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{{dablink|For other uses, see [[Map (disambiguation)]].  For the acronyms, see [[MAP]] and [[MAPS]]}}
{{dablink|For other uses, see [[Map (disambiguation)]].  For the acronyms, see [[MAP]] and [[MAPS]]}}


A '''map''' is a simplified depiction of a [[space]] which highlights relations between components ([[objects]], regions) of that space.  Most usually a map is a [[2D geometric model|two-dimensional, geometrically accurate representation]] of a [[three-dimensional space]]; e.g., a [[geographical map]]. More generally, maps can be devised to represent any local property of the world or part of it, or any other space, such as the brain (see [[Brain mapping]]).
A '''map''' is a simplified depiction of a [[space]] which highlights relations between components ([[objects]], regions) of that space.  Most usually a map is a [[2D geometric model|two-dimensional, geometrically accurate representation]] of a [[three-dimensional space]]; e.g., a [[geographical map]]. More generally, maps can be devised to represent any local property of the world or part of it, or any other space, such as the brain (see Brain mapping).


==Geographical maps==
== Geographical maps ==
[[Image:Starmap1600.jpg|thumb|200 px|A celestial map from the 17th century, by the Dutch cartographer Frederik de Wit.]]
[[Image:Starmap1600.jpg|thumb|200 px|A celestial map from the 17th century, by the Dutch cartographer Frederik de Wit.]]
The science and art of ''map-making'' is [[cartography]]; see that page for further discussion of the [[History of cartography|history of maps and map-making]].  
The science and art of ''map-making'' is cartography; see that page for further discussion of the [[History of cartography|history of maps and map-making]].  


Map-making dates back to the [[Stone Age]] and appears to predate written language by several millennia. One of the oldest surviving maps is painted on a wall of the [[Catal Huyuk]] settlement in south-central [[Anatolia]] (now [[Turkey]]); it dates from about [[7th millennium BC|6200 BC]]. <ref>*[[Miles Harvey]], ''The Island of Lost Maps: A True Story of Cartographic Crime''. New York : [[Random House]], 2000 ISBN 0-7679-0826-0, cited above; also ISBN 0-375-50151-7 </ref>  One who makes maps professionally or privately is called a cartographer.
Map-making dates back to the Stone Age and appears to predate written language by several millennia. One of the oldest surviving maps is painted on a wall of the [[Catal Huyuk]] settlement in south-central [[Anatolia]] (now Turkey); it dates from about [[7th millennium BC|6200 BC]]. <ref>*[[Miles Harvey]], ''The Island of Lost Maps: A True Story of Cartographic Crime''. New York : [[Random House]], 2000 ISBN 0-7679-0826-0, cited above; also ISBN 0-375-50151-7 </ref>  One who makes maps professionally or privately is called a cartographer.


While we tend to think of maps today as products of a rationalistic, scientific world-view, maps also have a mythic quality. Pre-modern maps, and mapping traditions outside the Western tradition, often merge geography with non-scientific [[cosmography]], showing the relationship of the viewer to the universe. Medieval [[T-O map|"T-O" maps]], for example, show [[Jerusalem]] at the centre of the world, and in some cases related the "body" of the Earth to the body of Christ. By contrast, navigational (or "Portolan") charts of the Mediterranean from the same period are remarkably accurate.  Even today, maps can be powerful rhetorical tools beyond their purely practical value, and this has been the source of much fruitful map criticism over the last twenty years, notably in the works of J.B. Harley, [[Mark Monmonier]], and [[Denis Wood]].
While we tend to think of maps today as products of a rationalistic, scientific world-view, maps also have a mythic quality. Pre-modern maps, and mapping traditions outside the Western tradition, often merge geography with non-scientific [[cosmography]], showing the relationship of the viewer to the universe. Medieval [[T-O map|"T-O" maps]], for example, show Jerusalem at the centre of the world, and in some cases related the "body" of the Earth to the body of Christ. By contrast, navigational (or "Portolan") charts of the Mediterranean from the same period are remarkably accurate.  Even today, maps can be powerful rhetorical tools beyond their purely practical value, and this has been the source of much fruitful map criticism over the last twenty years, notably in the works of J.B. Harley, [[Mark Monmonier]], and [[Denis Wood]].


