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In mathematics, Dirichlet's unit theorem is a basic result in algebraic number theory due to Peter Gustav Lejeune Dirichlet. It determines the rank of the group of units in the ring OK of algebraic integers of a number field K. The regulator is a positive real number that determines how "dense" the units are.
The state... | Wikipedia/Regulator_of_an_algebraic_number_field |
In mathematics, the discriminant of an algebraic number field is a numerical invariant that, loosely speaking, measures the size of the (ring of integers of the) algebraic number field. More specifically, it is proportional to the squared volume of the fundamental domain of the ring of integers, and it regulates which ... | Wikipedia/Discriminant_of_an_algebraic_number_field |
In mathematics, especially group theory, two elements
a
{\displaystyle a}
and
b
{\displaystyle b}
of a group are conjugate if there is an element
g
{\displaystyle g}
in the group such that... | Wikipedia/Class_equation |
Solution of triangles (Latin: solutio triangulorum) is the main trigonometric problem of finding the characteristics of a triangle (angles and lengths of sides), when some of these are known. The triangle can be located on a plane or on a sphere. Applications requiring triangle solutions include geodesy, astronomy, con... | Wikipedia/Solution_of_triangles |
Gauss's lemma in number theory gives a condition for an integer to be a quadratic residue. Although it is not useful computationally, it has theoretical significance, being involved in some proofs of quadratic reciprocity.
It made its first appearance in Carl Friedrich Gauss's third proof (1808): 458–462 of quadratic ... | Wikipedia/Gauss's_lemma_(number_theory) |
In data communications, flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. Flow control should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred. ... | Wikipedia/Flow_control_(data) |
In computer science, a control-flow graph (CFG) is a representation, using graph notation, of all paths that might be traversed through a program during its execution. The control-flow graph was conceived by Frances E. Allen, who noted that Reese T. Prosser used boolean connectivity matrices for flow analysis before.
T... | Wikipedia/Control-flow_graph |
In computer programming, a virtual method table (VMT), virtual function table, virtual call table, dispatch table, vtable, or vftable is a mechanism used in a programming language to support dynamic dispatch (or run-time method binding).
Whenever a class defines a virtual function (or method), most compilers add a hidd... | Wikipedia/Virtual_method_table |
The primary focus of this article is asynchronous control in digital electronic systems. In a synchronous system, operations (instructions, calculations, logic, etc.) are coordinated by one, or more, centralized clock signals. An asynchronous system, in contrast, has no global clock. Asynchronous systems do not de... | Wikipedia/Asynchronous_systems |
In computer science, control-flow analysis (CFA) is a static-code-analysis technique for determining the control flow of a program. The control flow is expressed as a control-flow graph (CFG). For both functional programming languages and object-oriented programming languages, the term CFA, and elaborations such as k-C... | Wikipedia/Control_flow_analysis |
In computer science, a generator is a routine that can be used to control the iteration behaviour of a loop. All generators are also iterators. A generator is very similar to a function that returns an array, in that a generator has parameters, can be called, and generates a sequence of values. However, instead of buil... | Wikipedia/Generator_(computer_science) |
In computer programming, a statement is a syntactic unit of an imperative programming language that expresses some action to be carried out. A program written in such a language is formed by a sequence of one or more statements. A statement may have internal components (e.g. expressions).
Many programming languages (e.... | Wikipedia/Statement_(computer_science) |
In mathematics, a unary function is a function that takes one argument. A unary operator belongs to a subset of unary functions, in that its codomain coincides with its domain. In contrast, a unary function's domain need not coincide with its range.
== Examples ==
The successor function, denoted
... | Wikipedia/Unary_function |
Control-flow integrity (CFI) is a general term for computer security techniques that prevent a wide variety of malware attacks from redirecting the flow of execution (the control flow) of a program.
== Background ==
A computer program commonly changes its control flow to make decisions and use different parts of the ... | Wikipedia/Control-flow_integrity |
A branch, jump or transfer is an instruction in a computer program that can cause a computer to begin executing a different instruction sequence and thus deviate from its default behavior of executing instructions in order. Branch (or branching, branched) may also refer to the act of switching execution to a different... | Wikipedia/Branch_(computer_science) |
A default, in computer science, refers to the preexisting value of a user-configurable setting that is assigned to a software application, computer program or device. Such settings are also called factory settings, or factory presets, especially for electronic devices.
