value is much greater than the lower levels. Level 2 data sets tend to be less voluminous than Level 1 data because they have been reduced temporally, spatially, or spectrally. Level 3 data sets are generally smaller than lower level data sets and thus can be dealt with without incurring
3348-424: Is the recently developed automated computer-aided application that is in increasing use. Object-Based Image Analysis (OBIA) is a sub-discipline of GIScience devoted to partitioning remote sensing (RS) imagery into meaningful image-objects, and assessing their characteristics through spatial, spectral and temporal scale. Old data from remote sensing is often valuable because it may provide the only long-term data for
3441-565: Is used to create detailed maps of surface temperature of land, emissivity , reflectance , and elevation. In April 2008, the SWIR detectors of ASTER began malfunctioning and were publicly declared non-operational by NASA in January 2009. All SWIR data collected after 1 April 2008 has been marked as unusable. The ASTER Global Digital Elevation Model (GDEM) is available at no charge to users worldwide via electronic download. As of 2 April 2016,
3534-613: The Amazon Basin , glacial features in Arctic and Antarctic regions, and depth sounding of coastal and ocean depths. Military collection during the Cold War made use of stand-off collection of data about dangerous border areas. Remote sensing also replaces costly and slow data collection on the ground, ensuring in the process that areas or objects are not disturbed. Orbital platforms collect and transmit data from different parts of
3627-1023: The EGU or Digital Earth encourage the development of learning modules and learning portals . Examples include: FIS – Remote Sensing in School Lessons , Geospektiv , Ychange , or Spatial Discovery, to promote media and method qualifications as well as independent learning. Remote sensing data are processed and analyzed with computer software, known as a remote sensing application . A large number of proprietary and open source applications exist to process remote sensing data. There are applications of gamma rays to mineral exploration through remote sensing. In 1972 more than two million dollars were spent on remote sensing applications with gamma rays to mineral exploration. Gamma rays are used to search for deposits of uranium. By observing radioactivity from potassium, porphyry copper deposits can be located. A high ratio of uranium to thorium has been found to be related to
3720-556: The European Commission . Forest area and deforestation estimation have also been a frequent target of remote sensing projects, the same as land cover and land use Ground truth or reference data to train and validate image classification require a field survey if we are targetting annual crops or individual forest species, but may be substituted by photointerpretation if we look at wider classes that can be reliably identified on aerial photos or satellite images. It
3813-579: The Magellan spacecraft provided detailed topographic maps of Venus , while instruments aboard SOHO allowed studies to be performed on the Sun and the solar wind , just to name a few examples. Recent developments include, beginning in the 1960s and 1970s, the development of image processing of satellite imagery . The use of the term "remote sensing" began in the early 1960s when Evelyn Pruitt realized that advances in science meant that aerial photography
Advanced Spaceborne Thermal Emission and Reflection Radiometer - Misplaced Pages Continue
3906-536: The MetOp spacecraft of EUMETSAT are all operated at altitudes of about 800 km (500 mi). The Proba-1 , Proba-2 and SMOS spacecraft of European Space Agency are observing the Earth from an altitude of about 700 km (430 mi). The Earth observation satellites of UAE, DubaiSat-1 & DubaiSat-2 are also placed in Low Earth orbits (LEO) orbits and providing satellite imagery of various parts of
3999-537: The NDVI , a good proxy to chlorophyll activity. The modern discipline of remote sensing arose with the development of flight. The balloonist G. Tournachon (alias Nadar ) made photographs of Paris from his balloon in 1858. Messenger pigeons, kites, rockets and unmanned balloons were also used for early images. With the exception of balloons, these first, individual images were not particularly useful for map making or for scientific purposes. Systematic aerial photography
4092-615: The electromagnetic spectrum , which in conjunction with larger scale aerial or ground-based sensing and analysis, provides researchers with enough information to monitor trends such as El Niño and other natural long and short term phenomena. Other uses include different areas of the earth sciences such as natural resource management , agricultural fields such as land usage and conservation, greenhouse gas monitoring , oil spill detection and monitoring, and national security and overhead, ground-based and stand-off collection on border areas. The basis for multispectral collection and analysis
4185-622: The 20th century allowed remote sensing to progress to a global scale as of the end of the Cold War. Instrumentation aboard various Earth observing and weather satellites such as Landsat , the Nimbus and more recent missions such as RADARSAT and UARS provided global measurements of various data for civil, research, and military purposes. Space probes to other planets have also provided the opportunity to conduct remote sensing studies in extraterrestrial environments, synthetic aperture radar aboard