[[Image:Physical_world.jpg|thumb|333px|right|Physical map of the [[Earth]].]]
[[Image:Physical_world.jpg|thumb|333px|right|Physical map of the Earth.]]


Geographic maps are abstract representations of the world.  It is, of course, this abstraction that makes them useful.  [[Lewis Carroll]] made this point humorously in ''Sylvie and Bruno'' with his mention of a fictional map that had "the scale of a mile to the mile".  A character notes some practical difficulties with this map and states that "we now use the country itself, as its own map, and I assure you it does nearly as well".  This concept is elaborated in a one-paragraph story by [[Jorge Luis Borges]], generally known in [[English language|English]] as "[[On Exactitude in Science]]".
Geographic maps are abstract representations of the world.  It is, of course, this abstraction that makes them useful.  [[Lewis Carroll]] made this point humorously in ''Sylvie and Bruno'' with his mention of a fictional map that had "the scale of a mile to the mile".  A character notes some practical difficulties with this map and states that "we now use the country itself, as its own map, and I assure you it does nearly as well".  This concept is elaborated in a one-paragraph story by Jorge Luis Borges, generally known in English as "[[On Exactitude in Science]]".


Road maps are perhaps the most widely used maps today, and form a subset of navigational maps, which also include aeronautical and [[nautical chart]]s, railroad network maps, and hiking and bicycling maps. In terms of quantity, the largest number of drawn map sheets is probably made up by local surveys, carried out by [[municipality|municipalities]], utilities, tax assessors, emergency services providers, and other local agencies.  Many national surveying projects have been carried out by the military, such as the [[United Kingdom|British]] [[Ordnance Survey]] (now a civilian government agency internationally renowned for its comprehensively detailed work).
Road maps are perhaps the most widely used maps today, and form a subset of navigational maps, which also include aeronautical and nautical charts, railroad network maps, and hiking and bicycling maps. In terms of quantity, the largest number of drawn map sheets is probably made up by local surveys, carried out by municipalities, utilities, tax assessors, emergency services providers, and other local agencies.  Many national surveying projects have been carried out by the military, such as the British [[Ordnance Survey]] (now a civilian government agency internationally renowned for its comprehensively detailed work).


==Orientation of maps==
== Orientation of maps ==
[[Image:Hereford_Mappa_Mundi_1300.jpg|thumb|right|200px|''The [[Hereford Mappa Mundi]]'', about 1300, [[Hereford Cathedral]], England. A classic "T-O" map with Jerusalem at centre, east toward the top, Europe the bottom left and Africa on the right.]]
[[Image:Hereford_Mappa_Mundi_1300.jpg|thumb|right|200px|''The [[Hereford Mappa Mundi]]'', about 1300, [[Hereford Cathedral]], England. A classic "T-O" map with Jerusalem at centre, east toward the top, Europe the bottom left and Africa on the right.]]


The most common cartographic convention is that [[North]] is at the top of a map. This is far from universal, however:
The most common cartographic convention is that [[North]] is at the top of a map. This is far from universal, however:


*[[Polar map]]s of the [[Arctic]] or [[Antarctic]] regions are conventionally centered on the pole, making "north is up" meaningless.
*Polar maps of the Arctic or [[Antarctic]] regions are conventionally centered on the pole, making "north is up" meaningless.
*Azimuthal or Gnomonic projections are often used in planning air routes, centered on specific origin points.  
*Azimuthal or Gnomonic projections are often used in planning air routes, centered on specific origin points.  
*[[Richard Edes Harrison]] produced a striking series of maps during and after [[World War II]] for [[Fortune magazine]]. These used "bird's eye" projections to emphasize globally strategic "fronts" in the air age, pointing out proximities and barriers not as apparent on a conventional  rectangular projection of the world.
*[[Richard Edes Harrison]] produced a striking series of maps during and after World War II for [[Fortune magazine]]. These used "bird's eye" projections to emphasize globally strategic "fronts" in the air age, pointing out proximities and barriers not as apparent on a conventional  rectangular projection of the world.
*[[Buckminster Fuller]]'s [[Dymaxion map]]s are based on a projection of the Earth's sphere onto an [[icosahedron]]. The resulting triangular pieces may be arranged in any order or orientation.
*[[Buckminster Fuller]]'s [[Dymaxion map]]s are based on a projection of the Earth's sphere onto an [[icosahedron]]. The resulting triangular pieces may be arranged in any order or orientation.
*Maps from non-Western traditions are oriented a variety of ways. Old maps of [[Edo]] show the [[Kokyo|Japanese imperial palace]] as the "top," but also at the centre, of the map. Labels on the map are oriented in such a way that you cannot read them properly unless you put the imperial palace above your head.
*Maps from non-Western traditions are oriented a variety of ways. Old maps of [[Edo]] show the [[Kokyo|Japanese imperial palace]] as the "top," but also at the centre, of the map. Labels on the map are oriented in such a way that you cannot read them properly unless you put the imperial palace above your head.
*[[Medieval]] European [[T and O map]]s such as the [[Hereford Mappa Mundi]] were centred on [[Jerusalem]] with east at the top. Indeed, prior to the reintroduction of [[Ptolemy]]'s ''Geography'' to Europe around 1400, there was no single convention in the West. [[Portolan charts]], for example, are oriented to the shores they describe.
*[[Medieval]] European [[T and O map]]s such as the [[Hereford Mappa Mundi]] were centred on Jerusalem with east at the top. Indeed, prior to the reintroduction of [[Ptolemy]]'s ''Geography'' to Europe around 1400, there was no single convention in the West. [[Portolan charts]], for example, are oriented to the shores they describe.
*Route and channel maps have traditionally been oriented to the road or waterway they describe.
*Route and channel maps have traditionally been oriented to the road or waterway they describe.


