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

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). 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 by satellite the position of the user.

From the computer scientist's standpoint, 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 show more detail
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 that interpolation is performed.

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.

The word "map" has also been used to describe places within video games, such as SOCOM II: U.S. Navy SEALs and Counter-Strike, that players choose to compete on, as a synonym for level.

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

References

• 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 0226079872]
• Miles Harvey, The Island of Lost Maps: A True Story of Cartographic Crime. New York : Random House, 2000. [ISBN 0767908260, cited above; also ISBN 0375501517]
• Mark Monmonier, How to Lie with Maps, [ISBN 0226534219]
• O'Connor, J.J. and E.F. Robertson, The History of Cartography. Scotland : St. Andrews University, 2002. http://www-gap.dcs.st-and.ac.uk/~history/HistTopics/Cartography.html

See also

• Geography
• Atlas (cartography)
• World map
• Topographic map
• Geologic map
• Dymaxion map
• Roadmap
• Navigation map
• Cartogram
• Plat
• Floorplan
• Bradshaws, including maps of the British railway network, first published in 1839
• Template_talk:Mapquest - Linking Mapquest maps to articles.
• Sanborn Maps - detailed American fire insurance maps
• Map design
• Ordnance Survey
• Google Maps
• Japanese map symbols
• Planform
• Plan view

External links

• Microsoft: MSN [1]
  • world atlas (the whole world on the same scale: 4 km = 49 pixels, 82 m / pixel)
  • North America (Canada, US, Mexico), US to street level, Mexico only some parts to street level (for the other parts street level scale is available, but it shows blank maps with e.g. only one dot to represent a village)
  • Western Europe to street level, see map of area covered
  • Australia
  • Brazil
• US Map: ABMap - Interactive World Map and detailed united states street map
• Antique Maps Yellow News and Commentary about Antique Maps (Blog)
• Historical Maps from the Hargrett Library Collection (University of Georgia) --browse over 1000 maps from as early as 1544-- DjVu format; requires free plugin or JAVA
• Historical Maps from the Portal to Texas History
• atlases with maps by country:
  • PopulationData.net
  • [2] The World Factbook
    • the same maps but with a faster, cleaner directory: [3]
  • Holt, Rinehart and Winston
  • Infoplease
• UT scanned collection - University of Texas at Austin (also at [4] and [5]; thumbnails at Google)
  • list of links including those to external sites
• Online Map Creation: Webinterface to GMT mapping package
  • new version: Planiglobe
• MapZones Map of all countries
• Multimap world atlas: on UK, US, Canada, Australia and Western Europe more detailed than the rest of the world; the list of scales to select from is location-dependent - also provides geographic coordinates of a location selected from a map.
• MapQuest [6]: on US, Canada and Western Europe more detailed than the rest of the world - the list of scales to select from is not location-dependent: for part of the world several zoom level links lead to an image with just the message "No Data Available".
• Atlas of the World A world atlas with hundreds of very detailed and elaborate maps from every part of the world
• Yahoo Maps: on US, Canada, Germany, France, Spain, Italy
• Yahoo Germany: on France, UK, Germany, Italy, Spain, Portugal, Austria, Switzerland, Benelux
• Maps of the World (ger.)
• krak.dk: Interactive map of Denmark
• Routenplaner24 Street Maps and Route Planner in Germany
• Map South Pacific: on Polynesia, Melanesia, Micronesia
• World and Continent Maps
• Street Maps in Switzerland, Austria and Germany
• MapMachine (National Geographic/ESRI)
• National Atlas of the United States
  • US state maps
• Example of legend (Cito-Plan city maps)
• http://www.geocities.com/marcoschmidt.geo/geo-data.html
• USGS National Map
• Free Maps and Route Planner on Europe
• Maps of OutdoorMountain
• Online Map Catalogs in North America and Europe Lists some good places to search for online maps
• The fascinating world of maps and mapping Lists all kinds of maps
• Map collections Intorductory page to help navigate the online map resources
• A listing of over 5000 websites describing holdings of manuscripts, archives, rare books, historical photographs, and other primary sources for the research scholar
• Brazilian and World Maps Vector PDF maps of Brazilian states
• Hong Kong Maps CentaMap
• FreeRoute Germany
• Links to on-line atlases
• Link Directory for Maps Link directory of map libraries and societies, antique maps and world, regional, travel, historical and other map resources.
• Royalty Free Maps Royalty Free Vector and Bitmap Maps, available in Illustrator format.
• Map Room - a weblog about maps
• Antique and Rare Maps - Art Source International - Links to rare and antique maps and to cartography resources.
• Google
  • Google Earth: Interactive map of the world
  • Google Maps Google's map system, similar to Mapquest.
• The Upsidedown Map Page Pictures and info about maps which are oriented without North at the top
• Wikipedia:Maps, use of maps on Wikipedia

Note that map services with various zoom levels sometimes show a new map item, such as a new bridge, only on a smaller-scale map and not on an available larger scale map, because the latter is not as often updated, see e.g. the Tuas Second Link on [7], and larger scales which do not show it.bg:Карта bn:মানচিত্র ca:Plànol cs:Mapa da:Kort (geografi) de:Karte (Kartografie) et:Kaart es:Mapa eo:Mapo fr:Carte gl:Mapa hr:Karta id:Peta he:מפה hu:Térkép nl:Kaart (cartografie) ja:地図 pl:Mapa pt:Mapa sl:Zemljevid su:Atlas fi:Kartta sv:Karta vi:Bản đồ tr:Harita zh:地图