Jump to content

Wikipedia:WikiProject Geographical coordinates

From Wikipedia, the free encyclopedia
(Redirected from Wikipedia:Coord)

WikiProject Geographical coordinates aims to better organize location information in articles containing a set of numbers that identifies location on and relative to the Earth. In particular, we aim to establish a standard for uniform handling of latitude and longitude coordinates as given in various Wikipedia articles, somewhat analogous to how ISBN numbers are handled.

Quick Geographical coordinates how to

NOTE: This is a concept currently under development, so this is subject to change.

To add 57°18′22″N 4°27′32″W / 57.30611°N 4.45889°W / 57.30611; -4.45889 to the top of an article, use {{Coord}}, thus:

{{Coord|57|18|22|N|4|27|32|W|display=title}}

These coordinates are in degrees, minutes, and seconds of arc.

"title" means that the coordinates will be displayed next to the article's title at the top of the page (in desktop view only; title coordinates do not display in mobile view) and before any other text or images. It also records the coordinates as the primary location of the page's subject in Wikipedia's geosearch API.

To add 44°06′45″N 87°54′47″W / 44.1124°N 87.9130°W / 44.1124; -87.9130 to the top of an article, use either

{{Coord|44.1124|N|87.9130|W|display=title}}

(which does not require minutes or seconds but does require the user to specify north/ south and east/west) or

{{Coord|44.1124|-87.9130|display=title}}

(in which the north and east are presumed by positive values while the south and west are negative ones). These coordinates are in decimal degrees.

  • Degrees, minutes and seconds, when used, must each be separated by a pipe ("|").
  • Map datum must be WGS84 if possible (except for off-Earth bodies).
  • Avoid excessive precision (0.0001° is <11 m, 1″ is <31 m).
  • Maintain consistency of decimal places or minutes/seconds between latitude and longitude.
  • Latitude (N/S) must appear before longitude (E/W).

Optional coordinate parameters follow the longitude and are separated by an underscore ("_"):

Other optional parameters are separated by a pipe ("|"):

  • display
    |display=inline (the default) to display in the body of the article only,
    |display=title to display at the top of the article only (in desktop view only; title coordinates do not display in mobile view), or
    |display=inline,title to display in both places.
  • name
    name=X to label the place on maps (default is PAGENAME)

Thus: {{Coord|44.1172|-87.9135|dim:30_region:US-WI_type:event

|display=inline,title|name=accident site}}

Use |display=title (or |display=inline,title) once per article, for the subject of the article, where appropriate.

WorldWind displaying WP coordinates (see applications below)
[edit]

WikiProject Council includes this WikiProject in its Geographical directory. This WikiProject is an offshoot of WikiProject Maps:

WikiProject Geography
WikiProject Maps
WikiProject Geographical coordinates

...and is the parent project of:

Wikipedia-World

Other WikiProjects that make use of geographical coordinates include:

Associated Portals

[edit]

The AtlasPortal is associated with WikiProject Geography.

The Geography Portal is associated with WikiProject Geography.

Participants

[edit]

This list has been moved to its own page.

Goals

[edit]
  1. Should provide a uniform markup for all geographic coordinates
  2. Should provide a user-preferred appearance for all geographic coordinates
  3. Markup should be easy and natural to use
  4. ☑.svg Should be able to have a uniform, extensible way of accessing all types of map resources, avoiding having direct external links to maps in articles
  5. ☑.svg Clicking on a reference navigates directly to a page with external pointers to various resources, with coordinates automatically embedded where possible. The resources can be maps of various kinds, topological charts, satellite photos and others.
  6. ☑.svg Create a database of points, enabling generation of navigatable maps with a clickable icon appearing for every location for which there is a Wikipedia article. This has been implemented for NASA World Wind, Google Earth (see below) and Google maps (see below).
  7. ☑.svg Serve as a tool for finding Wikipedia articles describing nearby locations. See also meta:Wikipediatlas.
  8. Adhere to existing Internet standards for geographic coordinates as far as possible[clarification needed] such as using WGS84 for terrestrial coordinates

Usage guidelines

[edit]
See also MOS:COORDS

In general, coordinates should be added to any article about a location, structure, or geographic feature that is more or less fixed in one place. Such items can vary in size from a single tree (or smaller) to entire oceans or continents. Coordinates should also be added to articles about events that are associated with a single location, for example, the Ufa train disaster. Guidelines for less obvious situations are given below.

Coordinates are appropriate for the top articles or within infoboxes of the following types of articles:

  • Businesses/organizations with a single location (even if they are defunct)
  • Demolished buildings/structures
  • Buildings/structures that have been proposed, but not yet built (if there is a reliable source for the location)
  • Permanently docked ships (and shipwrecks)

Do not add coordinates to the following types of articles:

  • Biographies of living people
  • Works of art (other than permanent outdoor statues, installations or murals)
  • Sports teams (add to the stadium article instead)
  • Businesses with multiple locations (although listing coords for individual locations in a table may be appropriate)
  • Ships that are not permanently docked or sunk

Other types of articles may be decided on a case-by-case basis.