==Scale and accuracy==
== Scale and accuracy ==
Many but not all maps are drawn to a [[Scale (map)|scale]], allowing the reader to infer the actual sizes of, and distances between, depicted objects.  A larger scale shows more detail, thus requiring a larger map to show the same area.  For example, maps designed for the hiker are often scaled at the [[ratio]] 1:24,000, meaning that 1 of any unit of measurement on the map corresponds to 24,000 of that same unit in reality; while maps designed for the [[motorist]] are often scaled at 1:250,000.  Maps which use some quality other than physical area to determine relative size are called [[cartogram]]s.
Many but not all maps are drawn to a [[Scale (map)|scale]], allowing the reader to infer the actual sizes of, and distances between, depicted objects.  A larger scale shows more detail, thus requiring a larger map to show the same area.  For example, maps designed for the hiker are often scaled at the [[ratio]] 1:24,000, meaning that 1 of any unit of measurement on the map corresponds to 24,000 of that same unit in reality; while maps designed for the [[motorist]] are often scaled at 1:250,000.  Maps which use some quality other than physical area to determine relative size are called [[cartogram]]s.


A famous example of a map without scale is the [[Tube map|London Underground map]], which best fulfils its purpose by being less physically accurate and more visually communicative to the hurried glance of the commuter.  This is not a cartogram (since there is no consistent measure of distance) but a [[Topology|topological]] map that also depicts approximate bearings.  The simple maps shown on some directional [[road sign]]s are further examples of this kind.
A famous example of a map without scale is the [[Tube map|London Underground map]], which best fulfils its purpose by being less physically accurate and more visually communicative to the hurried glance of the commuter.  This is not a cartogram (since there is no consistent measure of distance) but a topological map that also depicts approximate bearings.  The simple maps shown on some directional [[road sign]]s are further examples of this kind.


In fact, most commercial navigational maps, such as road maps and town plans, sacrifice an amount of accuracy in scale to deliver a greater visual usefulness to its user, for example by exaggerating the width of roads.  With the [[end-user]] similarly in mind, cartographers will censor the content of the space depicted by a map in order to provide a useful tool for that user.
In fact, most commercial navigational maps, such as road maps and town plans, sacrifice an amount of accuracy in scale to deliver a greater visual usefulness to its user, for example by exaggerating the width of roads.  With the [[end-user]] similarly in mind, cartographers will censor the content of the space depicted by a map in order to provide a useful tool for that user.
For example, a road map may or may not show [[railroad]]s, and if it does, it may show them less clearly than [[highway]]s.
For example, a road map may or may not show railroads, and if it does, it may show them less clearly than [[highway]]s.


Some maps such as [[topographical map]]s show constant values such as [[average temperature]], these are often represented, along with other characteristics, depending on the scale of the map, in the form of [[Isolines]]. Isolines are often on a map or chart along which there is constant value ([[temperature]], [[pressure]], or [[rainfall]]).
Some maps such as [[topographical map]]s show constant values such as [[average temperature]], these are often represented, along with other characteristics, depending on the scale of the map, in the form of [[Isolines]]. Isolines are often on a map or chart along which there is constant value (temperature, pressure, or [[rainfall]]).