4278-560: The ASTER archive was used to create the ASTER GDEM, which included stereo-correlation to create individual scene-based ASTER DEMs, masking to remove cloudy pixels, stacking all cloud-screened DEMs, removing residual bad values and outliers, averaging selected data to create final pixel values. Remote sensing Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with
4371-595: The Aster version 2 dataset, although showing 'a considerable improvement in the effective level of detail', to still be regarded as 'experimental or research grade' due to presence of artefacts. A 2014 study showed that over rugged mountainous terrain the ASTER version 2 data set can be a more accurate representation of the ground than the SRTM elevation model. ASTER v3 was released on August 5, 2019. The improved GDEM V3 adds additional stereo-pairs, improving coverage and reducing
4464-500: The Earth. To get global coverage with a low orbit, a polar orbit is used. A low orbit will have an orbital period of roughly 100 minutes and the Earth will rotate around its polar axis about 25° between successive orbits. The ground track moves towards the west 25° each orbit, allowing a different section of the globe to be scanned with each orbit. Most are in Sun-synchronous orbits . Information Information
4557-478: The German students use the services of Google Earth ; in 2006 alone the software was downloaded 100 million times. But studies have shown that only a fraction of them know more about the data they are working with. There exists a huge knowledge gap between the application and the understanding of satellite images. Remote sensing only plays a tangential role in schools, regardless of the political claims to strengthen
4650-601: The Global Digital Elevation Model is the most complete mapping of the earth ever made, covering 99% of its surface. The previous most comprehensive map, NASA's Shuttle Radar Topography Mission , covered approximately 80% of the Earth's surface, with a global resolution of 90 meters, and a resolution of 30 meters over the USA. The GDEM covers the planet from 83 degrees North to 83 degrees South (surpassing SRTM 's coverage of 56 °S to 60 °N), becoming
4743-435: The activities of the organization but they may also be retained for their informational value. Sound records management ensures that the integrity of records is preserved for as long as they are required. The international standard on records management, ISO 15489, defines records as "information created, received, and maintained as evidence and information by an organization or person, in pursuance of legal obligations or in
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#17327918309144836-419: The amount of information that R conveys about S as the rate of change in the complexity of S whenever the objects in R are removed from S. Under "Vigo information", pattern, invariance, complexity, representation, and information – five fundamental constructs of universal science – are unified under a novel mathematical framework. Among other things, the framework aims to overcome
4929-401: The association between signs and behaviour. Semantics can be considered as the study of the link between symbols and their referents or concepts – particularly the way that signs relate to human behavior. Syntax is concerned with the formalism used to represent a message. Syntax as an area studies the form of communication in terms of the logic and grammar of sign systems. Syntax is devoted to
5022-427: The biological order and participating in the development of multicellular organisms, precedes by millions of years the emergence of human consciousness and the creation of the scientific culture that produced the chemical nomenclature. Systems theory at times seems to refer to information in this sense, assuming information does not necessarily involve any conscious mind, and patterns circulating (due to feedback ) in
5115-403: The chosen language in terms of its agreed syntax and semantics. The sender codes the message in the language and sends the message as signals along some communication channel (empirics). The chosen communication channel has inherent properties that determine outcomes such as the speed at which communication can take place, and over what distance. The existence of information about a closed system
5208-415: The context of some social situation. The social situation sets the context for the intentions conveyed (pragmatics) and the form of communication. In a communicative situation intentions are expressed through messages that comprise collections of inter-related signs taken from a language mutually understood by the agents involved in the communication. Mutual understanding implies that agents involved understand
5301-495: The discovery of the Earth's Van Allen radiation belts . The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space. In 2008, more than 150 Earth observation satellites were in orbit, recording data with both passive and active sensors and acquiring more than 10 terabits of data daily. By 2021, that total had grown to over 950, with
5394-401: The effect of its past and the cause of its future ". Quantum physics instead encodes information as a wave function , which prevents observers from directly identifying all of its possible measurements . Prior to the publication of Bell's theorem , determinists reconciled with this behavior using hidden variable theories , which argued that the information necessary to predict the future of
