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A map is a depiction of interrelationships, commonly spatial, between things within a space.[1] A map may be annotated with text and graphics. Like any graphic, a map may be fixed to paper or other durable media, or may be displayed on a transitory medium such as a computer screen. Some maps change interactively.[2] Although maps are commonly used to depict geographic elements, they may represent any space, real or fictional. The subject being mapped may be two-dimensional such as Earth's surface, three-dimensional such as Earth's interior, or from an abstract space of any dimension.
Maps of geographic territory have a very long tradition and have existed from ancient times. The word "map" comes from the medieval Latin: Mappa mundi, wherein mappa meant 'napkin' or 'cloth' and mundi 'of the world'.[3] Thus, "map" became a shortened term referring to a flat representation of Earth's surface.
Definition and etymology
The word "map" first appeared in English around 1120 CE. It originated either from the Late Latin word mappa ('napkin, cloth') originating in Classical Latin, or from Frenchmappemonde or Latin mappa mundi (both 'map of the world').[4]
The meaning of the word "map" depends on the context.[5][a] Within the realm of cartography, early definitions focused on representations of the Earth printed on paper, as in the 1938 definition by Erwin Raisz (in the first major book on Cartography in the English language[b]) "a conventionalized picture of the Earth's pattern as seen from above, to which lettering is added for identification".[6]
In the 1931 book Science and Sanity, Alfred Korzybski argued that "A map is not the territory it represents, but, if correct, it has a similar structure to the territory, which accounts for its usefulness."[8] This view has been adopted by some cartographers to define a map as a model of reality.[9] This shift in thinking reflects the broad view of scientific cartography being based on Euclidean geometry and Gaussian statistics.[10] During the 1960s and early Quantitative revolution in geography, maps were a central topic of research. William Bunge explored the topic of cartography and maps in his book Theoretical Geography, where in a chapter titled "Metacartography" he defined maps as a subset of mathematics, emphasizing geometry and set theory.[11][12]
In the late 20th century–following the advent of computers and interplanetary exploration–the cartographic community adopted broader definitions which included media other than paper, and depicting things other than the Earth, as in the brief 1976 definition by Arthur H. Robinson "a graphic representation of the milieu".[13] A definition used within the discipline of cartography–created in 1987 by John Brian Harley and David Woodward– is "graphic representations that facilitate a spatial understanding of things, concepts, conditions, processes, or events in the human world".[14]
Outside of cartography, "map" is used as an analogy or metaphor in a broad range of contexts.[15] In the nineteenth century, the New English Dictionary (predecessor to the Oxford English Dictionary) included the definition "circumstantial account of a state of things."[16] The Oxford English Dictionary, as of 2026, includes the primary definition (a representation of the Earth's surface) and also includes "a diagram or collection of data showing the spatial distribution of something or the relative positions of its components" and the figurative meaning "a conceputalization or mental representation of the structure, extent, or layout of an area of experience, field of study, or ideology".[4]
No one knows when or where humans created the first maps, but the desire to preserve and share geographic data is so fundamental to human nature, it is likely that maps were produced very early in human history.[19] One of the earliest preserved maps is inscribed on a clay tablet, dated to 2300 BCE, and found in Nuzi within the Akkadian Empire (in modern Iraq).[20][d] Egyptian maps on papyrus from 1300 BCE show the location of gold mines.[22] A document from China dated 1020 BCE describes maps used for town planning purposes.[23][e] An early Chinese map that is still preserved from about the 4th century BCE, which shows more sophistication than contemporary maps originating in Europe.[24]
Around 490 BCE, Greek geographer Hecataeus created a map of his known world, encompassing the Mediterranean Sea and most of Europe, North Africa, and the Middle East.[25] One of the most influential early maps was a map of the world prepared around 150 CE by the Greco-Roman geographer and scientist Ptolemy.[26] Maps created by the Romans–in contrast to the Greek emphasis on science–were for political and administrative purposes: in 44 BCE Julius Caesar commissioned a map of the known world, which was prepared by Agrippa.[27] The Romans also produced the Tabula Peutingeriana which diagrams most major roads of their empire. Like many modern transit maps, it is schematic in nature and is not drawn to scale.[28][f]