==World maps and projections==
== World maps and projections ==
{{main|World map}}
{{main|World map}}
[[Image:Ocean_gravity_map.gif|right|thumb|200px|Map of large underwater features. (1995, [[NOAA]])]]
[[Image:Ocean_gravity_map.gif|right|thumb|200px|Map of large underwater features. (1995, [[NOAA]])]]
Maps of the world or large areas are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical is to show features of [[geography]] such as mountains, soil type or land use. Geological maps show not only the physical surface, but characteristics of the underlying rock, [[Geologic fault|fault]] lines, and subsurface structures.  
Maps of the world or large areas are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical is to show features of geography such as mountains, soil type or land use. Geological maps show not only the physical surface, but characteristics of the underlying rock, [[Geologic fault|fault]] lines, and subsurface structures.  


Maps that depict the surface of the Earth also use a [[map projection|projection]], a way of translating the three-dimensional real surface of the [[geoid]] to a two-dimensional picture. Perhaps the best-known world-map projection is the [[Mercator Projection]], originally designed as a form of [[nautical chart]].
Maps that depict the surface of the Earth also use a [[map projection|projection]], a way of translating the three-dimensional real surface of the [[geoid]] to a two-dimensional picture. Perhaps the best-known world-map projection is the [[Mercator Projection]], originally designed as a form of nautical chart.


Airplane pilots use aeronautical charts based on a [[Lambert conformal conic projection]], in which a cone is laid over the section of the earth to be mapped. The cone intersects the sphere (the earth) at one or two parallels which are chosen as standard lines. This allows the pilots to plot a great-circle route approximation on a flat, two-dimensional chart.
Airplane pilots use aeronautical charts based on a [[Lambert conformal conic projection]], in which a cone is laid over the section of the earth to be mapped. The cone intersects the sphere (the earth) at one or two parallels which are chosen as standard lines. This allows the pilots to plot a great-circle route approximation on a flat, two-dimensional chart.


==Electronic maps==
== Electronic maps ==
[[Image:Topographic_map_example.png|thumb|200px|A [[USGS]] [[digital raster graphic]].]]
[[Image:Topographic_map_example.png|thumb|200px|A [[USGS]] [[digital raster graphic]].]]
From the last quarter of the 20th century, the indispensable tool of the cartographer has been the computer. Much of cartography, especially at the data-gathering survey level, has been subsumed by [[geographic information system|Geographic Information Systems]] (GIS).  The functionality of maps has been greatly advanced by technology allowing, for example, the superimposition of spatially located variables onto existing geographical maps. Having local information such as rainfall level, distribution of wildlife, or demographic data integrated within the map makes for more efficient analysis and better decision making. In the pre-electronic age such superimposition of data led to [[John Snow (physician)|Dr. John Snow]] discovering the cause of cholera. Today, it is used by agencies as diverse as wildlife conservationists and militaries around the world.
From the last quarter of the 20th century, the indispensable tool of the cartographer has been the computer. Much of cartography, especially at the data-gathering survey level, has been subsumed by Geographic Information Systems (GIS).  The functionality of maps has been greatly advanced by technology allowing, for example, the superimposition of spatially located variables onto existing geographical maps. Having local information such as rainfall level, distribution of wildlife, or demographic data integrated within the map makes for more efficient analysis and better decision making. In the pre-electronic age such superimposition of data led to [[John Snow (physician)|Dr. John Snow]] discovering the cause of cholera. Today, it is used by agencies as diverse as wildlife conservationists and militaries around the world.


Even when GIS is not involved, most cartographers now use a variety of computer graphics programs to generate new maps.  
Even when GIS is not involved, most cartographers now use a variety of computer graphics programs to generate new maps.  


Interactive, computerised maps are commercially available, allowing users to ''zoom in'' or ''zoom out'' (respectively meaning to increase or decrease the scale), sometimes by replacing one map with another of different scale, centred where possible on the same point.  In-car [[Satellite navigation|satellite navigation systems]] are computerised maps with route-planning and advice facilities which monitor the user's position with the help of satellites.
Interactive, computerised maps are commercially available, allowing users to ''zoom in'' or ''zoom out'' (respectively meaning to increase or decrease the scale), sometimes by replacing one map with another of different scale, centred where possible on the same point.  In-car [[satellite navigation]] systems are computerised maps with route-planning and advice facilities which monitor the user's position with the help of satellites.


