View source for Wiki143:WikiProject Geographical coordinates

{{short description|Wikipedia subject-area collaboration}}
{{redirect|WP:GEO}} 
{{WikiProject status|active|parent=Geography|sc1=WP:GEO|sc2=WP:GEO COOR}}

'''WikiProject Geographical coordinates''' aims to better organize location information in articles containing [[Geographic coordinate system|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 [[Wikipedia:ISBN|ISBN numbers are handled]].

{{collapse top|Quick Geographical coordinates how to|width=600px}}
''NOTE: This is a concept currently under development, so this is subject to change.''

{{coord how-to}}

{{collapse bottom}}
[[File:Erioll world.svg|right|upright=1.8|thumb]]
[[File:WW washington.png|right|upright=1.8|thumb|<div class="center">[[NASA WorldWind|WorldWind]] displaying WP coordinates [[#Tools and applications based on coordinates from Wikipedia|(see applications below)]]</div>]]

== Related WikiProjects ==
WikiProject Council includes this WikiProject in its [[Wikipedia:WikiProject Council/Directory/Geographical|Geographical directory]]. This WikiProject is an offshoot of WikiProject Maps:

:'''[[Wikipedia:WikiProject Geography|WikiProject Geography]]'''
::'''[[Wikipedia:WikiProject Maps|WikiProject Maps]]'''
:::'''WikiProject Geographical coordinates'''

...and is the parent project of:

::::'''[[:de:Wikipedia:WikiProjekt Georeferenzierung/Wikipedia-World/en|Wikipedia-World]]'''

'''Other WikiProjects''' that make use of geographical coordinates include:
{{div col|colwidth=22em}}
* [[Meta:Category:Wikimaps]]
* [[Wikipedia:WikiProject Cities|WikiProject Cities]]
* [[Wikipedia:WikiProject Countries|WikiProject Countries]]
* [[Wikipedia:WikiProject Glaciers|WikiProject Glaciers]]
* [[Wikipedia:WikiProject Lakes|WikiProject Lakes]]
* [[Wikipedia:WikiProject Microformats#Geo|WikiProject Microformats Geo]]
* [[Wikipedia:WikiProject Mountains|WikiProject Mountains]]
* [[Wikipedia:WikiProject OpenStreetMap|WikiProject OpenStreetMap]]
* [[Wikipedia:WikiProject Protected areas|WikiProject Protected areas]]
* [[Wikipedia:WikiProject Rivers|WikiProject Rivers]]
* [[Wikipedia:WikiProject U.S. counties|WikiProject U.S. counties]]
* [[Wikipedia:WikiProject United States|WikiProject United States]]
{{div col end}}

==Associated Portals==
[[File:Worldmap LandAndPolitical.jpg|frameless|upright=0.45]]
'''[[portal:Atlas|The AtlasPortal]]''' is associated with WikiProject Geography.

[[File:Terrestrial globe.svg|frameless|upright=0.45]]
'''[[portal:Geography|The Geography Portal]]''' is associated with WikiProject Geography.

== Participants ==
This list has been moved to [[/Participants|its own page]].

==Goals==
# [[File:Undcstrmrc.png|30px]] Should provide a uniform markup for all geographic coordinates
# [[File:Undcstrmrc.png|30px]] Should provide a user-preferred appearance for all geographic coordinates
# [[File:Greentree.jpg|30px]] Markup should be easy and natural to use
# [[File:Check mark.svg|☑.svg]] [[File:Undcstrmrc.png|30px]] 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
# [[File:Check mark.svg|☑.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.
# [[File:Check mark.svg|☑.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 [[#View Wikipedia in Google Earth|below]]) and Google maps (see [[#Visualization of Wikipedia articles with Google Maps|below]]).
# [[File:Check mark.svg|☑.svg]] Serve as a tool for finding Wikipedia articles describing ''nearby'' locations. See also [[meta:Wikipediatlas]].
# [[File:Question dropshade.png|30px]] Adhere to existing [[Internet standards for geographic coordinates]] as far as possible{{Clarify}} such as using WGS84 for terrestrial coordinates

==Usage guidelines==

:'''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 ===
[[National mapping agency|National mapping agencies]] such as the [[Geographic Names Information System]] (GNIS), [[Ordnance Survey]] (OS), and [[Geographical Names Board of Canada]] (GNBC) are usually [[WP:RS|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 {{section link|#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==
The practical usage of coordinate markup in Wikipedia is described in [[Wikipedia:Manual of Style (dates and numbers)#Geographical coordinates|the style guide for geographical coordinates]]. For use on maps and other services, [[#Parameters|parameters]] may also be required.