A notable set of maps from the Islamic world was the Nuzhat al-Mushtaq ('The Book of Pleasant Journeys into Faraway Lands')[g]–an atlas created by Arab geographerMuhammad al-Idrisi in 1154, at the request of Norman King Roger II.[18][h] Within Medieval Europe, a large number of mappamundi ('maps of the world') were created,[31] and–as Christianity dominated much of medieval society–many of them incorporated religious themes.[32] Scholars refer to some of these maps as T-O maps because the map depicted the Earth as a circular "O" shape, containing three continents (Europe, Asia, and Africa) separated by waters in a "T" shape.[33][i]
In the 16th century, the accuracy of maps improved with the development of triangulation (initially described by Gemma Frisius in 1533) which improved older surveying techniques by using devices such as plane tables and theodolites to precisely measure angles between landmarks.[39] During this era, cartographers advanced the study of map projections, notably Gerardus Mercator who created the Mercator projection in 1569 which proved valuable to navigators.[38] Humanity's impulse to create maps was illustrated when Europeans encountered indigenous peoples in Central and South America and in Oceania: there they found maps already in use for navigation, administration, and commerce.[40][j]
The applications of cartography expanded in the late 17th century with the invention of thematic maps which portrayed a specific kind of data–such as rainfall or population density–in contrast to simply portraying major geographic features such as rivers, mountains, and cities.[41][k] In the late 18th century, accuracy of maps increased dramatically with the perfection of clocks that could keep accurately time for extended periods while withstanding the violent motions of a ship and the temperature changes of different climates. These chronometers enabled longitude to be computed accurately at any point on Earth.[43] The rise of nationalism in the 19th century was reinforced by maps,[44] as noted by the French historian Christian Jacob[fr] who wrote that maps focused on individual nations were "the visual glue of a sense of national identity".[45]
Military applications led to innovations in cartography. In the late 18th century, Napoleon created a corps of geographic engineers[fr] to produce topographic maps for military use.[46] During WWI, cameras were mounted in airplanes which flew over battlefields and took photographs that were later analyzed for reconnaissance purposes.[47] Some photos were used to update trench maps, at scales up to 1:10,000.[46] After WW I, civilian cartographers used aerial photography in conjunction with the new science of photogrammetry to generate maps more rapidly than was possible with ground-based surveying.[48] In the early 20th century, maps were widely used for propaganda purposes–both to promote territorial claims and to exaggerate threats from perceived enemies.[49][l]
Maps support a large variety of purposes and functions. Perhaps the most common applications of maps in everyday life relate to navigation and route planning. Maps are useful for finding nearby restaurants, hospitals, gas stations, hotels, parks, and other points of interest.[54] People planning vacations or outings often rely on maps to identify destinations, using road maps and tourism-related maps.[55] Commercial and recreational traffic in the air and water use maps (called "charts" in this context): airplane traffic relies on aeronautical charts and water traffic uses nautical charts.[56]
Government-related applications include census, elections, administration, and property taxation.[57] Local or regional governments use maps for urban planning purposes such as designing roads, public transportation, housing developments, and green spaces.[58] Public and private utilities use maps for maintaining distribution systems for water, electricity, gas, telecommunications, and sewer.[59] Emergency, fire, and police services use maps for evacuation planning, dispatching fire or police responders, and coordinating disaster relief.[60]Cadastral maps are an essential tool for managing real property boundaries, which are required for monitoring construction progress, evaluating neighborhood needs and property values, zoning regulations.[61]
Maps are used by military commanders to plan and monitor campaigns, and by historians to document the events. This map is of Operation Typhoon.