From the computer scientist's point of view, zooming in entails one or a combination of:
From the computer scientist's point of view, zooming in entails one or a combination of:
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*(2) may apply to text and (3) to the outline of a map feature such as a forest or building.   
*(2) may apply to text and (3) to the outline of a map feature such as a forest or building.   
*(1) may apply to the text (displaying labels for more features), while (2) applies to the rest of the image.  Text is not necessarily enlarged when zooming in. Similarly, a road represented by a double line may or may not become wider when one zooms in.   
*(1) may apply to the text (displaying labels for more features), while (2) applies to the rest of the image.  Text is not necessarily enlarged when zooming in. Similarly, a road represented by a double line may or may not become wider when one zooms in.   
*The map may also have layers which are partly [[raster graphics]] and partly [[vector graphics]].  For a single raster graphics image (2) applies until the pixels in the image file correspond to the pixels of the display, thereafter (3) applies.
*The map may also have layers which are partly [[raster graphics]] and partly vector graphics.  For a single raster graphics image (2) applies until the pixels in the image file correspond to the pixels of the display, thereafter (3) applies.


See also [[Webpage#Graphics|Webpage (Graphics)]], [[Portable Document Format#Layers|PDF (Layers)]], [[Mapquest]], [[Google Maps]], [[Google Earth]] or [[Yahoo! Maps]].
See also [[Webpage#Graphics|Webpage (Graphics)]], [[Portable Document Format#Layers|PDF (Layers)]], [[Mapquest]], [[Google Maps]], Google Earth or [[Yahoo! Maps]].


==References==
== References ==
<references/>
<references/>


Line 82: Line 82:
*Denis E. Cosgrove (ed.) ''Mappings''. Reaktion Books, 1999 ISBN 1-86189-021-4
*Denis E. Cosgrove (ed.) ''Mappings''. Reaktion Books, 1999 ISBN 1-86189-021-4


==See also==
== See also ==
; General
; General
*[[Cartography]]
*Cartography
*[[History of cartography]]
*[[History of cartography]]
*[[Geography]]
*Geography
*[[Atlas]]
*Atlas
*[[Ancient world maps]]
*[[Ancient world maps]]
*[[Globe]]
*Globe


; Map design and types
; Map design and types
Line 96: Line 96:
*[[Pictorial maps]]
*[[Pictorial maps]]
*[[World map]]
*[[World map]]
*[[Topographic map]]
*Topographic map
*[[Geologic map]]
*[[Geologic map]]
*[[Dymaxion map]]
*[[Dymaxion map]]
*[[Road atlas]]
*[[Road atlas]]
*[[Street map]]
*Street map
*[[Nautical chart]]
*Nautical chart
*[[Cartogram]]
*[[Cartogram]]
*[[Plat]]
*[[Plat]]
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== External links ==
== External links ==
{{linkfarm}}
{{linkfarm}}
{{commonscat|maps}}
 