Default values are standards values that are univ... | Wikipedia/Default_(computer_science) |
In programming languages, a label is a sequence of characters that identifies a location within source code. In most languages, labels take the form of an identifier, often followed by a punctuation character (e.g., a colon). In many high-level languages, the purpose of a label is to act as the destination of a GOTO ... | Wikipedia/Label_(computer_science) |
In computer programming a control break is a change in the value of one of the keys on which a file is sorted which requires some extra processing. For example, with an input file sorted by post code, the number of items found in each postal district might need to be printed on a report, and a heading shown for the nex... | Wikipedia/Control_break |
A control-flow diagram (CFD) is a diagram to describe the control flow of a business process, process or review.
Control-flow diagrams were developed in the 1950s, and are widely used in multiple engineering disciplines. They are one of the classic business process modeling methodologies, along with flow charts, drakon... | Wikipedia/Control-flow_diagram |
The Java Modeling Language (JML) is a specification language for Java programs, using Hoare style pre- and postconditions and invariants, that follows the design by contract paradigm. Specifications are written as Java annotation comments to the source files, which hence can be compiled with any Java compiler.
Various ... | Wikipedia/Java_Modeling_Language |
In mathematics, a profinite group is a topological group that is in a certain sense assembled from a system of finite groups.
The idea of using a profinite group is to provide a "uniform", or "synoptic", view of an entire system of finite groups. Properties of the profinite group are generally speaking uniform properti... | Wikipedia/Krull_topology |
In mathematics, particularly in algebra, a field extension is a pair of fields
K
⊆
L
{\displaystyle K\subseteq L}
, such that the operations of K are those of L restricted to K. In this case, L is an extension field of K and K is a subfield of L. For example, u... | Wikipedia/Adjunction_(field_theory) |
In group theory, a branch of mathematics, a torsion group or a periodic group is a group in which every element has finite order. The exponent of such a group, if it exists, is the least common multiple of the orders of the elements.
For example, it follows from Lagrange's theorem that every finite group is periodic a... | Wikipedia/Exponent_(group_theory) |
In mathematics, the Hardy–Ramanujan–Littlewood circle method is a technique of analytic number theory. It is named for G. H. Hardy, S. Ramanujan, and J. E. Littlewood, who developed it in a series of papers on Waring's problem.
== History ==
The initial idea is usually attributed to the work of Hardy with Srinivasa R... | Wikipedia/Hardy–Ramanujan–Littlewood_circle_method |
In mathematics, the Weierstrass elliptic functions are elliptic functions that take a particularly simple form. They are named for Karl Weierstrass. This class of functions is also referred to as ℘-functions and they are usually denoted by the symbol ℘, a uniquely fancy script p. They play an important role in the theo... | Wikipedia/Weierstrass_elliptic_functions |
In number theory, the prime omega functions
ω
(
n
)
{\displaystyle \omega (n)}
and
Ω
(
n
)
{\displaystyle \Omega (n)}
count the number of prime factors of a natural number
... | Wikipedia/Prime_omega_function |
In number theory, an average order of an arithmetic function is some simpler or better-understood function which takes the same values "on average".