Military and security forces use maps for mission planning, surveillance, border management, and intelligence analysis.[62] Politicians use maps to promote political agendas or propaganda: both within a nation or related to international disputes.[63] In the commercial realm, maps are used for advertising or other persuasive purposes.[64]
Environmental protection and management is an area where maps are useful, including monitoring forests and wildlife habitats; monitoring climate change, floods, wildfires, and pollution.[65] Foresters, ranchers and farmers can use maps to manage land and resources, including forest management, precision farming, crop monitoring, irrigation planning, and soil analysis.[citation needed][66]
Scientists from many disciplines use maps to manage spatial data when studying a variety of subjects such as geology, weather, earthquakes, and population distribution.[67] Maps help public health authorities track disease outbreaks, identify healthcare access gaps, and allocate medical resources.[68][citation needed] Educators often use maps as tools when teaching geography, history, environmental science, and spatial thinking.[69]
Journalists frequently use maps as part of their reporting to help audiences understand the geographic context of stories and events.[70] Maps are sometimes considered to be things of beauty and displayed as artwork or home decorations, or incorporated as an element of a larger work of art.[71]
A cartographer must make many choices when designing a map, such as page layout, coverage area, orientation (which compass direction is up), scale, what data to include or–conversely–omit, projection, coordinate system, symbols, shapes, colors, labels, and typography. The choices depend on the purpose of the map and its intended audience.[72]
An important aspect of map design is the layout, which involves arranging the geographic data as well as all auxiliary elements, such as the title, legend, map scale, and insets.[73] Another fundamental choice for many maps is the basemap, which is the background geographic display. Basemaps may be landforms (that depict the terrain), land usage (such as property lines, satellite imagery), or vector-style features (roads, water features, etc).[74].
Coverage area
Maps can be created in a variety of shapes. A common shape is rectangular, but some polar maps are circular in shape.[citation needed]
If a map is rendered on a rectangular 2-dimensional medium, the extent of its coverage will be roughly rectangular.[citation needed] However, when a map covers a large region, such as an entire continent, the coverage on the Earth's surface may not be a true rectangle. If a rectangular map displays coordinate data, its extent can be sometimes be defined by the four coordinate values of the four edges of the map.[75]
The orientation of a map is the geographical direction toward the top of the map.[m] Modern maps generally orient maps north up. If a map has a non-north orientation (such as magnetic north up) the map will usually include a graphical indicator pointing north.[77]
The earliest map with a known orientation is an Akkadian Empire clay tablet with an east up map, circa 2300 BCE.[78] The orientation of ancient Egyptian maps is uncertain, but some may have been oriented south up.[79]
In ancient and Middle Ages Europe, orientation varied, and many maps did not contain an explicit indication of their orientation.[80] The archetypes of the Tabula Peutingeriana and Ptolemy's map probably were north up.[80]Mappamundi were oriented in all four cardinal directions.[81] Many T and O maps, were drawn with east at the top,[82] but some displayed west or south up.[83]
Polar maps of the Arctic or Antarctic regions are conventionally centered on the pole; the direction North would be toward or away from the center of the map, respectively. Typical maps of the Arctic have 0° meridian toward the bottom of the page; maps of the Antarctic have the 0° meridian toward the top of the page.[citation needed]
Although most modern government-produced maps are north up, some maps intended for recreational or tourism use will employ an unusual orientation if the feature being depicted is long and narrow. An example is this National Park Service map of the Blue Ridge Parkway, which is a 755km (469mi) long road that runs diagonally from southwest to northeast. The map's top is to the northeast.[citation needed]
This large scale map has higher resolution and covers a smaller area. This is scan of a paper map printed with a scale of 1:24,000.
This small scale map has lower resolution and covers a larger area. The scale of this digital map varies within the map, but is roughly 1:4,000,000.[n]
The scale of a map is a numerical value that indicates how measurements in the map relate to the reality they depict.[85] Map scales are typically stated as a ratio, such as 1:12,000, which means that every centimeter (cm) on the map represents 12,000 cm (or 120 m) on the ground.[85] Scales can be useful in many contexts, for example, a navigator can measure the distance between two points on a map, and multiply by the scale to obtain an approximate value of the distance between the two points in the world.[85][o]
Maps can be classified as "small scale" (lower resolution, covering large areas) or "large scale" (higher resolution, covering small areas).[87] Although there is no official dividing line between these two terms, 1:500,000 or 1:1,000,000 is sometimes used to partition those terms.[87] In some contexts, a third term–"medium scale"–may be used for maps with scales ranging from about 1:250,000 to 1:1,000,000.[88]