=== Map discussion and history ===
=== Map discussion and history ===
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* [http://www.flourish.org/upsidedownmap/ The Upsidedown Map Page] Pictures and info about maps which are oriented without North at the top
* [http://www.flourish.org/upsidedownmap/ The Upsidedown Map Page] Pictures and info about maps which are oriented without North at the top
* [http://www.citoplan.nl/citoplan/img/legenda_groot.gif Example of map legends (Cito-Plan city maps)]
* [http://www.citoplan.nl/citoplan/img/legenda_groot.gif Example of map legends (Cito-Plan city maps)]
* [http://en.wikipedia.org/wiki/Wikipedia:Maps Wikipedia:Maps], use of maps on [[Wikipedia]]
* [[wp-en:Wikipedia:Maps|Wikipedia:Maps]], use of maps on [[Wikipedia]]
* [http://slashgeo.org slashgeo.org] - Community-driven and ad-free website for news and discussions about Maps and Geospatial technologies
* [http://slashgeo.org slashgeo.org] - Community-driven and ad-free website for news and discussions about Maps and Geospatial technologies
* [http://www.newyorker.com/fact/content/articles/060424fa_fact/ Getting There] Article on Online Maps from The New Yorker
* [http://www.newyorker.com/fact/content/articles/060424fa_fact/ Getting There] Article on Online Maps from The New Yorker
Line 162: Line 162:
National:
National:
* [http://www.nationalatlas.gov/ National Atlas of the United States]
* [http://www.nationalatlas.gov/ National Atlas of the United States]
* [http://nationalmap.usgs.gov/ National Map], [[United States Geological Survey]]
* [http://nationalmap.usgs.gov/ National Map], United States Geological Survey
* [http://www.terraserver-usa.com/ TerraServer-USA] and [http://www.topozone.com/ TopoZone] host USGS topographic maps (and aerial photos on [[TerraServer-USA]]); [http://historical.maptech.com/ Maptech] hosts historical USGS topos in the northeast United States.
* [http://www.terraserver-usa.com/ TerraServer-USA] and [http://www.topozone.com/ TopoZone] host USGS topographic maps (and aerial photos on [[TerraServer-USA]]); [http://historical.maptech.com/ Maptech] hosts historical USGS topos in the northeast United States.
* [http://atlas.gc.ca/site/english/index.html Atlas of Canada]
* [http://atlas.gc.ca/site/english/index.html Atlas of Canada]
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<!--New category to enable a WikiAtlas-->
<!--New category to enable a WikiAtlas-->


{{Link FA|hr}}
 


[[bn:মানচিত্র]]
[[bn:মানচিত্র]]
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[[gl:Mapa]]
[[gl:Mapa]]
[[ko:지도]]
[[ko:지도]]
[[hr:Karta]]
hr:Karta
[[id:Peta]]
id:Peta
[[he:מפה]]
[[he:מפה]]
[[lb:Landkaart]]
lb:Landkaart
[[hu:Térkép]]
[[ml:ഭൂപടം]]
[[ml:ഭൂപടം]]
[[no:Kart]]
no:Kart
[[nn:Kart]]
[[nn:Kart]]
[[pl:Mapa]]
[[pl:Mapa]]
[[pt:Mapa]]
[[ru:Географическая карта]]
[[ru:Географическая карта]]
[[sco:Cairt]]
[[sco:Cairt]]
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[[sk:Mapa]]
[[sk:Mapa]]
[[sl:Zemljevid]]
[[sl:Zemljevid]]
[[su:Atlas]]
su:Atlas
[[th:แผนที่]]
[[th:แผนที่]]
[[vi:Bản đồ]]
[[vi:Bản đồ]]
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[[zh:地图]]
[[zh:地图]]
[[zh-classical:地圖]]
[[zh-classical:地圖]]
[[Category:Hiking equipment]]
[[Category:Hiking equipment]]


[[ar:خريطة]]
[[ar:خريطة]]
[[da:Kort]]
[[de:Karte]]
[[de:Karte]]
[[eo:Mapo]]
[[fi:Kartta]]
[[fi:Kartta]]
[[fr:Carte]]
[[fr:Carte]]
[[nl:Stafkaart]]
[[it:Carta topografica]]
[[nl:Topografische kaart]]
[[sv:Karta]]
[[sv:Karta]]

Latest revision as of 08:24, 19 August 2021

This article was imported from Wikipedia and needs to be ScoutWikified. You can help ScoutWiki by fixing it.
For other uses, see Map (disambiguation). For the acronyms, see MAP and MAPS

A map is a simplified depiction of a space which highlights relations between components (objects, regions) of that space. Most usually a map is a two-dimensional, geometrically accurate representation of a three-dimensional space; e.g., a geographical map. More generally, maps can be devised to represent any local property of the world or part of it, or any other space, such as the brain (see Brain mapping).

Geographical maps

File:Starmap1600.jpg
A celestial map from the 17th century, by the Dutch cartographer Frederik de Wit.

The science and art of map-making is cartography; see that page for further discussion of the history of maps and map-making.

Map-making dates back to the Stone Age and appears to predate written language by several millennia. One of the oldest surviving maps is painted on a wall of the Catal Huyuk settlement in south-central Anatolia (now Turkey); it dates from about 6200 BC. [1] One who makes maps professionally or privately is called a cartographer.

