In cartography, a map is a representation or abstraction of geographic reality. Maps are used for a wide range of purposes, including navigation, scientific research, governance, and warfare. A common use is route planning, which enables users to find their way to their destination. Specialized maps called charts are used for nautical navigation (nautical charts) and aviation (aeronautical charts). Scientists use maps to organize spatial data in fields such as geology, meteorology, seismology and demographics. Governments use maps for administrative functions such as census, electoral districts, property taxation, dispatching police, and coordinating disaster relief. Military and security organizations use maps for mission planning, surveillance, border management, logistics, and intelligence analysis.
One of the earliest preserved maps is from the Akkadian Empire (in modern Iraq) inscribed on a clay tablet and dated to 2300 BCE. By the 5th century BCE, Greeks were drawing maps of their known world, encompassing the Mediterranean Sea and most of Europe, North Africa, and the Middle East. Maps were important tools in the Age of Discovery, when mariners used them to explore new lands. Applications of cartography expanded in the late 17th century with the development of thematic maps, which portrayed specific kinds of datasuch as rainfall or population densityrather than focusing on geographic features such as rivers, mountains, and cities. The rapid expansion of road networks and mass transit systems in the 20th century created a market for mass-produced maps aimed at the traveling public.
The development of computer cartography and geographic information systems in the mid-20th century enabled the storage of vast amounts of geographic data, which could be dynamically displayed and analyzed. Unlike paper maps, interactive maps let users zoom, pan, and choose which data to view. Geographic data used for mapmaking includes imagery, scanned paper maps, surveying measurements, geographic features, and terrain data.
Designing a map is a complex process involving the selection and arrangement of graphical elements to create a map that is informative, useful, and uncluttered. Because the amount of available geographic data often exceeds what can be effectively displayed, map designers must apply a generalization process to decide which elements to display and which to omit. The amount of detail is influenced by the map scale, expressed as a ratio between a distance on the map and the corresponding distance on the ground. The choice of a map projection is fundamental, as every projection introduces characteristic distortions. Geographic coordinates may be displayed as latitude and longitude, or in a Cartesian (XY grid) system. In addition to geographic data, maps may include supplemental elements such as legends (guides to the map's symbols), scale bars, north arrows, or inset maps.
Definition and etymology
The word "map" first appeared in English around 1527 CE. It originates from the Late Latin word ('napkin, cloth') arising from Classical Latin. Alternatively, it may stem from the French or the Latin (both 'map of the world').
The meaning of "map" depends on the context. In cartography, early definitions focused on representations of the Earth printed on paper, as in the 1938 definition by the cartographer Erwin Raisz (in the first major book on cartography in English): "a conventionalized picture of the Earth's pattern as seen from above, to which lettering is added for identification". The advent of computers and interplanetary exploration in the late 20th century led cartographers to adopt definitions that included media other than paper and depictions of things other than the Earth, as in the brief 1976 definition by the cartographer Arthur H. Robinson: "a graphic representation of the milieu". A 1987 definition by the cartographers 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". Later definitions widened to encompass maps as abstract models, such as the 1992 definition "a representation or abstraction of geographical reality: a tool for presenting geographical information in a way that is visual, digital or tactile".
Outside cartography, "map" is used as an analogy or metaphor in a broad range of contexts. In the 19th century, the New English Dictionary (predecessor to the Oxford English Dictionary) included the definition "circumstantial account of a state of things". The Oxford English Dictionary, , 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 conceptualization or mental representation of the structure, extent, or layout of an area of experience, field of study, or ideology". This article focuses on cartographic maps and does not cover metaphorical or figurative uses.
Applications
Maps support a wide variety of functions. Common applications of maps in everyday life include navigation and route planning: they are useful for finding nearby points of interest such as hospitals, gas stations, hotels, restaurants and parks. People planning vacations or outings often rely on maps to identify destinations, using road maps and tourist maps. Commercial and recreational traffic in the air and on the water uses maps (called "charts" in this context): air traffic relies on aeronautical charts, and water traffic uses nautical charts.
Military and security forces use maps for mission planning, surveillance, border management, and intelligence analysis. Politicians use maps to promote political agendas or propaganda, whether within a nation or in international disputes. In the commercial realm, maps are used for advertising and other persuasive purposes.