5487-503: The entire catalogue of ASTER image data became publicly available online at no cost. It can be downloaded with a free registered account from either NASA's Earth Data Search delivery system or from the USGS Earth Explorer delivery system. On 29 June 2009, the Global Digital Elevation Model (GDEM) was released to the public. A joint operation between NASA and Japan's Ministry of Economy, Trade and Industry (METI),
5580-437: The exchanged digital number sequence, an efficient unique link to its online definition can be set. This online-defined digital information (number sequence) would be globally comparable and globally searchable. The English word "information" comes from Middle French enformacion/informacion/information 'a criminal investigation' and its etymon, Latin informatiō(n) 'conception, teaching, creation'. In English, "information"
5673-642: The farmer who plants his fields in a remote corner of the country knows its value." The development of remote sensing technology reached a climax during the Cold War with the use of modified combat aircraft such as the P-51 , P-38 , RB-66 and the F-4C , or specifically designed collection platforms such as the U2/TR-1 , SR-71 , A-5 and the OV-1 series both in overhead and stand-off collection. A more recent development
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#17327918309145766-417: The fields of media and methods apart from the mere visual interpretation of satellite images. Many teachers have great interest in the subject "remote sensing", being motivated to integrate this topic into teaching, provided that the curriculum is considered. In many cases, this encouragement fails because of confusing information. In order to integrate remote sensing in a sustainable manner organizations like
5859-417: The final step information is interpreted and becomes knowledge in a given domain . In a digital signal , bits may be interpreted into the symbols, letters, numbers, or structures that convey the information available at the next level up. The key characteristic of information is that it is subject to interpretation and processing. The derivation of information from a signal or message may be thought of as
5952-581: The first commercial satellite (IKONOS) collecting very high resolution imagery was launched. Remote Sensing has a growing relevance in the modern information society. It represents a key technology as part of the aerospace industry and bears increasing economic relevance – new sensors e.g. TerraSAR-X and RapidEye are developed constantly and the demand for skilled labour is increasing steadily. Furthermore, remote sensing exceedingly influences everyday life, ranging from weather forecasts to reports on climate change or natural disasters . As an example, 80% of
6045-412: The first earth mapping system that provides comprehensive coverage of the polar regions. It was created by compiling 1.3 million VNIR images taken by ASTER using single-pass stereoscopic correlation techniques, with terrain elevation measurements taken globally at 30-meter (98 ft) intervals. Despite the high nominal resolution, however, some reviewers have commented that the true resolution
6138-448: The formation and development of an organism without any need for a conscious mind. One might argue though that for a human to consciously define a pattern, for example a nucleotide, naturally involves conscious information processing. However, the existence of unicellular and multicellular organisms, with the complex biochemistry that leads, among other events, to the existence of enzymes and polynucleotides that interact maintaining
6231-401: The idea of "information catalysts", structures where emerging information promotes the transition from pattern recognition to goal-directed action (for example, the specific transformation of a substrate into a product by an enzyme, or auditory reception of words and the production of an oral response) The Danish Dictionary of Information Terms argues that information only provides an answer to
6324-895: The irrecoverability of any information about the matter to have originally crossed the event horizon , violating both classical and quantum assertions against the ability to destroy information. The information cycle (addressed as a whole or in its distinct components) is of great concern to information technology , information systems , as well as information science . These fields deal with those processes and techniques pertaining to information capture (through sensors ) and generation (through computation , formulation or composition), processing (including encoding, encryption, compression, packaging), transmission (including all telecommunication methods), presentation (including visualization / display methods), storage (such as magnetic or optical, including holographic methods ), etc. Information visualization (shortened as InfoVis) depends on
6417-403: The issue of signs with the context within which signs are used. The focus of pragmatics is on the intentions of living agents underlying communicative behaviour. In other words, pragmatics link language to action. Semantics is concerned with the meaning of a message conveyed in a communicative act. Semantics considers the content of communication. Semantics is the study of the meaning of signs –