Which coordinates to use

[edit]

National mapping agencies such as the Geographic Names Information System (GNIS), Ordnance Survey (OS), and Geographical Names Board of Canada (GNBC) are usually reliable sources for coordinates. The GEOnet Names Server (GNS) database is not reliable. Always double check the coordinates on an internet mapping service. For other locations, the following points should be considered:

  • For villages, towns, communities, etc., use the current centre. Where this is difficult, choose the earliest known settlement of that name. Be aware that the GNIS coordinates may be an arbitrarily chosen civic feature, as that was the usual rule.
  • For military and industrial establishments (e.g., castles, barracks, dockyards, car plants) use the main gate.
  • For administrative districts, use the head office.
  • For geographical features with an area, such as lakes, reservoirs, and islands, use a point reasonably in the center of the feature. (Remember not to specify too much precision; see Precision guidelines below.)
  • For linear features, see Wikipedia:WikiProject Geographical coordinates/Linear. Be aware that the GNIS primary coordinates will usually be of the feature "mouth" and thus may differ.

Markup

[edit]

The practical usage of coordinate markup in Wikipedia is described in the style guide for geographical coordinates. For use on maps and other services, parameters may also be required.

A complete entry could for example be: {{coord|51|28|40|N|0|0|6|W|type:landmark_scale:2000_region:GB|display=title}}

See also: Obtaining coordinates

[edit]

The template {{WikiProject Geographical coordinates}} may be added to relevant Talk pages. This adds the page to several categories and displays as:

WikiProject iconGeographical coordinates
WikiProject iconWikiProject Geographical coordinates is of interest to WikiProject Geographical coordinates, which encourages the use of geographical coordinates in Wikipedia. If you would like to participate, please visit the project page, where you can join the project and see a list of open tasks.

Implementation details

[edit]

Coordinate templates

[edit]

There are two ways of specifying coordinates:

  1. {{coord}} – Accepts multiple data formats and supports a style sheet preference for display format, plus a Geo microformat. Coord may be placed anywhere in the article source text, inline, with prose text. For example "Mount Everest is at {{coord|27|59|16|N|86|56|40|E}}", which displays as "Mount Everest is at 27°59′16″N 86°56′40″E / 27.98778°N 86.94444°E / 27.98778; 86.94444". To display coordinates at the page's top, near the article's title, in a skin-dependent way, use display=title (see example at Krasnoyarsk hydroelectric dam). To display both inline and top, use display=inline,title.
  2. Infoboxes – Many infobox templates for places have a parameter, typically |coordinates=, for specifying a place's coordinates. The template internally uses {{coord}} and may therefore also display in the title area. See Template:Infobox Settlement and Template:Infobox Mountain for documentation, or, usage examples at Los Angeles and Mount Everest.

(Before September 2008, there was a widely-used family of templates of the form coor .... These are deprecated and have been replaced by {{coord}}. For an overview of choices: WikiProject Geographical coordinates/comparison.)

Parameters

[edit]

Following the geographical coordinate, further parameters can optionally be supplied, separated by underscores. This helps display suitable map resources (see Template:GeoTemplate), and will help Wikimaps become fully functional.

For example:

{{coord|61.1631|-149.9721|type:landmark_globe:earth_region:US-AK_scale:150000_source:gnis|name=Kulis Air National Guard Base}} displays 61°09′47″N 149°58′20″W / 61.1631°N 149.9721°W / 61.1631; -149.9721 (Kulis Air National Guard Base)

It has

  • type:landmark
  • globe:earth
  • region:US-AK
  • scale:150000
  • source:gnis
type:T
[edit]

The type: parameter specifies the type of location for reverse mapping (for instance, to select a marker icon in the WikiMiniAtlas).

It also sets the map scale, which can however be overridden by dim: or scale:.

Valid types are:

T Description Map scale
adm1st Administrative unit of country, 1st level (province, state), see table, e.g. U.S. states 1:1,000,000
adm2nd Administrative unit of country, 2nd level, see table, e.g. county (United States) 1:300,000
adm3rd Administrative unit of country, 3rd level, see table 1:100,000
airport airports and airbases 1:30,000
city(pop) cities, towns, villages, hamlets, suburbs, subdivisions, neighborhoods, and other human settlements (including unincorporated and/or abandoned ones) with known population
Please replace pop with a number. Commas in pop will be ignored. There should be no blanks.
1:30,000 ... 1:300,000
city cities, towns, villages, hamlets, suburbs, subdivisions, neighborhoods, and other human settlements (including unincorporated and/or abandoned ones) with unspecified population
These are treated as minor cities.
1:100,000
country (e.g. "type:country") 1:10,000,000
edu schools, colleges, and universities 1:10,000
event one-time or regular events and incidents that occurred at a specific location, including battles, earthquakes, festivals, and shipwrecks 1:50,000
forest forests and woodlands 1:50,000
glacier glaciers and icecaps 1:50,000
isle islands and isles 1:100,000
landmark buildings (including churches, factories, museums, theatres, and power plants but excluding schools and railway stations), caves, cemeteries, cultural landmarks, geologic faults, headlands, intersections, mines, ranches, roads, structures (including antennas, bridges, castles, dams, lighthouses, monuments, and stadiums), tourist attractions, valleys, and other points of interest 1:10,000
mountain peaks, mountain ranges, hills, submerged reefs, and seamounts 1:100,000
pass mountain passes 1:10,000
railwaystation stations, stops, and maintenance areas of railways and trains, including railroad, metro, rapid transit, underground, subway, elevated railway, etc. 1:10,000
river rivers, canals, creeks, brooks, and streams, including intermittent ones 1:100,000
satellite geo-stationary satellites 1:10,000,000
waterbody bays, fjords, lakes, reservoirs, ponds, lochs, loughs, meres, lagoons, estuaries, inland seas, and waterfalls 1:100,000
camera To indicate the location of where a specific image was taken. This type is used by coordinate templates on File pages. 1:10,000
Default scale: if no type is used or the type is not defined in the GeoHack extension 1:300,000
Samples
T Markup Result
waterbody {{coord|46|43|N|7|58|E|type:waterbody}} 46°43′N 7°58′E / 46.717°N 7.967°E / 46.717; 7.967
dim:D
[edit]

The dim: parameter defines the diameter of a viewing circle centered on the coordinates. While the default unit of measurement is metres, the km suffix may be appended to indicate kilometres. The dim: parameter overrides the scale implied by any type: parameter.

Syntax — dim:<width><units>

width — integer number of metres (m) or kilometres (km)
units — m or km, if not specified, defaults to m

GeoHack uses dim: to select a map scale such that the viewing circle appears roughly 10 centimetres (4 in) in diameter on a 72 dpi computer monitor. If no dim:, type:, or scale: parameters are provided, GeoHack uses its default viewing circle of 30 kilometres (19 mi).

Samples
Subject Dim Markup Result
Buckingham Palace 120m {{coord|51.501|-0.142|dim:120m}} 51°30′04″N 0°08′31″W / 51.501°N 0.142°W / 51.501; -0.142
London 10km {{coord|51.507222|-0.1275|dim:10km}} 51°30′26″N 0°07′39″W / 51.507222°N 0.1275°W / 51.507222; -0.1275
Western Hemisphere 10,000 kilometres (6,200 mi) {{coord|0|N|90|W|dim:10000km}} 0°N 90°W / 0°N 90°W / 0; -90
Ohio 400 kilometres (250 mi) {{coord|40.5|-82.5|dim:400km}} 40°30′N 82°30′W / 40.5°N 82.5°W / 40.5; -82.5
Dresden 20,000 metres (12 mi) {{coord|51.03|13.73|dim:20000}} 51°02′N 13°44′E / 51.03°N 13.73°E / 51.03; 13.73
Statue of Liberty 100 metres (330 ft) {{coord|40.6892|-74.0445|dim:100}} 40°41′21″N 74°02′40″W / 40.6892°N 74.0445°W / 40.6892; -74.0445
scale:N
[edit]

The scale: parameter specifies the desired map scale as 1:N, overriding the scale implied by any type: parameter.

GeoHack uses scale: to select a map scale for a 72 dpi computer monitor. If no dim:, type:, or scale: parameters are provided, GeoHack uses its default scale of 1:300,000.

Samples
Subject Scale Markup Result
Big Ben 1:500 {{coord|51.500611|N|0.124611|W|scale:500}} 51°30′02″N 0°07′29″W / 51.500611°N 0.124611°W / 51.500611; -0.124611
Palace of Westminster 1:5,000 {{coord|51.5006|N|0.1246|W|scale:5000}} 51°30′02″N 0°07′29″W / 51.5006°N 0.1246°W / 51.5006; -0.1246
City of Westminster 1:50,000 {{coord|51.501|N|0.125|W|scale:50000}} 51°30′04″N 0°07′30″W / 51.501°N 0.125°W / 51.501; -0.125
Greater London 1:500,000 {{coord|51.50|N|0.12|W|scale:500000}} 51°30′N 0°07′W / 51.50°N 0.12°W / 51.50; -0.12
region:R
[edit]

The region: parameter specifies the political region for terrestrial coordinates. It is used to select appropriate map resources. If no region: parameter is provided, GeoHack attempts to determine the region from the coordinates.

The region should be supplied as either a two character ISO 3166-1 alpha-2 country code or an ISO 3166-2 region code.

Examples of ISO 3166-1 alpha-2 codes:

  • AQ Antarctica
  • AU Australia
  • BR Brazil
  • DE Germany
  • GB United Kingdom
  • HK Hong Kong
  • IN India
  • LK Sri Lanka
  • RU Russia
  • US United States

Examples of ISO 3166-2 region codes:

  • DE-TH Thuringia, Germany
  • GB-BIR Birmingham, England
  • NO-03 Oslo, Norway
  • US-NY New York state, US

The oceans have the following Wiki assigned code elements per de:Vorlage:Coordinate#Ozeane.