While we tend to think of maps today as products of a rationalistic, scientific world-view, maps also have a mythic quality. Pre-modern maps, and mapping traditions outside the Western tradition, often merge geography with non-scientific cosmography, showing the relationship of the viewer to the universe. Medieval "T-O" maps, for example, show Jerusalem at the centre of the world, and in some cases related the "body" of the Earth to the body of Christ. By contrast, navigational (or "Portolan") charts of the Mediterranean from the same period are remarkably accurate. Even today, maps can be powerful rhetorical tools beyond their purely practical value, and this has been the source of much fruitful map criticism over the last twenty years, notably in the works of J.B. Harley, Mark Monmonier, and Denis Wood.

Physical map of the Earth.

Geographic maps are abstract representations of the world. It is, of course, this abstraction that makes them useful. Lewis Carroll made this point humorously in Sylvie and Bruno with his mention of a fictional map that had "the scale of a mile to the mile". A character notes some practical difficulties with this map and states that "we now use the country itself, as its own map, and I assure you it does nearly as well". This concept is elaborated in a one-paragraph story by Jorge Luis Borges, generally known in English as "On Exactitude in Science".

Road maps are perhaps the most widely used maps today, and form a subset of navigational maps, which also include aeronautical and nautical charts, railroad network maps, and hiking and bicycling maps. In terms of quantity, the largest number of drawn map sheets is probably made up by local surveys, carried out by municipalities, utilities, tax assessors, emergency services providers, and other local agencies. Many national surveying projects have been carried out by the military, such as the British Ordnance Survey (now a civilian government agency internationally renowned for its comprehensively detailed work).

Orientation of maps

The Hereford Mappa Mundi, about 1300, Hereford Cathedral, England. A classic "T-O" map with Jerusalem at centre, east toward the top, Europe the bottom left and Africa on the right.

The most common cartographic convention is that North is at the top of a map. This is far from universal, however:

  • Polar maps of the Arctic or Antarctic regions are conventionally centered on the pole, making "north is up" meaningless.
  • Azimuthal or Gnomonic projections are often used in planning air routes, centered on specific origin points.
  • Richard Edes Harrison produced a striking series of maps during and after World War II for Fortune magazine. These used "bird's eye" projections to emphasize globally strategic "fronts" in the air age, pointing out proximities and barriers not as apparent on a conventional rectangular projection of the world.
  • Buckminster Fuller's Dymaxion maps are based on a projection of the Earth's sphere onto an icosahedron. The resulting triangular pieces may be arranged in any order or orientation.
  • Maps from non-Western traditions are oriented a variety of ways. Old maps of Edo show the Japanese imperial palace as the "top," but also at the centre, of the map. Labels on the map are oriented in such a way that you cannot read them properly unless you put the imperial palace above your head.
  • Medieval European T and O maps such as the Hereford Mappa Mundi were centred on Jerusalem with east at the top. Indeed, prior to the reintroduction of Ptolemy's Geography to Europe around 1400, there was no single convention in the West. Portolan charts, for example, are oriented to the shores they describe.
  • Route and channel maps have traditionally been oriented to the road or waterway they describe.

Scale and accuracy

Many but not all maps are drawn to a scale, allowing the reader to infer the actual sizes of, and distances between, depicted objects. A larger scale shows more detail, thus requiring a larger map to show the same area. For example, maps designed for the hiker are often scaled at the ratio 1:24,000, meaning that 1 of any unit of measurement on the map corresponds to 24,000 of that same unit in reality; while maps designed for the motorist are often scaled at 1:250,000. Maps which use some quality other than physical area to determine relative size are called cartograms.

A famous example of a map without scale is the London Underground map, which best fulfils its purpose by being less physically accurate and more visually communicative to the hurried glance of the commuter. This is not a cartogram (since there is no consistent measure of distance) but a topological map that also depicts approximate bearings. The simple maps shown on some directional road signs are further examples of this kind.

In fact, most commercial navigational maps, such as road maps and town plans, sacrifice an amount of accuracy in scale to deliver a greater visual usefulness to its user, for example by exaggerating the width of roads. With the end-user similarly in mind, cartographers will censor the content of the space depicted by a map in order to provide a useful tool for that user. For example, a road map may or may not show railroads, and if it does, it may show them less clearly than highways.

Some maps such as topographical maps show constant values such as average temperature, these are often represented, along with other characteristics, depending on the scale of the map, in the form of Isolines. Isolines are often on a map or chart along which there is constant value (temperature, pressure, or rainfall).