Let
f
{\displaystyle f}
be an arithmetic function. We say that an average order of
f
{\... | Wikipedia/Average_order_of_an_arithmetic_function |
In mathematics, the Rankin–Selberg method, introduced by Rankin (1939) and Selberg (1940), also known as the theory of integral representations of L-functions, is a technique for directly constructing and analytically continuing several important examples of automorphic L-functions. Some authors reserve the term for a... | Wikipedia/Rankin–Selberg_method |
In number theory, functions of positive integers which respect products are important and are called completely multiplicative functions or totally multiplicative functions. A weaker condition is also important, respecting only products of coprime numbers, and such functions are called multiplicative functions. Outsi... | Wikipedia/Completely_multiplicative_function |
In number theory, the parity problem refers to a limitation in sieve theory that prevents sieves from giving good estimates in many kinds of prime-counting problems. The problem was identified and named by Atle Selberg in 1949. Beginning around 1996, John Friedlander and Henryk Iwaniec developed some parity-sensitive s... | Wikipedia/Parity_problem_(sieve_theory) |
A weight function is a mathematical device used when performing a sum, integral, or average to give some elements more "weight" or influence on the result than other elements in the same set. The result of this application of a weight function is a weighted sum or weighted average. Weight functions occur frequently in ... | Wikipedia/Weight_function |
In number theory, the fundamental lemma of sieve theory is any of several results that systematize the process of applying sieve methods to particular problems. Halberstam & Richert
: 92–93
write:
A curious feature of sieve literature is that while there is frequent use of Brun's method there are only a few attempts ... | Wikipedia/Fundamental_lemma_of_sieve_theory |
The chirp Z-transform (CZT) is a generalization of the discrete Fourier transform (DFT). While the DFT samples the Z plane at uniformly-spaced points along the unit circle, the chirp Z-transform samples along spiral arcs in the Z-plane, corresponding to straight lines in the S plane. The DFT, real DFT, and zoom DFT c... | Wikipedia/Chirp_Z-transform |
In mathematics, the discrete-time Fourier transform (DTFT) is a form of Fourier analysis that is applicable to a sequence of discrete values.
The DTFT is often used to analyze samples of a continuous function. The term discrete-time refers to the fact that the transform operates on discrete data, often samples whose in... | Wikipedia/Discrete-time_Fourier_transform |
The Goertzel algorithm is a technique in digital signal processing (DSP) for efficient evaluation of the individual terms of the discrete Fourier transform (DFT). It is useful in certain practical applications, such as recognition of dual-tone multi-frequency signaling (DTMF) tones produced by the push buttons of the k... | Wikipedia/Goertzel_algorithm |
Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics). It is the study of numerical methods that attempt to find approximate solutions of problems rather than the exact ... | Wikipedia/Numerical_algorithm |
The short-time Fourier transform (STFT) is a Fourier-related transform used to determine the sinusoidal frequency and phase content of local sections of a signal as it changes over time. In practice, the procedure for computing STFTs is to divide a longer time signal into shorter segments of equal length and then compu... | Wikipedia/Short-time_Fourier_transform |
In mathematics and signal processing, the Hilbert transform is a specific singular integral that takes a function, u(t) of a real variable and produces another function of a real variable H(u)(t). The Hilbert transform is given by the Cauchy principal value of the convolution with the function
... | Wikipedia/Discrete_Hilbert_transform |
The fast Fourier transform (FFT) is an important tool in the fields of image and signal processing. The hexagonal fast Fourier transform (HFFT) uses existing FFT routines to compute the discrete Fourier transform (DFT) of images that have been captured with hexagonal sampling. The hexagonal grid serves as the optimal ... | Wikipedia/Hexagonal_fast_Fourier_transform |
Intel Integrated Performance Primitives (Intel IPP) is an extensive library of ready-to-use, domain-specific functions that are highly optimized for diverse Intel architectures. Its royalty-free APIs help developers take advantage of single instruction, multiple data (SIMD) instructions.