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

''See also:'' [[Wikipedia:Obtaining geographic coordinates|Obtaining coordinates]]

===Templates===
{{yytop}}
{{yy|Template:User interest geographic coordinate systems}}
{{yy|Template:User WikiProject Geographical coordinates}}
{{yy|Template:User WP Geographical coordinates}}
{{yy|Template:User coord|51.477811|-0.001476|page=no}}
{{yyend}}

===Marking project-related pages on Talk page===
The template '''<nowiki>{{WikiProject Geographical coordinates}}</nowiki>''' may be added to relevant Talk pages. This adds the page to several categories and displays as:
{{WikiProject Geographical coordinates|category=no }}

==Implementation details==
===Coordinate templates===
There are two ways of specifying coordinates:

# {{tlx|coord}} – Accepts multiple data formats and supports a style sheet preference for display format, plus a [[Geo (microformat)|Geo microformat]]. <code>Coord</code> may be placed anywhere in the article source text, inline, with prose text. For example "<code>Mount Everest is at <nowiki>{{coord|27|59|16|N|86|56|40|E}}</nowiki></code>", which displays as "Mount Everest is at {{coord|27|59|16|N|86|56|40|E}}". To display coordinates at the page's top, near the article's title, in a skin-dependent way, use <code>display=title</code> (see example at [[Krasnoyarsk hydroelectric dam]]). To display both inline and top, use <code>display=inline,title</code>.
# Infoboxes – Many [[:Category:Infobox templates|infobox templates]] for places have a parameter, typically {{para|coordinates}}, for specifying a place's coordinates. The template internally uses {{tl|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, California|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 {{tl|coord}}. For an overview of choices: [[/comparison|WikiProject Geographical coordinates/comparison]].)

====Parameters====
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 [[m:Category:Wikimaps|Wikimaps]] become fully functional.

[[User:EncMstr/Coord|For example:]]
:{{tlx|coord|61.1631|-149.9721|type:landmark_globe:earth_region:US-AK_scale:150000_source:gnis|5=name=Kulis Air National Guard Base}} displays {{coord|61.1631|-149.9721|type:landmark_region:US-AK_scale:150000_source:gnis|name=Kulis Air National Guard Base}}
It has
* type:landmark
* globe:earth
* region:US-AK
* scale:150000
* source:gnis

===== type:''T'' =====
{{shortcut|WP:COORD TYPE}}
{{/type:}}

===== dim:''D'' =====
{{/dim:}}

===== scale:''N'' =====
{{shortcut|WP:COORD SCALE}}
{{/scale:}}

===== region:''R'' =====
{{shortcut|WP:COORD REGION}}
{{/region:}}

===== globe:''G'' =====
{{/globe:}}

===== source:''S'' =====
{{shortcut|WP:COORD SOURCE}}
{{/source:}}

==== Name ====
{{tl|coord}} takes <code>|name=''name''</code>

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 [[:meta:WikiMiniAtlas|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.

==== <span id="Display">Display preferences</span> ====
{{UF-coord-classes}}

==== Format ====
* <code>format=dec</code> will reformat the coordinates to <span style="text-decoration:underline;">decimal degrees</span> for all readers.
* <code>format=dms</code> will reformat the coordinates to <span style="text-decoration:underline;">degrees | minutes | seconds (dms)</span> format for all readers.

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

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 <code>lat_d = 45.678 | long_d = -123.456</code> and omission of the remaining parameters.