Because map projections introduce some distortion when the earth's surface is flattened onto paper, the scale of a map always varies through the map. For large scale maps that cover a small region, the variations of the scale are generally small, and the scale can often be treated as constant across the map.[89] But for small scale maps that cover large areas like continents or the whole earth, the variations in scale can be large, and the scale should be treated as merely a nominal value.[89][p]
The notion of scale is closely related to the concept of resolution, which is the granularity or precision with which XY locations are measured.[84] For example, assuming one can resolve locations within half a millimeter on a map, that determines the map's resolution. Thus, a 1:10,000 scale map has a resolution of 5 m; and a 1:1,000,000 scale map has a resolution of 500 m.[84] Conversely, a raster image of the earth with each pixel representing 2 km corresponds to a map scale of 1:4,000,000.[84]
Map scales were originally used in the context of paper maps, where the ratio of map-to-reality has an unambiguous definition. But scales can also be applied to digital map databases.[90] Since a database does not have a definitive paper representation, the scale is instead based on the resolution of the database's XY location values. The resolution of a database's XY locations reflects the amount of generalization or decluttering that has been applied to the objects in the database.[91] For example, a database that contains features stored with a 5 m resolution could be considered to have a scale of 1:10,000.[84] Although the geographic data in a database may be visualized at any magnification, it is best displayed at scales ranging from 0.5 to 2.0 times the scale suggested by the database's resolution.[92]
Generalization is the process of reducing the information content in a map so the map more effectively performs its intended purpose.[93] The process for generalizing a particular map depends on the type of map, its scale, and its intended audience.[93] Procedures performed during generalization include selection, simplification, exaggeration, aggregation, smoothing, elimination, and symbolization.[93][q]
The process of generalization is functionally the same for both manually designed maps and interactive digital maps. However, generalization of interactive maps is partially automatically by software applications.[97][r]
The first step in generalization is typically selection, which is simply choosing which types of features to include in the map.[98] Depending on the purpose of the map, the mapmaker may omit, for example, roads, buildings, bodies of water, or towns with a population under 100,000.[99].
Simplification is the process of simplifying a particular feature (such as a river, grove of trees, group of buildings, etc.) by eliminating detail.[100] For example, a grove of eight distinct trees may be replaced by one tree; or a fence defined by 20 straight segments may be reduced to five segments.[100] The degree of simplification depends on how many features should appear on the final map, and how densely they should be placed.[101][s]
The process of exaggeration involves enlarging some aspect of an object to better convey the object's real-world essence.[102]Aggregation is grouping several distinct objects together into one. Examples are grouping multiple point objects into one; or multiple point objects into an areal object; or multiple areal objects into one.[103]Smoothing a line or perimeter involves replacing the line with a smoother version that captures the essence of the line while eliminating jagged, fine-scale features.[104][t]Symbolization is the process of choosing a graphical depiction to represent each real-world object. Selecting the graphical attributes of the depictions–including shape, color, size, and pattern–is an important part of the symbolization process.[106][u]
Maps visually depict the location and properties of some geographic features using map symbols, which are graphical depictions composed of several visual variables, such as size, shape, color, and pattern.[108]
The various features shown on a map are represented by conventional signs or symbols.[citation needed] For example, colors can be used to indicate a classification of roads. Those signs are usually explained in a map legend on the margin of the map, or on a separately published characteristic sheet.[109]
A projection is an algorithm that transforms all or part of the Earth's surface[v] into a 2-dimensional representation.[111] There are dozens of projections that mapmakers may choose from when creating a map.[112] All projections introduce some distortions into the representation because it is impossible to force a spheroidal surface into a flat shape without tearing or stretching it.[113]
Some projections preserve important characteristics of the spheroidal surface. Equal-area projections preserve the areas of countries or regions.[114][115]Conformal projections preserve the angles between intersecting lines, and give the impression that shapes are approximately preserved.[114][116]Equidistant projections preserve distances between one or two specific points to all other points.[114][117] Some projections try to balance these goals, without perfectly achieving any one of them;[118] a notable example is the Robinson projection.[119]
A controversial projection is Web Mercator–a variant of the standard Mercator projection–which was adopted by Google around 2005 for use in their online zoomable global map.[122] The projection has been criticized for its large distortions in the higher latitudes, as well as for inaccuracies in coordinates when zoomed-in.[123][w]
Maps that display elevations of land or objects must use a vertical datum as the baseline for that measurement. Ellipsoids, such as the one shown, can be used as a vertical datum.