World maps and projections

Main article: World map
Map of large underwater features. (1995, NOAA)

Maps of the world or large areas are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical is to show features of geography such as mountains, soil type or land use. Geological maps show not only the physical surface, but characteristics of the underlying rock, fault lines, and subsurface structures.

Maps that depict the surface of the Earth also use a projection, a way of translating the three-dimensional real surface of the geoid to a two-dimensional picture. Perhaps the best-known world-map projection is the Mercator Projection, originally designed as a form of nautical chart.

Airplane pilots use aeronautical charts based on a Lambert conformal conic projection, in which a cone is laid over the section of the earth to be mapped. The cone intersects the sphere (the earth) at one or two parallels which are chosen as standard lines. This allows the pilots to plot a great-circle route approximation on a flat, two-dimensional chart.

Electronic maps

A USGS digital raster graphic.

From the last quarter of the 20th century, the indispensable tool of the cartographer has been the computer. Much of cartography, especially at the data-gathering survey level, has been subsumed by Geographic Information Systems (GIS). The functionality of maps has been greatly advanced by technology allowing, for example, the superimposition of spatially located variables onto existing geographical maps. Having local information such as rainfall level, distribution of wildlife, or demographic data integrated within the map makes for more efficient analysis and better decision making. In the pre-electronic age such superimposition of data led to Dr. John Snow discovering the cause of cholera. Today, it is used by agencies as diverse as wildlife conservationists and militaries around the world.

Even when GIS is not involved, most cartographers now use a variety of computer graphics programs to generate new maps.

Interactive, computerised maps are commercially available, allowing users to zoom in or zoom out (respectively meaning to increase or decrease the scale), sometimes by replacing one map with another of different scale, centred where possible on the same point. In-car satellite navigation systems are computerised maps with route-planning and advice facilities which monitor the user's position with the help of satellites.

From the computer scientist's point of view, zooming in entails one or a combination of:

  1. replacing the map by a more detailed one
  2. enlarging the same map without enlarging the pixels, hence showing more detail by removing less information compared to the less detailed version
  3. enlarging the same map with the pixels enlarged (replaced by rectangles of pixels); no additional detail is shown, but, depending on the quality of one's vision, possibly more detail can be seen; if a computer display does not show adjacent pixels really separate, but overlapping instead (this does not apply for an LCD, but may apply for a cathode ray tube), then replacing a pixel by a rectangle of pixels does show more detail. A variation of this method is interpolation.

For example:

  • Typically (2) applies to a Portable Document Format (PDF) file. The increase in detail is, of course, limited to the information contained in the file: enlargement of a curve may eventually result in a series of standard geometric figures such as straight lines or arcs of circles.
  • (2) may apply to text and (3) to the outline of a map feature such as a forest or building.
  • (1) may apply to the text (displaying labels for more features), while (2) applies to the rest of the image. Text is not necessarily enlarged when zooming in. Similarly, a road represented by a double line may or may not become wider when one zooms in.
  • The map may also have layers which are partly raster graphics and partly vector graphics. For a single raster graphics image (2) applies until the pixels in the image file correspond to the pixels of the display, thereafter (3) applies.

See also Webpage (Graphics), PDF (Layers), Mapquest, Google Maps, Google Earth or Yahoo! Maps.

References

  1. ↑ *Miles Harvey, The Island of Lost Maps: A True Story of Cartographic Crime. New York : Random House, 2000 ISBN 0-7679-0826-0, cited above; also ISBN 0-375-50151-7
  • David Buisseret, ed., Monarchs, Ministers and Maps: The Emergence of Cartography as a Tool of Government in Early Modern Europe. Chicago: University of Chicago Press, 1992, ISBN 0-226-07987-2
  • Mark Monmonier, How to Lie with Maps, ISBN 0-226-53421-9
  • What technology like GIS and electronic maps have done for mapping
  • O'Connor, J.J. and E.F. Robertson, The History of Cartography. Scotland : St. Andrews University, 2002.
  • Denis E. Cosgrove (ed.) Mappings. Reaktion Books, 1999 ISBN 1-86189-021-4

See also

General
Map design and types
Modern maps
Map history
Related Topics

External links

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Map discussion and history

Map link sites

Modern maps and atlases online

World:

National:

Antique and historical maps online

Online map creation tools

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