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

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

=== Linear features ===
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===
See [[Wikipedia:Obtaining geographic coordinates|Obtaining geographic coordinates]]

''See also:'' [[:Category:Articles needing coordinates]], [[:de:Wikipedia:WikiProjekt Georeferenzierung/Wikipedia-World/en#Maybe-Checker|Maybe-Checker]]

===Geodetic system===
All coordinates specified through {{tl|coord}} must be referenced to [[World Geodetic System|WGS84]], or an equivalent datum. WGS84 is required for some of the conversions done by the geohack extension.

[[British national grid reference system|British national grid references]] of the Ordnance Survey use its own [[British national grid reference system|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 {{tl|oscoor}} tags. However, OSGB36 latitude/longitude coordinates should not be used anywhere in Wikipedia; please use WGS84 lat/long instead.

===<span class="anchor" id="Precision"></span>Precision guidelines===
{{shortcut|WP:OPCOORD}}
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,

{|
|- style="vertical-align:top;"
|
{| class="wikitable" style="text-align:right;"
|+ Degrees-minutes-seconds format
!Precision
!Diff. at equator
!Diff. at 30°
!Diff. at 45°
!Diff. at 60°
|-
|1°||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
|}
||
{| class="wikitable" style="text-align:right; margin-left:20px;"
|+ Decimal degrees format
!Precision
!Diff. at equator
!Diff. at 30°
!Diff. at 45°
!Diff. at 60°
|-
|1°||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: {{convert|1|km|mi|3}}, {{convert|1|m|ft|2}}, {{convert|1|cm|in|3}};
{{convert|1|mi|km|2}}, {{convert|1|ft|m|3}}, {{convert|1|in|cm|2}}

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====
{{shortcut|WP:COORDPREC}}
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
The colors on the table serve only to distinguish consecutive precision levels.
{{Collapse top|title=Usage example|bg=#fcfce6}}
Example: You want coordinates, in decimal degrees format, for Yosemite National Park, California, U.S.
* The size of the object is roughly 70 km
* [https://geonames.usgs.gov/apex/f?p=138:1:0::::: 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°
* [[Rounding|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.)
{{Collapse bottom}}
<!-- 
     BACKGROUND COLORS: 
     #f2f2f2 - gray for the object size header columns (latitude header rows have this color by default)
     #b3d1ff - blue for data cells
     #fcfce6 - yellow for data cells
-->
{|
|- style="vertical-align:middle;"
|
{| class="wikitable" style="text-align:left;"
|+ Degrees-minutes-seconds format
!
!0°
!30°
!45°
!60°
|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''10 m'''
|colspan="3" style="background:#f2f2f2; text-align:center;"|d° m' s.s" or d.ddddd° <sup>[note 3]</sup>
|style="background:#b3d1ff;"|d° m' s.s"

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''50 m'''
||d° m' s.s"  ||d° m' s.s"  ||d° m' s.s"  ||d° m' s.s"

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''100 m'''
||d° m' s.s"  ||d° m' s.s"  ||d° m' s.s"  ||style="background:#fcfce6;"|d° m' s"

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''500 m'''
||d° m' s"  ||d° m' s"  ||d° m' s"  ||d° m' s"

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''1000 m<br>1 km'''
||d° m' s"  ||d° m' s"  ||d° m' s"  ||d° m' s"

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''5 km'''
||d° m' s"  ||d° m' s"  ||d° m' s"  ||style="background:#b3d1ff;"|d° m'

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''10 km'''
||d° m'  ||d° m'  ||d° m'  ||d° m'

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''50 km'''
||d° m'  ||d° m'  ||d° m'  ||d° m'

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''100 km'''
||d° m'  ||d° m'  ||d° m'  ||d° m'

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''500 km''' ||style="background:#b3d1ff;"|d° m' ||d° ||d° ||d°

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''1000 km'''
||d°  ||d°  ||d°  ||d°
|}
||
{| class="wikitable" style="text-align:left; margin-left:20px;"
|+ Decimal degrees format
!
!0°
!30°
!45°
!60°
|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''10 m'''
||d.ddddd°  ||d.ddddd°  ||d.ddddd°  ||d.ddddd°