When a map displays coordinates of places and objects, the mapmaker must select a coordinate system, called the geodetic datum. Typically, one coordinate system (called the horizontal datum) is used for horizontal (XY) coordinates, and another (called the vertical datum) for vertical (Z) coordinates.[125]
Vertical datums are baselines used to measure an object's Z location (height). Vertical datums include ellipsoids and the geoid. An ellipsoid, such as WGS84, is an imaginary spheroid that approximates the earth's surface. A geoid is shape the world's oceans would take under the influence of Earth's gravity and rotation alone, without winds or tides; the geoid is not a smooth spheroid, but has bumps due to the way earth's varying density influences gravity.[citation needed]
Many nations have national mapping agencies that define projected coordinate systems to be used for maps that cover the country.[128] These coordinate systems usually use an XY Cartesian system for horizontal locations (rather than latitude/longitude).[citation needed] Thus, horizontal locations are typcially measured in meters (or, in US, feet).[citation needed] A nation may have many such coordinate systems, each tailored for a specific province, state, or region. For example, the US defines 125 coordinate systems that cover the country, called the "state plane" systems.[128]
Colors and patterns
Use of colors in maps
This map uses both color (hue) and pattern (hatching) to distinguish regions.
This thematic map uses a single hue and varies the lightness to distinguish regions.
Colors can play an important role in map design.[129] A map produced with a single color can confuse readers since every line and object is the same color; even a small amount of color can significantly improve the readability of map.[130] Any color may be characterized by a particular combination of three independent attributes: hue, lightness, and saturation.[131] Of those attributes, hue is generally used to indicate important distinctions within a map.[132] Some maps use hue conventions such as: blue for water; green for vegetation; yellow or tan for arid regions; and brown for topographic contour lines.[133] Lightness or tint can also be used to distinguish features in a map,[134] particularly for progressively coloring regions in a quantitative map.[135]
In maps, patterns are repeating design motifs that fill areas and convey information to the user.[136] The patterns may consist of lines, dots, pictographs, or hatching.[137] For example, patterns may be used to distinguish biomes such as swamp, desert, or forest. The International Geographical Union published a set of patterns to be utilized to designate soil types, including patterns for mud, clay, sandstone, and gravel.[138] Colors and patterns may be used in combination within a single area.[129]
This map from a 1919 book on lettering provides guidance on placing hand-written text on a map.[139]
Many maps include textual labels that identify features. The design and layout of the text has a major influence on the overall graphical quality of the map.[140] Maps often use multiple fonts and typefaces on a map in order to convey information to the user. For example, a map may use italic, boldface, or various sizes of lettering to indicate water features vs land features, or to designate the size of city or town.[141] Positioning textual labels in a manner that is helpful and attractive is a difficult, but important process.[142] Positioning can be performed manually by a cartographer, or automatically by software algorithms.[143] Positioning guidelines that are sometimes used include:[144]
Text should be aligned horizontally, although in large maps covering the whole earth or large regions (called "small scale" maps), the text may instead be aligned along lines of latitude is acceptable
Text should generally be in a straight line, not curved. Exception: when aligning text along lines of latitude on a small-scale map
When text and graphical objects (such as lines) interfere, the text has priority and the graphic should be interrupted
A name should be entirely on land or on water, but not straddle both
Labels of point features should be offset in a consistent manner, for example, above and slightly to the side of the feature[145]
Auxiliary elements
This map positions the legend in the lower-left; the publisher, title, and scale bar in the upper left; and four insets on the right.
Mythical creatures were sometimes depicted in maps, such as this sea serpent (lower right) in the Carta marina (1539).
Maps often contain a variety of elements or marginalia that supplement the primary geographical imagery.[146] A map scale is often indicated on a map, either textually or as a graphical scale bar. Many maps, particularly if their orientation is not north up, include an orientation indicator which points north..[147] Titles are displayed in many maps, although some maps do not need a title and omit it.[148]
Legends are a critical component of many maps, because they provide the user with essential keys to understanding the map. Legends define graphical symbols and can explain the origin, context, and meaning of the map's thematic data.[149]
Some maps contain smaller maps, called "insets". The insets can serve a variety of purposes, such as showing the location of the primary map in global context[150] or to show high-detail maps of points-of-interest;[citation needed] or to show islands that are relevant to the primary map, but far away.[citation needed]
A cartouche is a ornamental symbol–sometimes very elaborate–found on some maps which contains map marginalia such as the title or author's name. [151] Some globes display an analemma–a figure-eight shaped line–that shows the locations on the earth where the sun is directly overhead throughout the year.[152]
This qualitative map divides Australia in to discrete climate zones.