  • XN Arctic Ocean
  • XA Atlantic Ocean
  • XI Indian Ocean
  • XP Pacific Ocean
  • XS Southern Ocean

In addition, two Wiki assigned code elements can be used with {{coord}}:

  • XZ for objects in or above international waters (similar to UN/LOCODE).
  • ZZ for use in examples.
Samples
Focus region Region Markup Result
Switzerland CH {{coord|46.9524|N|7.4396|E|region:CH}} 46°57′09″N 7°26′23″E / 46.9524°N 7.4396°E / 46.9524; 7.4396
Berlin, Germany DE-BE {{coord|52.5164|N|13.3775|E|region:DE-BE}} 52°30′59″N 13°22′39″E / 52.5164°N 13.3775°E / 52.5164; 13.3775
globe:G
[edit]

The globe: parameter specifies the planet, dwarf planet, asteroid, or natural satellite upon which the coordinates reside. Apart from earth (the default), recognized values are: mercury, venus, moon, mars, phobos, deimos, ceres, vesta, jupiter, ganymede, callisto, io, europa, mimas, enceladus, tethys, dione, rhea, titan, hyperion, iapetus, phoebe, miranda, ariel, umbriel, titania, oberon, triton, pluto, and charon.

Samples
Subject G Markup Result
Kittu Crater ganymede {{coord|0.4|N|334.6|W|globe:ganymede}} 0°24′N 334°36′W / 0.4°N 334.6°W / 0.4; -334.6
Viking 2 lander mars {{coord|48.269|N|225.990|W|globe:mars}} 48°16′08″N 225°59′24″W / 48.269°N 225.990°W / 48.269; -225.990
Mozart Crater mercury {{coord|7.8|N|190.5|W|globe:mercury}} 7°48′N 190°30′W / 7.8°N 190.5°W / 7.8; -190.5
Apollo 11 lander moon {{coord|0|40|26.69|N|23|28|22.69|E|globe:moon}} 0°40′26.69″N 23°28′22.69″E / 0.6740806°N 23.4729694°E / 0.6740806; 23.4729694
Ksa Crater titan {{coord|14.0|N|65.4|W|globe:titan}} 14°00′N 65°24′W / 14.0°N 65.4°W / 14.0; -65.4
Venera 13 lander venus {{coord|7.5|S|303|E|globe:venus}} 7°30′S 303°00′E / 7.5°S 303°E / -7.5; 303
Stickney Crater phobos {{coord|1|N|49|W|globe:phobos}} 1°N 49°W / 1°N 49°W / 1; -49

Very rough mapping is provided on geohack for almost all supported globes. The pop-out WikiMiniAtlas system provides limited mapping for Moon, Mars, Mercury, Venus, Io, and Titan, as of February 2021.

The maps roughly implies a coordinate reference system, but does not clearly specify one (unlike Earth's WGS84). Since the template defaults to east longitude, the |W| direction must be specified for globes that measure longitude westward. For celestial coordinates, use {{Sky}} instead.

source:S
[edit]

Specifies, where present, the data source and data source format/datum, and optionally, the original data, presented in parentheses. This is initially primarily intended for use by geotagging robots, so that data is not blindly repeatedly copied from format to format and Wikipedia to Wikipedia, with progressive loss of precision and attributability.

Examples:

  • A lat/long geotag derived from an Ordnance Survey National Grid Reference NM 435 355 found in the English-language Wikipedia would be tagged as "source:enwiki-osgb36(NM435355)"
  • A latitude-longitude location sourced from data taken from the German-language Wikipedia would be tagged as "source:dewiki" – and so on, for other language codes;
  • A location sourced from the public domain GeoNet Names Server database would be tagged as "source:GNS". No datum or format information is needed, since by default all Wikipedia coordinates are in latitude/longitude format based on the WGS84 datum. Similarly, US locations sourced from the similar public domain GNIS database would be tagged as "source:GNIS".

Name

[edit]

{{coord}} takes |name=name

If an article contains several display=inline coordinates, each of these may be supplied with a unique name. This name will be used to display the coordinate on the WikiMiniAtlas, and will cause the template to emit an hCard microformat using that name, even if used within an existing hCard. Do not use when the name is that of a person (e.g for a gravesite), as the generated hCard would be invalid. Also, do not use square brackets in names.