The library supports Intel and ... | Wikipedia/Integrated_Performance_Primitives |
An astronomical interferometer or telescope array is a set of separate telescopes, mirror segments, or radio telescope antennas that work together as a single telescope to provide higher resolution images of astronomical objects such as stars, nebulas and galaxies by means of interferometry. The advantage of this tech... | Wikipedia/Fast_Fourier_Transform_Telescope |
The vector-radix FFT algorithm, is a multidimensional fast Fourier transform (FFT) algorithm, which is a generalization of the ordinary Cooley–Tukey FFT algorithm that divides the transform dimensions by arbitrary radices. It breaks a multidimensional (MD) discrete Fourier transform (DFT) down into successively smaller... | Wikipedia/Vector-radix_FFT_algorithm |
In quantum computing, the quantum Fourier transform (QFT) is a linear transformation on quantum bits, and is the quantum analogue of the discrete Fourier transform. The quantum Fourier transform is a part of many quantum algorithms, notably Shor's algorithm for factoring and computing the discrete logarithm, the quantu... | Wikipedia/Quantum_Fourier_transform |
In applied mathematics, the non-uniform discrete Fourier transform (NUDFT or NDFT) of a signal is a type of Fourier transform, related to a discrete Fourier transform or discrete-time Fourier transform, but in which the input signal is not sampled at equally spaced points or frequencies (or both). It is a generalizatio... | Wikipedia/Non-uniform_discrete_Fourier_transform |
The prime-factor algorithm (PFA), also called the Good–Thomas algorithm (1958/1963), is a fast Fourier transform (FFT) algorithm that re-expresses the discrete Fourier transform (DFT) of a size N = N1N2 as a two-dimensional N1 × N2 DFT, but only for the case where N1 and N2 are relatively prime. These smaller transform... | Wikipedia/Prime-factor_FFT_algorithm |
In mathematical analysis and applications, multidimensional transforms are used to analyze the frequency content of signals in a domain of two or more dimensions.
== Multidimensional Fourier transform ==
One of the more popular multidimensional transforms is the Fourier transform, which converts a signal from a time... | Wikipedia/Multidimensional_transform |
The fast multipole method (FMM) is a numerical technique that was developed to speed up the calculation of long-ranged forces in the n-body problem. It does this by expanding the system Green's function using a multipole expansion, which allows one to group sources that lie close together and treat them as if they are ... | Wikipedia/Fast_multipole_method |
The Cooley–Tukey algorithm, named after J. W. Cooley and John Tukey, is the most common fast Fourier transform (FFT) algorithm. It re-expresses the discrete Fourier transform (DFT) of an arbitrary composite size
N
=
N
1
... | Wikipedia/Cooley–Tukey_FFT_algorithm |
A discrete Hartley transform (DHT) is a Fourier-related transform of discrete, periodic data similar to the discrete Fourier transform (DFT), with analogous applications in signal processing and related fields. Its main distinction from the DFT is that it transforms real inputs to real outputs, with no intrinsic involv... | Wikipedia/Discrete_Hartley_transform |
In signal processing, overlap–save is the traditional name for an efficient way to evaluate the discrete convolution between a very long signal
x
[
n
]
{\displaystyle x[n]}
and a finite impulse response (FIR) filter
h
[
... | Wikipedia/Overlap–save_method |
Rader's algorithm (1968), named for Charles M. Rader of MIT Lincoln Laboratory, is a fast Fourier transform (FFT) algorithm that computes the discrete Fourier transform (DFT) of prime sizes by re-expressing the DFT as a cyclic convolution (the other algorithm for FFTs of prime sizes, Bluestein's algorithm, also works b... | Wikipedia/Rader's_FFT_algorithm |
In the mathematical field of representation theory, group representations describe abstract groups in terms of bijective linear transformations of a vector space to itself (i.e. vector space automorphisms); in particular, they can be used to represent group elements as invertible matrices so that the group operation ca... | Wikipedia/Group_representation_theory |
In mathematics, approximation theory is concerned with how functions can best be approximated with simpler functions, and with quantitatively characterizing the errors introduced thereby. What is meant by best and simpler will depend on the application.
A closely related topic is the approximation of functions by gener... | Wikipedia/Chebyshev_approximation |
The split-radix FFT is a fast Fourier transform (FFT) algorithm for computing the discrete Fourier transform (DFT), and was first described in an initially little-appreciated paper by R. Yavne (1968)[1] and subsequently rediscovered simultaneously by various authors in 1984. (The name "split radix" was coined by two of... | Wikipedia/Split-radix_FFT_algorithm |
In mathematics, the discrete Fourier transform over a ring generalizes the discrete Fourier transform (DFT), of a function whose values are commonly complex numbers, over an arbitrary ring.
== Definition ==
Let R be any ring, let
n
≥
1
{\displaystyle n\geq 1}
... | Wikipedia/Number-theoretic_transform |
The Schönhage–Strassen algorithm is an asymptotically fast multiplication algorithm for large integers, published by Arnold Schönhage and Volker Strassen in 1971. It works by recursively applying fast Fourier transform (FFT) over the integers modulo
2
n
... | Wikipedia/Schönhage–Strassen_algorithm |
The Fast-Folding Algorithm (FFA) is a computational method primarily utilized in the domain of astronomy for detecting periodic signals.