A thematic map is a special purpose map that depicts a single kind of information. Examples include precipitation maps, population density maps, and pollution maps.[155] In contrast to thematic maps, general reference maps display a variety of information about a region, such as cities, highways, railways, and bodies of water.[155] Many maps have characteristics of both thematic maps and general reference maps, so these two map kinds are not mutually exclusive.[156]
Quantitative and qualitative
Some maps may be classified as quantitative or qualitative. A quantitative map displays the magnitude of a single numerical datum, such as air pressure, population density, or poverty rate. A qualitative map depicts data that can be categorized as two or more kinds, such as a climate map that divides the region into 15 different climate zones; or a map that divides the region based on 20 different religious affiliations.[157]Kenneth Field limits the quantitative/qualitative distinction to thematic maps, but others apply the distinction to any maps that display numerical or statistical data.[157]
Classified by medium
Maps can be classified by the medium in which the are presented, such as paper map, atlas, globe, or digital. Prior to the 21st century, the vast majority of maps were printed on paper.[citation needed] An atlas is collection of maps, usually bound in book form.[158]Globes are 3-dimensional models of the earth (or moon or another planet).[159] A digital map is a map stored in digital form and typically displayed on an electronic visual display such as a computer monitor or smart phone. The electronic display may depict a 2-dimensional map (for example, Google Map or Apple Maps apps), or a 3-dimensional globe (such as Google Earth app).[citation needed][160]
An atlas is a collection of maps, usually in book form.
A globe does not have the distortion inherent in flat maps.
Maps of planets, moons, asteroids, and comet nuclei have been created by astronomers since telescopes were invented.[161] Early extraterrestrial maps were drawn for objects that are relatively large when viewed in a telescope, such as Mercury, Mars, and the Moon.[162] Maps of the Moon played an important role in the space race during the 1960s and 1970s, including the Apollo program which landed the first humans on the Moon.[163][y] Some extraterrestrial objects–such as the Sun and gas planets like Jupiter–do not have solid surfaces. Despite that, they have been mapped to depict their appearance at certain points in time.[162] Some asteroids and comet nuclei have shapes that are so irregular that conventional map projections (designed for spheroidal objects) are not sufficient. Maps for these objects required the invention of novel map projections.[164]
This conventional map emphasizes accurate geography
A topological map is map that emphasizes graphical simplicity, and makes little or no effort to accurately represent geographical distances or locations.[165][z] The term "topological" emphasizes that these maps retain topological relationships in the mathematical sense; thus, all connections between objects are preserved.[167]
Topological maps are sometimes called "schematic maps" because of their diagrammatic nature: their graphical depictions promote comprehension by sacrificing geographic accuracy.[168][aa]
An early schematic map was Tabula Peutingeriana (archetype 4th century[169])–a visual itinerarium that aided travelers by depicting roads and towns, while disregarding geographic accuracy.[170] A notable modern topological map is the official London Underground map.[171][ab][ac] Some cartograms may be considered to be topological maps because they deliberately distort regions so the area of each region represents the value of some data: geographic accuracy is sacrificed to improve comprehension (a sample cartogram is shown below).[173]
Topographic and planimetric
This topographic map displays elevation data as brown contour lines, buildings as black rectangles, forests as green-colored regions, and rivers in blue.
Planimetric maps–in contrast to topographic maps–do not include height information; rather, they display horizontal location information only.[174]
Many topographic maps are general reference maps, because–in addition to elevation–they may display a variety of features such as buildings, bodies of water, vegetation, roads, towns, and railways.[176] Some national mapping agencies produce topographic maps of their country's lands–including the UK's Ordnance Survey and the US's USGS.[177] Many government produced maps are fairly detailed (large scale).[citation needed] Some nations produce two or more series of topographic maps, each at a unique scale. For example, in the UK, topographic maps are produced at four scales: 1:1,250 (urban areas), 1:2,500 (rural areas), 1:10,000 (mountain and moorland areas), and 1:50,000 (the baseline series).[178][ae]
The IDRISI app is a geographic information system app that analyzes spatial geographic data.[af]
OpenStreetMap is an open map database that can be viewed and edited via web browsers and other apps.