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''50 m'''
||d.ddddd°  ||d.ddddd°  ||style="background:#b3d1ff;"|d.dddd°  ||style="background:#b3d1ff;"|d.dddd°

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''100 m'''
||d.dddd°  ||d.dddd°  ||d.dddd°  ||d.dddd°

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''500 m'''
||d.dddd°  ||d.dddd°  ||style="background:#fcfce6;"|d.ddd°  ||style="background:#fcfce6;"|d.ddd°

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''1000 m<br>1 km'''
||d.ddd°  ||d.ddd°  ||d.ddd°  ||d.ddd°

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''5 km'''
||d.ddd°  ||d.ddd°  ||style="background:#b3d1ff;"|d.dd°  ||style="background:#b3d1ff;"|d.dd°

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''10 km'''
||d.dd°  ||d.dd°  ||d.dd°  ||d.dd°

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''50 km'''
||d.dd°  ||d.dd°  ||style="background:#fcfce6;"|d.d°  ||style="background:#fcfce6;"|d.d°

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''100 km'''
||d.d°  ||d.d°  ||d.d°  ||d.d°

|- style="background:#fcfce6;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''500 km'''
||d.d°  ||d.d°  ||style="background:#b3d1ff;"|d°  ||style="background:#b3d1ff;"|d°

|- style="background:#b3d1ff;"
|style="background:#f2f2f2; text-align:right; padding-right:10px;"|'''1000 km'''
||d°  ||d°  ||d°  ||d°
|}
|}
#{{smaller|The tables are derived from the precision data at {{section link||Precision guidelines}}, above. As suggested there, they use a target resolution of one-tenth of the object size.}}
#{{smaller|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°&nbsp;m'''' vs. '''d°&nbsp;m'&nbsp;s"''', or '''d.ddd°''' vs. '''d.dddd°'''), which is acceptable for the purposes of Wikipedia coordinates.}}
#{{smaller|'''d.ddddd°''' is roughly three times more precise than '''d° m' s.s"'''.}}

====Mathematical formulas====
You can also calculate the kilometers per degree of longitude, ''k,'' using one of the following formulas (θ is the latitude, 6378.14&nbsp;km is the [[Earth radius|equatorial radius]], and 6356.8&nbsp;km is the polar radius):

Accurate, assuming a [[spheroid]]: 
* <math>k = \frac{\pi}{180}\cos(\theta)\sqrt{\frac{(6378.14^2\cos\theta)^2+(6356.8^2\sin\theta)^2}{(6378.14\cos\theta)^2+(6356.8\sin\theta)^2}}</math>

Approximate: 
* <math>k = 111.3\cos\theta\,</math>  Equator to latitude 25° (north or south)
* <math>k = 111.2\cos\theta\,</math>  Latitude 30° to 40°
* <math>k = 111.1\cos\theta\,</math>  Latitude 45° to pole

=== Coordinates from other language versions (iwcoor) ===
{| class="wikitable"
|-
! Import of coordinates from other wikis
|-
|
* conversions are done based on external links to mapsources in other languages
* the [[tools:~dispenser/view/File viewer#log:iwcoord-enwiki-Coord missing.log|iwlog]] determines primary coordinates for articles in other languages
* in general, primary coordinates are imported to this wiki
* coordinates are used to replace {{tl|coord missing}} with {{tl|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 [[Wikipedia:GEO#type:T|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==
{{To do|list=Wikipedia talk:WikiProject Geographical coordinates/to do|nocats=yes|nopreload=yes}}

==Tools and applications based on coordinates from Wikipedia==
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 download|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 [[Parsing|parsed]] for pages containing coordinates in the [[#Coordinate templates (currently used instead of geo tag)|entry formats listed above]]. Most articles in Wikipedia conform to these formats and coordinates are easy to parse from the [[wikitext]] with [[regular expression]]s for simple character sequences. As all coordinates link to [[Template:Coor URL|the same PHP tool]], they may also be found from the [[SQL]] format [[:mw:Externallinks table|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 [[Wikipedia:Technical FAQ#Is it possible to download the contents of Wikipedia?|may lead to discontinued access]].