Display preferences

[edit]

To always display coordinates as DMS values, add this to your common.css:

.geo-default { display: inline }
.geo-nondefault { display: inline }
.geo-dec { display: none }
.geo-dms { display: inline }

To always display coordinates as decimal values, add this to your common.css:

.geo-default { display: inline }
.geo-nondefault { display: inline }
.geo-dec { display: inline }
.geo-dms { display: none }

To display coordinates in both formats, add this to your common.css:

.geo-default { display: inline }
.geo-nondefault { display: inline }
.geo-dec { display: inline }
.geo-dms { display: inline }
.geo-multi-punct { display: inline }

If CSS is disabled, or you have an old copy of MediaWiki:Common.css cached, you will see both formats. (You can either clear your cache or manually refresh this URL: [1].)

To disable display of the blue globe adjacent to coordinates, add this to your common.js:

var wma_settings = {enabled:false}

Note that this will disable WikiMiniAtlas.

See also: Wikipedia:Manual of Style/Dates and numbers § Geographical coordinates.

Format

[edit]
  • format=dec will reformat the coordinates to decimal degrees for all readers.
  • format=dms will reformat the coordinates to degrees | minutes | seconds (dms) format for all readers.

Creating new templates

[edit]

When creating new templates or infoboxes, use {{coord}}. Unless a template uses the coordinate data in another way, the {{coord}} template should be the field value. For example, {{infobox lake}} accepts coords = {{coord|45|N|6|E|type:waterbody}}.

If coordinate data are used directly by a template, use the following parameter names for coordinates:

  • lat_d
  • lat_m
  • lat_s
  • lat_NS
  • long_d
  • long_m
  • long_s
  • long_EW

A provision for accepting decimal coordinates is recommended. For example, allow lat_d = 45.678 | long_d = -123.456 and omission of the remaining parameters.

Where the United Kingdom's Ordnance Survey grid references are used as the coordinates, use {{oscoor}}.

For articles which have no coordinates, but need them, use {{coord missing}}.

Linear features

[edit]

For draft guidance on, and examples of, coordinates for linear features (rivers, roads, bridges, tunnels, etc.), see Wikipedia:WikiProject Geographical coordinates/Linear.

How to obtain geographical coordinates

[edit]

See Obtaining geographic coordinates

See also: Category:Articles needing coordinates, Maybe-Checker

Geodetic system

[edit]

All coordinates specified through {{coord}} must be referenced to WGS84, or an equivalent datum. WGS84 is required for some of the conversions done by the geohack extension.

British national grid references of the Ordnance Survey use its own OSGB36 datum, which is correct for use in national grid references; the correct transformations will automatically be applied when national grid coordinates are used in {{oscoor}} tags. However, OSGB36 latitude/longitude coordinates should not be used anywhere in Wikipedia; please use WGS84 lat/long instead.

Precision guidelines

[edit]

Regardless of how coordinates are obtained, consider the precision specified in a Wikipedia article. Reliable secondary sources exist for some locations. Without a reliable source, the larger the object being mapped, the less precise the coordinates need to be. Cities must be specified with a precision of degrees, minutes and seconds to respect historical norms. When the #Which coordinates to use guideline is used, degrees, minutes and seconds or d.dddd are the default. To specify a particular point in the city, such as a building, generally requires precision down to degrees-minutes-seconds or d.dddd° if decimal degrees are used. In the case of objects such as fountains or statues, it may be necessary to use d°m's.s" or d.ddddd°. Higher precisions should be avoided, as they greatly exceed the accuracy of civilian GPS and online mapping services. (Using 4 m accuracy as an estimate for civilian GPS: Depending on the coordinates format and the latitude, the next-higher precisions exceed the accuracy by a factor of somewhere between 13 and 72.)

A general rule is to give precisions approximately one-tenth the size of the object, unless there is a clear reason for additional precision. Overly precise coordinates can be misleading by implying that the object is smaller than it truly is.

There is no set way to determine object size, and the boundaries of many geographical objects are not clearly defined or not readily available. The difference rarely affects the suggested coordinates precision, so a rough size estimate is usually adequate. However, it should be noted that object size is always linear (one-dimensional), not an area measurement.

In the two most-used coordinate representations, degrees-minutes-seconds and decimal degrees, precision is, as a useful approximation,

Degrees-minutes-seconds format
Precision Diff. at equator Diff. at 30° Diff. at 45° Diff. at 60°
111 km 96.4 km 78.7 km 55.7 km
1′ 1.85 km 1.61 km 1.31 km 0.93 km
0.1′ 185 m 161 m 131 m 93 m
0.01′ 18.5 m 16.1 m 13.1 m 9.3 m
1′′ 31 m 27 m 22 m 15 m
0.1′′ 3.1 m 2.7 m 2.2 m 1.5 m
Decimal degrees format
Precision Diff. at equator Diff. at 30° Diff. at 45° Diff. at 60°
111 km 96.4 km 78.7 km 55.7 km
0.1° 11 km 9.64 km 7.87 km 5.57 km
0.01° 1.1 km 964 m 787 m 557 m
0.001° 110 m 96.4 m 78.7 m 55.7 m
0.0001° 11 m 9.64 m 7.87 m 5.57 m
0.00001° 1.1 m 96.4 cm 78.7 cm 55.7 cm

Conversions: 1 kilometre (0.621 mi), 1 metre (3.28 ft), 1 centimetre (0.394 in); 1 mile (1.61 km), 1 foot (0.305 m), 1 inch (2.54 cm)

The values in the table give distances in the east-west direction corresponding to a small change in longitude, at different latitudes. You can take the equator columns of the table as a rough guide to distances in the north-south direction that correspond to a small change in latitude, since they vary only a little bit at different latitudes. For simplicity, however, the latitude precision is commonly copied from that of the longitude.