An interactive map is a dynamic display of geographic data on an electronic visual display that permits a user to view and explore the data by directly interacting with a map.[179] The interactions may include selecting which kinds of features to display, locating additional data related to individual objects, and adjusting the map scale.[180] Interactive maps can also display all or part of the earth as a globe, with no map projection applied.[181]
.[182]
Interactive maps are often used, especially on mobile devices, to provide location-based services to users, such as providing navigation directions.[183] Interactive maps may provide the ability for users to update shared geographic data, enabling a form of crowdsourcing.[184]
Geographic data displayed by an interactive map is generally stored in a database. Online map services such as Apple Maps stores the database on a server, and the user ("client") fetches the data dynamically. Alternatively, the data may be stored locally, for example, if a municipality has their own GIS which stores cadastral or utility data; or a military or police organization with a secure geographic database.[185]
This cartogram was published in 1916 to emphasize the size and extent of the British Empire. The area of each country is proportional to its population.[192]The Mercator projection greatly distorts the size of countries.
All maps are selective representations of reality and cannot depict it with complete accuracy. As a result, every map contains some degree of inaccuracy, distortion, or omission.[193] In some cases, these inaccuracies are introduced intentionally; in other cases, they are an inherent consequence of the fact that maps simplify and symbolize reality.[193] Situations where mapmakers deliberately try to mislead the audience include advertising, development planning, military disinformation campaigns, and political propaganda.[194] Cartographer Mark Monmonier suggests that all maps should be treated with a "healthy skepticism" because they reflect editorial and content choices made by their creators.[195]
Some map projections can significantly misrepresent the relative size of countries, particularly in world maps. In the 1970s, the historian Arno Peters asserted that the widespread use of the Mercator projection was "cartographic imperialism", as it showed European countries relatively enlarged compared to developing countries–especially in Africa–nearer to the equator. Arno presented the Gall-Peters projection–an equal-area projection–as a more equitable alternative.[196][ag]
In 1985 politician Shridath Ramphal appealed to geographers to combat bias implicit in maps, particularly related to the north up orientation and the implication that northern countries are superior.[198][ah]
An example of misinformation that is deliberately inserted into a map is a copyright trap, which is a fictional object or place inserted into a map (in an unobtrusive manner) by the mapmaker, that will help them detect unauthorized copies.[199]
Boundary disputes
Maps can play a role in boundary disputes between nations; as tools for a nation to advocate for their claim, and as evidence in negotiations.[200] With the advent of interactive online maps, countries involved in disputes will often instruct data providers, such as Google Maps, to display a particular boundary line.[201] Google Maps has responded to such demands by storing two versions of the disputed boundary, and choosing the version to display based on the location of the requestor.[201]
Examples of boundary disputes that have led nations to instruct map providers to display a particular boundary line include: Russia and Ukraine,[202] India and China,[201][203] Pakistan and India,[204] Turkey and the cultural region of Kurdistan,[205] Cambodia and Thailand,[201] and Vietnam and China's maritime boundary dispute in the South China Sea.[201]
↑This map of the world is a mid-15th century Florentine map based on 13th century translations of Ptolemy's 2nd-century book Geography.
↑Maps are also found on Babylonian clay tables ranging between 2000 and 600 BCE, including one that may be considered the first map of a culture's known world.[21]
↑The maps from 1020 BCE are not found, only mention of them.
↑The exact date of the Tabula Peutingeriana is uncertain, but it may have been created around 350 CE.[29]
↑Full Arabic title is Nuzhat al-mushtāq fī ikhtirāq al-āfāq.[30]
↑Although the circular nature of T-O maps might suggest that the creators believed the Earth was flat, many medieval scholars–including proponent of the T-O design Isidore of Seville–knew the Earth was round.[34]
↑Early thematic weather maps were created by Edmund Halley around 1686.[42]
↑Using maps for propaganda purposes is sometimes described as "persuasive cartography" or "cartographic propaganda".
↑The word "orientation" traces its origin to the belief of primitive people's that the eastern direction was the basis for spatial organization.[76]
↑ The scale of this map varies throughout the map. The pixel length in the north-south direction is approximately 2 km (4,000 pixels and 8,000 km) A resolution of 2 km per pixel corresponds to map scale of roughly 1:4,000,000,[84] although the it depends on how the map is rendered and other factors. All values are approximate.