=== [[NASA World Wind]] Samples ===
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.

{|
|- style="vertical-align:top;"
| [[File:WW_washington.png|thumb|upright=1.15|none|Links to Wikipedia articles are represented by yellow rings, such as in this view of the [[Washington, D.C.|Washington DC]] National Mall, using [[United States Geological Survey|USGS]] aerial photos]]
| [[File:WW_sanfrancisco.png|thumb|upright=1.15|none|This view of [[San Francisco, California|San Francisco]] is done using [[Landsat 7]] satellite images. Again, note the rings that indicate Wikipedia articles]]
| [[File:WW_mountbaker.png|thumb|upright=1.15|none|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===
Project '''[[:de:Wikipedia:WikiProjekt Georeferenzierung/Wikipedia-World/en|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: [http://toolserver.org/~kolossos/world-link.php?lang=en english Layer], [http://toolserver.org/~kolossos/world-link.php?lang=es español Layer]
* static Google-Earth layers in 10 language with different folders (Castles, Parks,...), Download at [http://www.webkuehn.de/hobbys/wikipedia/geokoordinaten/index_en.htm webkuehn.de]
* SQL-Data of all scanned coordinates

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

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:
* [http://copernix.io/about Copernix examples and about ]
The main search page is at:
* [http://copernix.io Copernix.io]

===Visualization of Wikipedia articles with Google Maps===
* [http://www.geonames.org/wikipedia.html 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===
[[File:WikiMiniAtlas_KML_screenshot.png|thumb|upright=1.15|WikiMiniAtlas displaying the KML data attached to the [[Bridgwater and Taunton Canal]] article (blue line) and the Coordinate points from the article (blue dots).]]
[[meta:WikiMiniAtlas|WikiMiniAtlas]] is a JavaScript to add to your [[Special:Mypage/monobook.js|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 [[:File:MiniWikiAtlas screenshot 2.png|satellite images]] (using Landsat7 data) with zoomlevels down to a resolution <100m, and [[:File:MiniWikiAtlas screenshot 3.png|daily updated]] MODIS satellite data.

WikiMiniAtlas is currently enabled on Wikipedia (by clicking on the globe ([[File:Erioll world.svg|18px| ]]) beside the coordinates).

===All geodata in SQL file format===
* Project '''[[:de:Wikipedia:WikiProjekt Georeferenzierung/Wikipedia-World/en|Wikipedia-World]]''', provides the complete database for download in [[SQL]]-file format.

=== Export multiple coordinates ===
[[tools:~para/cgi-bin/kmlexport|Kmlexport]] tool: Pages marked with multiple coordinates or categories of articles with coordinates can be exported as [[Keyhole Markup Language|KML]] (for use in Google Earth, for example). This tool and some alternatives can be found on clicking the coordinates or by applying the {{tl|GeoGroup}} template on a page.

The Kmlexport can be used directly or through Google Maps; see for example [http://maps.google.com/maps?q=http://toolserver.org/~para/cgi-bin/kmlexport?article=Colmar_Pocket Colmar Pocket] or [http://maps.google.com/maps?q=http://toolserver.org/~para/cgi-bin/kmlexport?article=Category:Capitals_in_Europe 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 [[Point of interest|Points of Interest]] (POI) for [[Global Positioning System|GPS]] systems.

Other sources:
* [http://www.wikitude.org Wikitude] provides coordinates as KML or [[TomTom]] POI format.

====Coordinates search tool====
[[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.