FFA is designed to reveal repeating or cyclical patterns by "folding" data, which involves dividing the data set into numerous segments, aligning these segments to a common phase, an... | Wikipedia/Fast_folding_algorithm |
In computational mathematics, the Hadamard ordered fast Walsh–Hadamard transform (FWHTh) is an efficient algorithm to compute the Walsh–Hadamard transform (WHT). A naive implementation of the WHT of order
n
=
2
m
... | Wikipedia/Fast_Walsh–Hadamard_transform |
In mathematics, the Fourier transform on finite groups is a generalization of the discrete Fourier transform from cyclic to arbitrary finite groups.
== Definitions ==
The Fourier transform of a function
f
:
G
→
C
{\displaystyl... | Wikipedia/Fourier_transform_on_finite_groups |
Bruun's algorithm is a fast Fourier transform (FFT) algorithm based on an unusual recursive polynomial-factorization approach, proposed for powers of two by G. Bruun in 1978 and generalized to arbitrary even composite sizes by H. Murakami in 1996. Because its operations involve only real coefficients until the last com... | Wikipedia/Bruun's_FFT_algorithm |
The chirp Z-transform (CZT) is a generalization of the discrete Fourier transform (DFT). While the DFT samples the Z plane at uniformly-spaced points along the unit circle, the chirp Z-transform samples along spiral arcs in the Z-plane, corresponding to straight lines in the S plane. The DFT, real DFT, and zoom DFT c... | Wikipedia/Chirp-z_algorithm |
In signal processing, the overlap–add method is an efficient way to evaluate the discrete convolution of a very long signal
x
[
n
]
{\displaystyle x[n]}
with a finite impulse response (FIR) filter
h
[
n
]... | Wikipedia/Overlap–add_method |
Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activitie... | Wikipedia/Hydrography |
Geographic Information Systems (GIS) has become an integral part of aquatic science and limnology. Water by its very nature is dynamic. Features associated with water are thus ever-changing. To be able to keep up with these changes, technological advancements have given scientists methods to enhance all aspects of s... | Wikipedia/GIS_and_aquatic_science |
The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite-based sensor used for earth and climate measurements. There are two MODIS sensors in Earth orbit: one on board the Terra (EOS AM) satellite, launched by NASA in 1999; and one on board the Aqua (EOS PM) satellite, launched in 2002. Since 2011, MODI... | Wikipedia/Moderate-resolution_imaging_spectroradiometer |
Children's geographies is an area of study within human geography and childhood studies which involves researching the places and spaces of children's lives.
== Context ==
Children's geographies is the branch of human geography which deals with the study of places and spaces of children's lives, characterised experie... | Wikipedia/Children's_geographies |
In business intelligence, location intelligence (LI), or spatial intelligence, is the process of deriving meaningful insight from geospatial data relationships to solve a particular problem. It involves layering multiple data sets spatially and/or chronologically, for easy reference on a map, and its applications span ... | Wikipedia/Spatial_intelligence_(business_method) |
Photozincography, sometimes referred to as heliozincography but essentially the same process, known commercially as zinco, is the photographic process developed by Sir Henry James FRS (1803–1877) in the mid-nineteenth century.
This method enabled the accurate reproduction of images, manuscript text and outline engravin... | Wikipedia/Photozincography |
A geographic information system (GIS) consists of integrated computer hardware and software that store, manage, analyze, edit, output, and visualize geographic data. Much of this often happens within a spatial database; however, this is not essential to meet the definition of a GIS. In a broader sense, one may consider... | Wikipedia/Geographic_Information_Systems |
A transport network, or transportation network, is a network or graph in geographic space, describing an infrastructure that permits and constrains movement or flow.