6510-461: The largest number of satellites operated by US-based company Planet Labs . Most Earth observation satellites carry instruments that should be operated at a relatively low altitude. Most orbit at altitudes above 500 to 600 kilometers (310 to 370 mi). Lower orbits have significant air-drag , which makes frequent orbit reboost maneuvers necessary. The Earth observation satellites ERS-1, ERS-2 and Envisat of European Space Agency as well as
6603-465: The launch of the first artificial satellite, Sputnik 1 , by the Soviet Union on October 4, 1957. Sputnik 1 sent back radio signals, which scientists used to study the ionosphere . The United States Army Ballistic Missile Agency launched the first American satellite, Explorer 1 , for NASA's Jet Propulsion Laboratory on January 31, 1958. The information sent back from its radiation detector led to
6696-411: The limitations of Shannon-Weaver information when attempting to characterize and measure subjective information. Information is any type of pattern that influences the formation or transformation of other patterns. In this sense, there is no need for a conscious mind to perceive, much less appreciate, the pattern. Consider, for example, DNA . The sequence of nucleotides is a pattern that influences
6789-438: The multi-faceted concept of information in terms of signs and signal-sign systems. Signs themselves can be considered in terms of four inter-dependent levels, layers or branches of semiotics : pragmatics, semantics, syntax, and empirics. These four layers serve to connect the social world on the one hand with the physical or technical world on the other. Pragmatics is concerned with the purpose of communication. Pragmatics links
6882-533: The object, in contrast to in situ or on-site observation . The term is applied especially to acquiring information about Earth and other planets . Remote sensing is used in numerous fields, including geophysics , geography , land surveying and most Earth science disciplines (e.g. exploration geophysics , hydrology , ecology , meteorology , oceanography , glaciology , geology ). It also has military, intelligence, commercial, economic, planning, and humanitarian applications, among others. In current usage,
6975-436: The occurrence of a causal input at a later time (and perhaps another place). Some information is important because of association with other information but eventually there must be a connection to a causal input. In practice, information is usually carried by weak stimuli that must be detected by specialized sensory systems and amplified by energy inputs before they can be functional to the organism or system. For example, light
7068-476: The occurrence of artifacts. The refined production algorithm provides improved spatial resolution, increased horizontal and vertical accuracy. The ASTER GDEM V3 maintains the GeoTIFF format and the same gridding and tile structure as V1 and V2, with 30-meter postings and 1 x 1 degree tiles. Version 3 is claimed to have significant improvements over the previous release. Automated processing of 2.3 million scenes from
7161-594: The organization or to meet legal, fiscal or accountability requirements imposed on the organization. Willis expressed the view that sound management of business records and information delivered "...six key requirements for good corporate governance ...transparency; accountability; due process; compliance; meeting statutory and common law requirements; and security of personal and corporate information." Michael Buckland has classified "information" in terms of its uses: "information as process", "information as knowledge", and "information as thing". Beynon-Davies explains
7254-522: The other hand, emits energy in order to scan objects and areas whereupon a sensor then detects and measures the radiation that is reflected or backscattered from the target. RADAR and LiDAR are examples of active remote sensing where the time delay between emission and return is measured, establishing the location, speed and direction of an object. Remote sensing makes it possible to collect data of dangerous or inaccessible areas. Remote sensing applications include monitoring deforestation in areas such as
7347-852: The presence of hydrothermal copper deposits. Radiation patterns have also been known to occur above oil and gas fields, but some of these patterns were thought to be due to surface soils instead of oil and gas. An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit , including spy satellites and similar ones intended for non-military uses such as environmental monitoring , meteorology , cartography and others. The most common type are Earth imaging satellites, that take satellite images , analogous to aerial photographs ; some EO satellites may perform remote sensing without forming pictures, such as in GNSS radio occultation . The first occurrence of satellite remote sensing can be dated to
7440-412: The principle of the inverse problem : while the object or phenomenon of interest (the state ) may not be directly measured, there exists some other variable that can be detected and measured (the observation ) which may be related to the object of interest through a calculation. The common analogy given to describe this is trying to determine the type of animal from its footprints. For example, while it
7533-423: The probability of occurrence. Information theory takes advantage of this by concluding that more uncertain events require more information to resolve their uncertainty. The bit is a typical unit of information . It is 'that which reduces uncertainty by half'. Other units such as the nat may be used. For example, the information encoded in one "fair" coin flip is log 2 (2/1) = 1 bit, and in two fair coin flips