{{Ed right2|Wikipedia:WikiProject_Geographical_coordinates/coordinates_search_tool}}

{{/coordinates search tool}}

===WikiProject Geographical coordinates categories===
<categorytree>WikiProject Geographical coordinates</categorytree>

===World map displaying the concentration of wikipoints===
[[File:Imageworld-artphp3.png|thumb|upright=2.7|left|<div class="center">[[:de:Wikipedia:WikiProjekt Georeferenzierung/Wikipedia-World/en|Wikipedia-World]] allows generating such maps (see [[:de:Wikipedia:WikiProjekt Georeferenzierung/Wikipedia-World/en#World map with a representation of the concentration of wikipoints|here]])</div>]]
{{-}}

==See also==
;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
* [[Wikipedia:Categorization of location|Categorization of location]], proposal to generate lists of articles about nearby locations from a given Wikipedia article
* [[Wikipedia:Coordinate-referenced map templates|Coordinate-referenced map templates]], inactive guideline proposal for using coordinate-referenced map templates to generate maps in Wikipedia articles
* [[Wikipedia:Geographic references|Geographic references]], a list of sources used in the creation of encyclopedia articles on various geographic topics and locations
* [[Wikipedia:Geonotice|Geonotice]], location targeted messages using geocoordiates to announce upcoming Wikipedia meetups and local events
* [[Wikipedia:How to add geocodes to articles|How to add geocodes to articles]], a short guide to how to add geographic coordinate tags to Wikipedia articles
* [[User:EncMstr/Coord|How to add geocodes to articles by User:EncMstr]], EncMstr's guide on how to enter coordinate data using {{tlx|coord}}
* [[Wikipedia:Manual of Style (dates and numbers)#Geographical coordinates|MoS Geographical coordinates]], Official style guideline on geographical coordinates
* [[:Help:Mobile access|Mobile access]], How to use a mobile phone to search for geotagged Wikipedia articles near your current location
* [[Wikipedia:Obtaining geographic coordinates|Obtaining geographic coordinates]], listing various ways on how to obtain geographic coordinates for use in an article.
* [[Wikipedia:Version 1.0 Editorial Team/WPPlaces#Wikipedia:WikiProject Geographical coordinates|Version_1.0_Editorial_Team/WPPlaces]], Version 1.0 Editorial Team contact results with WikiProject Geographical coordinates
* [[Wikipedia:WikiProject Maps/Source materials|WikiProject Maps/Source materials]], list of free maps for use in creating geographical maps for Wikipedia.

;Other
* [[Commons:Commons:Geocoding]]
* [[meta:Geographical data]]
* [[meta:WikiGPS]]
* [[meta:Wikipediatlas]]
* [[meta:WikiProjects Geographical coordinates]]
* [http://lists.wikimedia.org/pipermail/wikitech-l/2005-March/015851.html Wikitech-l Extensions for handling geographical coordinates]

;Templates
* [[Template:Coor Maidenhead]] (displays geographical coordinates as [[Maidenhead Locator System|Maidenhead grid squares]])
* [[Template:Canada NTS Grid]] (displays designator for [[National Topographic System]] map sheet containing specified geographical coordinates)
* [[Template:Sky]] (the same idea for astronomical objects)

;Wikimedia and OpenStreetMap
* Announcement http://lists.wikimedia.org/pipermail/wikitech-l/2009-April/042483.html
* [[Wikipedia:Wikipedia Signpost/2009-04-06/Interactive maps|Signpost/2009-04-06/Interactive maps]], "a new initiative is underway to make OpenStreetMap available as interactive maps within Wikipedia"
* [[mw:Project:Developer meet-up 2009/Notes/Mapping]]
* [[m:OpenStreetMap]], [[m:Talk:OpenStreetMap]]
* Maps-l: [http://lists.wikimedia.org/pipermail/maps-l/ Archives], [http://lists.wikimedia.org/pipermail/maps-l/{{CURRENTYEAR}}-{{CURRENTMONTHNAME}}/date.html Current month]
** [https://wiki.openstreetmap.org/wiki/Collaboration_with_Wikipedia wiki.openstreetmap.org/wiki/Collaboration with Wikipedia]

;Bots used in this project
* [[Wikipedia talk:Bot Approvals Group/Archive 7#Clarification for User:The Anomebot2 activities|User:The Anomebot2]] geo tagging