Government-related applications include census, elections, administration, and property taxation. Local or regional governments use maps for urban planning, such as designing roads, public transportation, housing developments, and green spaces. Public and private utilities use maps to maintain distribution systems for water, electricity, gas, telecommunications, and sewers. Emergency, fire, and police services use maps for evacuation planning, dispatching fire or police responders, and coordinating disaster relief. Cadastral maps are essential tools for managing real property boundaries, which are required for monitoring construction progress and creating zoning regulations. Governments also use maps to inform policy decisions about voting district boundaries, labor force analysis, utility service planning, social and educational services, poverty analysis, marketing analysis, flood risk, and agriculture.
Environmental protection and management utilize maps to monitor forests, wildlife habitats, climate change, floods, wildfires, and pollution. Foresters, ranchers, and farmers can use maps to manage land, resources, and forests.
Scientists use maps to manage spatial data when studying subjects such as geology, weather, earthquakes, and population distribution. Maps help public health authorities track disease outbreaks, and scientists map genetic patterns in populations.
Educators often use maps as tools when teaching geography, history, environmental science, and spatial thinking.
Journalists frequently use maps in their reporting to help audiences understand the geographic context of stories and events. Maps are sometimes considered things of beauty and displayed as artwork, used as home decorations, or incorporated into a larger work of art.
Digital maps support autonomous navigation and spatial awareness for unmanned aircraft, boats, cars, and robots. These devices can consult a digital map to determine their position (a process called "localization") and to determine a path to their goal. In some applications, unmanned vehicles dynamically create a digital map of their surroundings by exploring their environment; this process is called simultaneous localization and mapping (SLAM).
History
Antiquity to 14th century
It is unknown when or where humans created the first maps. Their appearance in the records of numerous ancient cultures suggests that mapmaking originated in prehistory. 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). Egyptian maps on papyrus from 1300 BCE show the location of gold mines. A document from China dated 1020 BCE describes maps used for town planning. Early Chinese maps that are still preserved include one from the 4th century BCE engraved on a large bronze sheet, showing the location of five mausoleums, and a set of maps drawn on silk from the 2nd century BCE, which showed more sophistication than contemporary maps originating in Europe.
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. One of the most influential early maps was a world map prepared around 150 CE by the Greco-Roman geographer and scientist Ptolemy. Maps created by the Romansin contrast to the Greek emphasis on sciencewere used for political and administrative purposes: in 44 BCE Julius Caesar commissioned a map of the known world, which was prepared by Agrippa. The Romans also produced the Tabula Peutingeriana, which diagrammed most major roads of their empire. Like many modern transit maps, it is schematic in nature and is not drawn to scale.
A notable set of maps from the Islamic world was the Nuzhat al-Mushtaq ('The Book of Pleasant Journeys into Faraway Lands')an atlas created in 1154 by Muhammad al-Idrisi, an Arab geographer, at the request of Norman King Roger II. Within medieval Europe, a large number of ('maps of the world') were created andas Christianity dominated medieval European societymany incorporated religious themes. Scholars refer to some of the as T-O maps because they depicted the Earth as an "O" shape, containing three continents (Europe, Asia, and Africa) separated by waters in a "T" shape.
15th to 19th centuries
Maps played a major role in the Age of Discovery. On his first voyage in 1492, Christopher Columbus carried a world map created by Paolo dal Pozzo Toscanelli. The map did not include the Americas and greatly underestimated the distance from Europe westward to Asia. That year, Martin Behaim created the Erdapfel ()one of the earliest extant globes.
In the 16th century, map accuracy improved with the development of triangulation (initially described by Gemma Frisius in 1533), which advanced surveying techniques by using devices such as plane tables and theodolites to precisely measure angles between lines of sight to landmarks. During this era, cartographers also advanced the study of map projections; notably Gerardus Mercator, who created the Mercator projection in 1569, which proved valuable to navigators because it allowed them to draw a straight line on the map pointing to their destination and reach it by following the indicated compass direction. When Europeans encountered indigenous peoples in Central and South America and in Oceania, they found maps already in use for navigation, administration, and commerce.