Precision tables

[edit]

The following tables show suggested coordinates precisions for various object sizes and latitudes. Refer to the preceding section for more information about coordinates precision. To use these tables:

  • Choose one of the tables depending on whether you want degrees-minutes-seconds format or decimal degrees format
  • Find the column that is closest to the latitude of your object
  • Find the row that is closest to the size of your object
  • Note the coordinates precision at the intersection of your row and column
Usage example

Example: You want coordinates, in decimal degrees format, for Yosemite National Park, California, U.S.

  • The size of the object is roughly 70 km
  • GNIS query gives the Park's location, in decimal degrees, as: 37.8483188 (north latitude), −119.5571434 (west longitude)

To solve:

  • Choose the Decimal degrees format table
  • Find the 45° column; 37.8483188 is (slightly) closer to 45° than to 30°
  • Find the 50 km row; 70 km is closer to 50 km than to 100 km
  • Note the precision at the intersection of row and column: d.d°
  • Round to the selected precision: 37.8, −119.6

(This is a good example of a borderline case, as the latitude is quite close to 37.5°, the midpoint between 30° and 45°. If the Park were a mere 25 miles to the south, you would use the 30° column instead, yielding a different precision: d.dd°. You could opt for that precision instead, giving 37.85, −119.56. That's your call. But the table shows that more than two decimal positions would definitely be too precise for this case.)

Degrees-minutes-seconds format
30° 45° 60°
10 m d° m' s.s" or d.ddddd° [note 3] d° m' s.s"
50 m d° m' s.s" d° m' s.s" d° m' s.s" d° m' s.s"
100 m d° m' s.s" d° m' s.s" d° m' s.s" d° m' s"
500 m d° m' s" d° m' s" d° m' s" d° m' s"
1000 m
1 km
d° m' s" d° m' s" d° m' s" d° m' s"
5 km d° m' s" d° m' s" d° m' s" d° m'
10 km d° m' d° m' d° m' d° m'
50 km d° m' d° m' d° m' d° m'
100 km d° m' d° m' d° m' d° m'
500 km d° m'
1000 km
Decimal degrees format
30° 45° 60°
10 m d.ddddd° d.ddddd° d.ddddd° d.ddddd°
50 m d.ddddd° d.ddddd° d.dddd° d.dddd°
100 m d.dddd° d.dddd° d.dddd° d.dddd°
500 m d.dddd° d.dddd° d.ddd° d.ddd°
1000 m
1 km
d.ddd° d.ddd° d.ddd° d.ddd°
5 km d.ddd° d.ddd° d.dd° d.dd°
10 km d.dd° d.dd° d.dd° d.dd°
50 km d.dd° d.dd° d.d° d.d°
100 km d.d° d.d° d.d° d.d°
500 km d.d° d.d°
1000 km
  1. The tables are derived from the precision data at § Precision guidelines, above. As suggested there, they use a target resolution of one-tenth of the object size.
  2. The tables are not perfect. Some cases will yield a precision that is different from what you would get by doing the math (including trigonometry) for that specific case. This is because it is impossible to represent all cases correctly in a usable tabular format. The tables provide the correct precision for a majority of cases. Any error should be limited to one level of precision (e.g., d° m' vs. d° m' s", or d.ddd° vs. d.dddd°), which is acceptable for the purposes of Wikipedia coordinates.
  3. d.ddddd° is roughly three times more precise than d° m' s.s".

Mathematical formulas

[edit]

You can also calculate the kilometers per degree of longitude, k, using one of the following formulas (θ is the latitude, 6378.14 km is the equatorial radius, and 6356.8 km is the polar radius):

Accurate, assuming a spheroid:

Approximate:

  • Equator to latitude 25° (north or south)
  • Latitude 30° to 40°
  • Latitude 45° to pole

Coordinates from other language versions (iwcoor)