; WikiProject Geographical coordinates in the News
* [[Wikipedia:Wikipedia Signpost/2008-06-02/Dispatches|Signpost/2008-06-02]], in [[Wikipedia:Manual of Style (dates and numbers)#Geographical coordinates|MoS geographical coordinates]], [http://en.wikipedia.org/w/index.php?title=Wikipedia:Manual_of_Style_%28dates_and_numbers%29&diff=213665425&oldid=213594423 This] section was restored with an edit summary to see [[WP:GEO]].
* [[Wikipedia:Wikipedia Signpost/2009-09-14/News and notes|Signpost/2009-09-14]], "Another milestone was reached in the English Wikipedia, with more than 500,000 articles now providing geographic coordinates based on the {{tl|coord}} template, according to the [http://toolserver.org/~jarry/templatecount/index.php template transclusion counter]. WikiProject Geographical coordinates, however, knows of at least another 169,000 articles which ideally should have coordinates; these are listed in the category tree [[:Category:Articles missing geocoordinate data by country]]. See [[Wikipedia:How to add geocodes to articles]] for more information. "
* [[Wikipedia:Wikipedia Signpost/2010-03-22/In the news|Signpost/2010-03-22]],New commercial Wikipedia iPhone app "Nearby" provides a map with links to [[WP:GEO|geotagged]] Wikipedia articles in the vicinity.
* [[Wikipedia:Wikipedia Signpost/2010-05-03/News and notes|Signpost/2010-05-03]], "The Wikimedia Foundation has updated the official "Wikipedia Mobile" iPhone app, [[Wikipedia:Wikipedia Signpost/2009-08-24/Technology report#Wikipedia iPhone app|first released in August 2009]]. New features include an improved layout, bookmarkable articles, and plotting geolocated articles near to the user's location on a map. The app is a [http://itunes.apple.com/us/app/wikipedia-mobile/id324715238 free download] from the App Store."
* [[Wikipedia:Wikipedia Signpost/2010-11-01/News and notes|Signpost/2010-11-01]], "One million geocoordinates: Last week, the number of geographical coordinates on the English Wikipedia<!--mainspace--> [[Wikipedia talk:WikiProject Geographical coordinates#1 million milestone|surpassed one million]], in around 620,000 articles. At the same time, around 180,000 articles were [[:Category:All articles needing coordinates|marked as needing coordinates]] (which would correspond to a completion rate of 78% if no more geocodable articles were added). In September 2009, the milestone of half a million articles with geocoordinates had been reached (see [[Wikipedia:Wikipedia Signpost/2009-09-14/News and notes#Milestones|''Signpost'' coverage]]). In related news, links to display interactive [[OpenStreetMap]] maps within articles were recently enabled by default on the German and Norwegian (Bokmål/Rikmål) Wikipedias (to see an example, click "Karte" on the top right of [[:de:Berlin]]), the fruit of a collaboration that had been begun last year, supported by the German Wikimedia chapter (see [[Wikipedia:Wikipedia Signpost/2009-04-06/Interactive maps|''Signpost'' coverage]])."

==References==
{{Reflist}}

==External links==
* 3.4.2 GEO type definition to specify information related to the global positioning of the object that a [[vCard]] represents.[http://www.faqs.org/rfcs/rfc2426.html RFC2426]
* How latitude and longitude are stored in a [[Domain Name System|DNS]] record.[http://www.faqs.org/rfcs/rfc1876.html RFC1876]
* Memo describing a method of adding simple geographic position information to HTTP transactions using extension headers.[https://tools.ietf.org/html/draft-daviel-http-geo-header-04]
* Memo describing a method of registering HTML documents with a specific geographic location through means of embedded META tags.[https://tools.ietf.org/html/draft-daviel-html-geo-tag-06]
* Proposal to create a new IANA [[tz database|Time Zones]] registration process as a central repository for time zone names.[http://tools.ietf.org/html/draft-royer-timezone-registry-01]
* WikiProject Geographical coordinates hot articles watchlist.[http://toolserver.org/~tim1357/cgi-bin/wikiproject_watchlist.py?template=WikiProject_Geographical_coordinates]{{Dead link|date=July 2018}}

{{Wikipedia policies and guidelines}}
{{WikiProject Footer}}

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[[Category:Wikipedia maps|Geographical coordinates]]
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