Examples include but are not limited to road networks, railways, air routes, pipelines, aqueducts, and power lines. The digital representation of these ne... | Wikipedia/Transport_network_analysis |
Geographic data and information is defined in the ISO/TC 211 series of standards as data and information having an implicit or explicit association with a location relative to Earth (a geographic location or geographic position). It is also called geospatial data and information, georeferenced data and information, as ... | Wikipedia/Geographic_data |
Intergraph Corporation was an American software development and services company, which now forms part of Hexagon AB. It provides enterprise engineering and geospatially powered software to businesses, governments, and organizations around the world, and operates through three divisions: Hexagon Asset Lifecycle Intelli... | Wikipedia/Intergraph |
In geography and particularly in geographic information science, a geographic feature or simply feature (also called an object or entity) is a representation of phenomenon that exists at a location in the space and scale of relevance to geography; that is, at or near the surface of Earth.: 62 It is an item of geograph... | Wikipedia/Geographical_feature |
Geographers on Film is an archival collection and series of more than 550 filmed interviews with experts of the geographic scholar community. This is a 40 year long initiative.
== Production ==
The series was created as an historical and educational resource by geographer and professor emeritus Maynard Weston Dow (1... | Wikipedia/Geographers_on_Film |
Geographic information science (GIScience, GISc) or geoinformation science is a scientific discipline at the crossroads of computational science, social science, and natural science that studies geographic information, including how it represents phenomena in the real world, how it represents the way humans understand ... | Wikipedia/GIScience |
Integrated Geo Systems (IGS) is a computational architecture system developed for managing geoscientific data through systems and data integration.
Geosciences often involve large volumes of diverse data which have to be processed by computer and graphics intensive applications. The processes involved in processing the... | Wikipedia/Integrated_Geo_Systems |
The concept of imagined geographies (or imaginative geographies) originated from Edward Said, particularly his work on critique on Orientalism. Imagined geographies refers to the perception of a space created through certain imagery, texts, and/or discourses. For Said, imagined does not mean to be false or made-up, but... | Wikipedia/Imagined_geographies |
A GIS software program is a computer program to support the use of a geographic information system, providing the ability to create, store, manage, query, analyze, and visualize geographic data, that is, data representing phenomena for which location is important. The GIS software industry encompasses a broad range of ... | Wikipedia/Geographic_information_system_software |
A mashup (computer industry jargon), in web development, is a web page or web application that uses content from more than one source to create a single new service displayed in a single graphical interface. For example, a user could combine the addresses and photographs of their library branches with a Google map to c... | Wikipedia/Mashup_(web_application_hybrid) |
Animal geography is a subfield of the nature–society/human–environment branch of geography as well as a part of the larger, interdisciplinary umbrella of human–animal studies (HAS). Animal geography is defined as the study of "the complex entanglings of human–animal relations with space, place, location, environment an... | Wikipedia/Animal_geographies |
In information science, an ontology encompasses a representation, formal naming, and definitions of the categories, properties, and relations between the concepts, data, or entities that pertain to one, many, or all domains of discourse. More simply, an ontology is a way of showing the properties of a subject area and ... | Wikipedia/Ontology_(computer_science) |
Oceanography (from Ancient Greek ὠκεανός (ōkeanós) 'ocean' and γραφή (graphḗ) 'writing'), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology.
It is an Earth science, which covers a wide range of topic... | Wikipedia/Oceanography |
Geographic information science (GIScience, GISc) or geoinformation science is a scientific discipline at the crossroads of computational science, social science, and natural science that studies geographic information, including how it represents phenomena in the real world, how it represents the way humans understand ... | Wikipedia/Geographic_information_science |
In geodesy, conversion among different geographic coordinate systems is made necessary by the different geographic coordinate systems in use across the world and over time. Coordinate conversion is composed of a number of different types of conversion: format change of geographic coordinates, conversion of coordinate s... | Wikipedia/Geographic_coordinate_conversion |
Extract, transform, load (ETL) is a three-phase computing process where data is extracted from an input source, transformed (including cleaning), and loaded into an output data container. The data can be collected from one or more sources and it can also be output to one or more destinations. ETL processing is typicall... | Wikipedia/Extract,_transform,_load |
In mathematics, the Fourier transform (FT) is an integral transform that takes a function as input then outputs another function that describes the extent to which various frequencies are present in the original function. The output of the transform is a complex-valued function of frequency. The term Fourier transform ... | Wikipedia/Fourier_transforms |
Land change models (LCMs) describe, project, and explain changes in and the dynamics of land use and land-cover. LCMs are a means of understanding ways that humans change the Earth's surface in the past, present, and future.