[edit]
Import of coordinates from other wikis
  • conversions are done based on external links to mapsources in other languages
  • the iwlog determines primary coordinates for articles in other languages
  • in general, primary coordinates are imported to this wiki
  • coordinates are used to replace {{coord missing}} with {{coord}} with the parameter display=title
  • dms or decimal format is kept, format=dms can be added to decimal coordinates
  • negative coordinates followed by N or E are converted to positive coordinates followed by S or W
  • coordinates are not imported if:
    • degrees are out of range (90°/180°)
    • minutes or seconds >= 60
    • region doesn't start with [a-zA-Z] [a-zA-Z]
    • type is not in list. A few are corrected (e.g. village=>city, lake=>waterbody, dam=>landmark, island=>isle). coordinates with type:state are not converted. Numbers other than population are stripped.
    • globe is present
  • scale is kept, zoom from nl: converted to scale. scale can be dropped if it's equivalent to the one determined by type
  • source is set to "xxwiki" (xx being the wiki the coordinates are imported from). An additional string can be added to differentiate one bot from others (e.g. "-x"). If source: is used in the other language, the previous element is added after a slash, e.g. source:gnis imported from xx: wiki => source:xxwiki-gnis
  • region is set to uppercase, type and scale to lowercase
  • other elements are discarded
Last updated: 16:02, 6 April 2009 (UTC)

To do list

[edit]

Tools and applications based on coordinates from Wikipedia

[edit]

Articles (and coordinates) can be found through the pages using the templates in Category:Coordinates templates

All coordinates are available for download in Wikipedia database dumps. To get the coordinates from the XML format dump of all articles (enwiki-latest-pages-articles.xml.bz2, 4 GB), the dump needs to be parsed for pages containing coordinates in the entry formats listed above. Most articles in Wikipedia conform to these formats and coordinates are easy to parse from the wikitext with regular expressions for simple character sequences. As all coordinates link to the same PHP tool, they may also be found from the SQL format table of external links (enwiki-latest-externallinks.sql.gz, 725MB). This second method will however not include all available information about the coordinates, such as their position between the article body and the title area.

There may exist some groups of articles that generate the coordinate data dynamically and are not in any of the standard entry formats, as some editors may have wished to facilitate entry of common coordinate related information, while only keeping the output similar with the existing templates. To get all such coordinates, all the articles in the database dump need to be run through a wikitext parser (such as the PHP one in MediaWiki) to expand all the templates, and the result parsed for coordinates. Alternatively, it is also possible to download the HTML generated from all the article and expanded template content (wikipedia-en-html.tar.7z, 14 GB).

Note that mass downloading individual pages from the live Wikipedia site is strongly discouraged and may lead to discontinued access.

All examples use NASA World Wind, with the Wikipedia overlay. This is purely meant as an example of using a coordinated concept for geographical coordinates.

Links to Wikipedia articles are represented by yellow rings, such as in this view of the Washington DC National Mall, using USGS aerial photos
This view of San Francisco is done using Landsat 7 satellite images. Again, note the rings that indicate Wikipedia articles
Combine radar topographic (Shuttle Radar Topography Mission) data with Landsat-7 images for full 3D visualization, as in this image of Mount Baker. Upper ring is for the Space Needle. Note also that vertical exaggeration is enabled.

View Wikipedia in Google Earth

[edit]

Project Wikipedia-World scan 11 Dumps (ca,cs,de,en,eo,es,fi,fr,nl,pt,ru) and provides:

  • dynamic Google-Earth layers in 21 languages. For instance: english Layer, español Layer
  • static Google-Earth layers in 10 language with different folders (Castles, Parks,...), Download at webkuehn.de
  • SQL-Data of all scanned coordinates

Copernix.io - View and search Wikipedia Articles on a map

[edit]

Copernix.io is a geographical search engine allowing users to search places and information from Wikipedia on a map. Users can leave the search bar empty to see all pages within an area or type a query to get subject specific information.

Some useful examples can be found at:

The main search page is at:

Visualization of Wikipedia articles with Google Maps

[edit]
  • www.geonames.org over 800,000 Wikipedia articles in 230 languages on Google maps. The placemarks include short descriptions of the displayed items, extracted from the Wikipedia articles. Webservices for full text search and reverse geocoding of Wikipedia articles.

WikiMiniAtlas JavaScript plugin

[edit]
WikiMiniAtlas displaying the KML data attached to the Bridgwater and Taunton Canal article (blue line) and the Coordinate points from the article (blue dots).

WikiMiniAtlas is a JavaScript to add to your monobook.js. It adds a draggable and zoomable (just like GoogleMaps) map to all geo-coded articles. Clickable labels with links to other geocoded articles are placed on the map to allow spatial browsing of Wikipedia. Map layers include satellite images (using Landsat7 data) with zoomlevels down to a resolution <100m, and daily updated MODIS satellite data.

WikiMiniAtlas is currently enabled on Wikipedia (by clicking on the globe () beside the coordinates).

All geodata in SQL file format

[edit]

Export multiple coordinates

[edit]

Kmlexport tool: Pages marked with multiple coordinates or categories of articles with coordinates can be exported as KML (for use in Google Earth, for example). This tool and some alternatives can be found on clicking the coordinates or by applying the {{GeoGroup}} template on a page.

The Kmlexport can be used directly or through Google Maps; see for example Colmar Pocket or Category:Capitals in Europe. Export from articles is real-time, export from categories is based on stored extractions (may be several weeks old).

KML may be converted in other formats, suitable as Points of Interest (POI) for GPS systems.