↑Map scales generally indicate the ratio of distances between objects, not the ratio of areas of objects. Some maps define an "area scale" value for the purpose of relating map areas to real-world areas.[86]
↑When using a map scale in a small scale (large area) map to convert a distance on a map to a real-world distance, the error might be large. In addition, the scale a any single point may differ greatly in the north-south direction vs the east-west direction.
↑Generalization processes named by various cartographic authorities (order not significant):
Robinson 1995–Selection, classification, simplification, exaggeration, and induction.[94]
Field 2018–Selection, amalgamation, exaggeration, displacement, refinement, simplifcation, aggregation, typification, smoothing, enhancing, collapsing, and merging.[95]
↑Some interactive maps may enable the user to select or filter the data that is visualized, which is a form of generalization.
↑A rule of thumb for simplification is: where nc is the number of items on the produced map; ns is the number of items in the source data (covering the same region; the source may be a map or database); sc is the map scale of the produced map; and ss is the scale of the source data.[101]
↑Elimination is a process similar to smoothing: elimination simplifies a line or perimeter by deleting some vertices from the line.[105]
↑"Symbolization"–which is a process used to create every type of graphical marking on a map–should not be confused with "symbols", which are graphical icons, pictograms, or shapes that are designed to present qualitative and quantitative data in a compact manner.[107]
↑Or the surface of any object being mapped, such as the Moon.
↑The NGA US government mapping agency disapproves of the Web Mercator projection, writing: "NGA does not endorse nor does NGA support the spherical based Web Mercator
map projection (and variant namings such as WGS 84 Web Mercator) for the acquisition,
visualization, exploitation, and exchange of any GEOINT data for the NSG."[124]
↑The study of mapping the Moon is called selenography.
↑Topological maps not are not restricted to the field of cartography; they are commonly used in robotics as well.[166]
↑The terms "topological map" and "schematic map" are both used in the field of cartography, with roughly the same meaning. The term "schematic" is used to refer to maps in Robinson 1995 p. 534; Monmonier 2015 pp. 252, 1622; and in Kent & Vujakovic 2017 pp. 450–460. The term "topological" is used to refer to maps in Monmonier 2015 p. 790. Robinson 1995 does not use the term "topological map" (but does mention topological properties of data). Monmonier 2015 also uses "semitopological" to indicate that some effort was made to preserve geographical accuracy.
↑The UK's high-detail 1:1,250 and 1:2,500 maps are only created for select regions; whereas the 1:50,000 baseline series covers the entire country.[citation needed]
↑Peters' favored projection, the Gall-Peters projection, is not considered to be a useful projection by some cartographers, as it depicts Africa (and other regions) as too narrow. Peters' campaign to move away from the Mercator projection was partly successful, and organizations such as the United Nations began using alternative projections.[197]
↑Australian Stuart McArthur created a south up world map in 1979 which placed Australia in a position of prominence. The map was titled "McArthur's Universal Corrective Map of the World".
↑Korzybski, Alfred (1994). Science and Sanity (5ed.). Institute of General Semantics. p.54. ISBN0937298018.
↑Batty, Michael (2019). "A map is not the territory, or is it?". Environment and Planning B: Urban Analytics and City Science. 46 (5). doi:10.1177/2399808319850652.
↑Goodchild, Michael F (2008). "2 Theoretical Geography (1962): William Bunge". In Hubbard, Phil; Kitchin, Rob; Valentine, Gill (eds.). Key Texts in Human Geography. SAGE Publications Ltd. pp.9–16. ISBN978-1412922616. Retrieved 18 March 2025.
↑Monmonier 2015, pp.239–245, 884–951, 951–977, 1696–1700, 1770–1775, 1775–1779, §§ "Cold War", "Military Mapping by Major Powers", "Military Mapping of Geographic Areas", "Warfare and Cartography", "World War I", "World War II".
↑Monmonier 2015, pp.251–255, 539–548, 1766–1770, §§ "Colonial and Imperial Cartography", "Geopolitics and Cartography", "World Revolution and Cartography".
Monmonier 2015, pp.251–255, 413–416, 1099–1100, 1179–1181, 1232–1237, §§ "Colonial and Imperial Cartography", "Eurocentric bias", "Peters Projection", "Cultural and Social Significance of Map Projections", "Race, Maps and the Social Construction of".
Wigen, Kären (2020). Time in maps: from the Age of Discovery to our digital era. David Rumsey Map Center. Chicago: The University of Chicago Press. ISBN9780226718590.