7626-487: The resolution of ambiguity or uncertainty that arises during the interpretation of patterns within the signal or message. Information may be structured as data . Redundant data can be compressed up to an optimal size, which is the theoretical limit of compression. The information available through a collection of data may be derived by analysis. For example, a restaurant collects data from every customer order. That information may be analyzed to produce knowledge that
7719-471: The specific context associated with this interpretation may cause the transformation of the information into knowledge . Complex definitions of both "information" and "knowledge" make such semantic and logical analysis difficult, but the condition of "transformation" is an important point in the study of information as it relates to knowledge, especially in the business discipline of knowledge management . In this practice, tools and processes are used to assist
7812-418: The study of the form rather than the content of signs and sign systems. Nielsen (2008) discusses the relationship between semiotics and information in relation to dictionaries. He introduces the concept of lexicographic information costs and refers to the effort a user of a dictionary must make to first find, and then understand data so that they can generate information. Communication normally exists within
7905-725: The success of the Voyager missions to deep space, the invention of the compact disc , the feasibility of mobile phones and the development of the Internet. The theory has also found applications in other areas, including statistical inference , cryptography , neurobiology , perception , linguistics, the evolution and function of molecular codes ( bioinformatics ), thermal physics , quantum computing , black holes , information retrieval , intelligence gathering , plagiarism detection , pattern recognition , anomaly detection and even art creation. Often information can be viewed as
7998-423: The support for teaching on the subject. A lot of the computer software explicitly developed for school lessons has not yet been implemented due to its complexity. Thereby, the subject is either not at all integrated into the curriculum or does not pass the step of an interpretation of analogue images. In fact, the subject of remote sensing requires a consolidation of physics and mathematics as well as competences in
8091-434: The system can be called information. In other words, it can be said that information in this sense is something potentially perceived as representation, though not created or presented for that purpose. For example, Gregory Bateson defines "information" as a "difference that makes a difference". If, however, the premise of "influence" implies that information has been perceived by a conscious mind and also interpreted by it,
8184-406: The term remote sensing generally refers to the use of satellite - or aircraft-based sensor technologies to detect and classify objects on Earth. It includes the surface and the atmosphere and oceans , based on propagated signals (e.g. electromagnetic radiation ). It may be split into "active" remote sensing (when a signal is emitted by a satellite or aircraft to the object and its reflection
8277-639: The territory, such as agriculture, forestry or land cover in general. The first large project to apply Landsata 1 images for statistics was LACIE (Large Area Crop Inventory Experiment), run by NASA, NOAA and the USDA in 1974–77. Many other application projects on crop area estimation have followed, including the Italian AGRIT project and the MARS project of the Joint Research Centre (JRC) of
8370-416: The transaction of business". The International Committee on Archives (ICA) Committee on electronic records defined a record as, "recorded information produced or received in the initiation, conduct or completion of an institutional or individual activity and that comprises content, context and structure sufficient to provide evidence of the activity". Records may be maintained to retain corporate memory of
8463-591: Was developed for military surveillance and reconnaissance purposes beginning in World War I . After WWI, remote sensing technology was quickly adapted to civilian applications. This is demonstrated by the first line of a 1941 textbook titled "Aerophotography and Aerosurverying," which stated the following: "There is no longer any need to preach for aerial photography-not in the United States- for so widespread has become its use and so great its value that even
8556-559: Was no longer an adequate term to describe the data streams being generated by new technologies. With assistance from her fellow staff member at the Office of Naval Research, Walter Bailey, she coined the term "remote sensing". Several research groups in Silicon Valley including NASA Ames Research Center , GTE , and ESL Inc. developed Fourier transform techniques leading to the first notable enhancement of imagery data. In 1999
8649-443: Was the informational equivalent of 174 newspapers per person per day in 2007. The world's combined effective capacity to exchange information through two-way telecommunication networks was the informational equivalent of 6 newspapers per person per day in 2007. As of 2007, an estimated 90% of all new information is digital, mostly stored on hard drives. The total amount of data created, captured, copied, and consumed globally
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