Other sources:

Coordinates search tool

[edit]

tools:~dispenser/cgi-bin/geosearch.py allows for regular expression searching on the GeoHack links in the external links table. This has the advantages of near real time information and powerful pattern matching. The following are some example queries created as a demonstration of the flexibility of the system.

Sample searches
Description MySQL Regular expression query
Coordinates imported from the CSWiki source:cswiki
Settlements whose populations are under 1,000 type:city\([0-9]{0,3}\)
South of the Antarctic Circle (approximate) =(66_[3-9]|66.[6-9]|6[7-9]|[7-9][0-9])[0-9_.]*_S_
Coordinates equivalent to 0°N 0°E / 0°N 0°E / 0; 0 =[-_0.]+[NS][-_0.]+[EW]
Coordinates in San Marino region:SM
Coordinates on Callisto globe:[Cc]allisto

To switch to other wikis, the site parameter can be added to the URL, e.g.

  • &site=commons for Commons
  • &site=pt for Portuguese Wikipedia
Searches to find problems
Problem description Python regular expression
Excess precision (6 or more decimal places) [.][0-9]{6}
Excess precision (5 decimal places) [.][0-9]{5}[^0-9]
Coordinates lacking metadata (no type or region) _[WE]_+($|&title=|\{+[0-9]\}+)
Unexpected character in parameter name params=[^&=]*?[^_a-z][a-z]*:
Unsupported parameter elevation: params=[^&=]+?elevation:
Unsupported parameter other than elevation: params=[^&=]+?([^emn]|cation|me|om):
Malformed region code params=[^&=]+?region:([^A-Z]|[A-Z]([^A-Z]|[A-Z][^_&-]|[A-Z]-[^0-9A-Z]))
Unassigned top-level region code region:(A[ABCHJKPVY]|B[CKPX]|C[BEJPQT]|D[^EJKMOZ]|E[ABDI-LUW]|F[A-HLNPQS-Z]|G[CJKOVXZ]|H[A-JLOPQSV-Z]|I[A-CF-KPU-Z]|J[^EMOP]|K[A-DFJ-LOQS-VX]|L[D-HJL-QWXZ]|M[BIJ]|N[BDHJKMNQSV-Y]|O[^M]|P[B-DIJOPQUVXZ]|Q[^A]|R[^EOSUW]|S[PQUW]|T[ABEIPQSUXY]|U[^AGMSYZ]|W[^FS]|X[^AINPSZ]|Y[^ET]|Z[^AMW])
Unexpected character in dim or scale or typesize (dim:[0-9.]*([^0-9.k_&]|k[^m]))|(scale:[0-9]*[^0-9_&])|(city[(][0-9,]*[^0-9,)])
Incomplete parameter params=[^&=]*?(dim|globe|region|scale|source|type):?(&|_|$)
Invalid type type:(?!(adm(1st|2nd|3rd)|airport|city|country|edu|event|forest|glacier|isle|landmark|mountain|pass|railwaystation|river|satellite|waterbody)($|[&_()]))
City without type: params=[^&=]*?[^:]city
College with type: other than edu [Cc]ollege[&].*?type:(?!edu)
School with type: other than edu [Ss]chool[&].*?type:(?!edu)
University with type: other than edu [Uu]niversity[&].*?type:(?!edu)
United States broadcaster with type: other than landmark [^(][KW][A-Z][A-Z][A-Z].*?params=.*?type:(?!landmark)
Station with type: other than railwaystation ailway_[Ss]tation.*?type:(?!railwaystation)
Typesize provided for type other than city type:(?!city)[^&=_]*[(]
Unusual URL formatting geohack.php[?](?!pagename=)|&language=
Tallies

WikiProject Geographical coordinates categories

[edit]

World map displaying the concentration of wikipoints

[edit]
Wikipedia-World allows generating such maps (see here)

See also

[edit]
Articles of interest
  • Coordinate system, a system that uses numbers to uniquely determine position
  • Geoinformation, created by manipulating geographic (or spatial) data (generally known by the abbreviation geodata) in a computerized system
  • Geocaching
  • Geotagging, a process of adding geographical identification metadata to various media
  • ISO 6709, standard representation of latitude, longitude and altitude for geographic point locations
  • LOC record, a means for expressing geographic location information for a domain name
Wikipedia project pages of interest
Other
Templates
Wikimedia and OpenStreetMap
Bots used in this project
WikiProject Geographical coordinates in the News

References

[edit]
[edit]
  • 3.4.2 GEO type definition to specify information related to the global positioning of the object that a vCard represents.RFC2426
  • How latitude and longitude are stored in a DNS record.RFC1876
  • Memo describing a method of adding simple geographic position information to HTTP transactions using extension headers.[2]
  • Memo describing a method of registering HTML documents with a specific geographic location through means of embedded META tags.[3]
  • Proposal to create a new IANA Time Zones registration process as a central repository for time zone names.[4]
  • WikiProject Geographical coordinates hot articles watchlist.[5][dead link]