Land change models are valuable in development policy, helping guide more appropriate decisions... | Wikipedia/Land_change_modeling |
A geographic coordinate system (GCS) is a spherical or geodetic coordinate system for measuring and communicating positions directly on Earth as latitude and longitude. It is the simplest, oldest, and most widely used type of the various spatial reference systems that are in use, and forms the basis for most others. Al... | Wikipedia/Geographic_coordinate_system |
Geographic information systems (GIS) play a constantly evolving role in geospatial intelligence (GEOINT) and United States national security. These technologies allow a user to efficiently manage, analyze, and produce geospatial data, to combine GEOINT with other forms of intelligence collection, and to perform highly ... | Wikipedia/Geographic_information_systems_in_geospatial_intelligence |
A hydrologic model is a simplification of a real-world system (e.g., surface water, soil water, wetland, groundwater, estuary) that aids in understanding, predicting, and managing water resources. Both the flow and quality of water are commonly studied using hydrologic models.
== Analog models ==
Prior to the advent ... | Wikipedia/Hydrological_model |
Geographic data and information is defined in the ISO/TC 211 series of standards as data and information having an implicit or explicit association with a location relative to Earth (a geographic location or geographic position). It is also called geospatial data and information, georeferenced data and information, as ... | Wikipedia/Geographic_data_and_information |
A historical geographic information system (also written as historical GIS or HGIS) is a geographic information system that may display, store and analyze data of past geographies and track changes in time. It can be regarded as a tool for historical geography.
== Techniques ==
Historical geographic information syste... | Wikipedia/Historical_geographic_information_system |
Cartographic design or map design is the process of crafting the appearance of a map, applying the principles of design and knowledge of how maps are used to create a map that has both aesthetic appeal and practical function. It shares this dual goal with almost all forms of design; it also shares with other design, es... | Wikipedia/Cartographic_design |
Map algebra is an algebra for manipulating geographic data, primarily fields. Developed by Dr. Dana Tomlin and others in the late 1970s, it is a set of primitive operations in a geographic information system (GIS) which allows one or more raster layers ("maps") of similar dimensions to produce a new raster layer (map)... | Wikipedia/Map_algebra |
The Advanced Very-High-Resolution Radiometer (AVHRR) instrument is a space-borne sensor that measures the reflectance of the Earth in five spectral bands that are relatively wide by today's standards. AVHRR instruments are or have been carried by the National Oceanic and Atmospheric Administration (NOAA) family of pola... | Wikipedia/Advanced_very-high-resolution_radiometer |
The Helmert transformation (named after Friedrich Robert Helmert, 1843–1917) is a geometric transformation method within a three-dimensional space.
It is frequently used in geodesy to produce datum transformations between datums.
The Helmert transformation is also called a seven-parameter transformation and is a simi... | Wikipedia/Helmert_transformation |
Quaternary science is the subfield of geology which studies the Quaternary Period commonly known as the ice age. The Quaternary Period is a time period that started around 2.58 million years ago and continues today. This period is divided into two epochs – the Pleistocene Epoch and the Holocene Epoch. The aim of Quate... | Wikipedia/Quaternary_science |
A geographic data model, geospatial geographical measurements, or simply data from modules in the context of geographic information systems (GIS), is a mathematical and digital structure for representing phenomena over the Earth. Generally, such data modules represent various aspects of these phenomena by means of stat... | Wikipedia/Data_model_(GIS) |
Soil science is the study of soil as a natural resource on the surface of the Earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to the use and management of soils.
The main branches of soil science are pedology... | Wikipedia/Soil_science |
Aquatic science is the study of the various bodies of water that make up our planet including oceanic and freshwater environments. Aquatic scientists study the movement of water, the chemistry of water, aquatic organisms, aquatic ecosystems, the movement of materials in and out of aquatic ecosystems, and the use of wat... | Wikipedia/Aquatic_science |
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