View source for Commons:Geocoding

{{Header|Lang-GEO|COM:GEO|COM:GC}}
<div style="background-color: yellow;">'''''Warning:''' As of March 2019, KML/Commons-on-OSM results appear be significantly broken, with most results hidden.  This can make debugging frustrating.  See [[Commons talk:Geocoding]]/[[phab:T226710|T226710]]''.</div>
On Wikimedia Commons, [[w:geocoding|geocoding]] is the practice of attaching geographic location information to media. When we geocode media on commons we identify the latitude and longitude from '''where the media was recorded''' and attach it to the description page using a {{tl|Location}} template. For jpeg images, geodata can also be stored in the image [[Commons:Manipulating_meta_data#Purpose_for_using_Exif_at_Commons|Exif]].

<!--At some point in the future this data will enable useful features such as location based browsing and overlaying images on maps.-->
[[Image:wikiminiatlas_commons_standalone_2.png|thumb|250px|Geocoded images on a [https://wma.wmflabs.org/ worldmap]]]
[[File:Geolocated images in Wikimedia Commons 2015-01-07.png|thumb|right|250px|As of February 2015, 5.2M Wikimedia Commons images are geolocated.]]
Media that is geocoded can be found in [[:Category:Media with locations]]. 

You can find coordinates for untagged pictures in: [[:Category:Location possible]]. If you see an image that needs geotags, you can add {{tl|Location possible}}.

==Geocoding media on Commons==
Geocoding is easy and only takes a couple of steps. All coordinates should be referenced to the [[:en:WGS84]] datum, the one supported by GPS systems and Google Maps. References taken from printed maps are unlikely to use this datum, and lead to inaccuracies in the order of hundreds of metres. National Grid reference systems use a local datum so will provide the wrong result.

On Commons we record '''the location of the camera''' as accurately as we can. Pictures can be geocoded in the camera, or in your own computer, or after uploading. Some of the tools can be activated in the "gadget" tab of [[Special:Preferences]]:
* {{MediaWiki:Gadget-Geotoolbox}}
* {{MediaWiki:Gadget-Geocodecattodo}}

==Automatic procedures==
GPS or other automated methods can be especially useful in rural locations without landmarks which can be easily recognized in the aerial images.  If your camera has a built-in ''GPS receiver'' (as most smartphone camera phones do) then your work is already done.  Since November 2011, the Upload Wizard adds the proper Geocoding Templates from the GPS data stored in your images.  For pictures not uploaded through the Wizard, {{tl|GPS EXIF}} can be added to summon a bot to code them.

You can also use a separate GPS receiver to record the location while you are recording the media, and use computer software to merge the locations into the image files.  Such software uses the camera time tag in the image file to look up the coordinates from the GPS. For accurate results, the camera time must be correct or the time error entered manually. The time error can be monitored by photographing the time displayed by the GPS.  Errors caused by spotty GPS coverage can be adjusted by the same tools that are used for manual geocoding, though more easily since you already have an approximate position.  

By 2020 many cameras had a feature whereby they can connect to a smartphone via Wi-Fi or Bluetooth. The phone can control the camera remotely, transfer pictures from the camera, or transfer geocoordinates to the camera for insertion in the EXIF data of the picture. Some can only add coordinates after the fact, using a GPS log feature, and some can do it on the fly.

=== Adding Geotags before uploading ===
Some software, such as [https://microsoft-photo-info.en.softonic.com/ Microsoft Pro Photo Tools] or {{W|darktable}}, allow you to add geographical information to images from a map.  The upload wizard will also recognize these tags.  These programs cannot add camera directions, but other programs such as [http://www.geosetter.de/en Geosetter] can insert metadata including: geographic coordinates of the location shooting, camera direction, and the name of the exact location.  

If your camera has accidentally tagged your images with completely wrong geodata, you can remove them on a batch of pictures by using [http://freeweb.siol.net/hrastni3/foto/exif/exiftoolgui.htm ExifToolGUI]. It uses ExifTool that is also installed by Geosetter mentioned above.

===Locator-tool===
The [[Commons:Locator-tool]] allows to quickly add {{tl|Location}} / {{tl|Object location}} information to already uploaded images. You can specify a list of images to geocode (e.g., by querying a category), select their respective location on a map and let the {{tl|Location}} be added/updated automatically.

== Manual procedures ==
{| class="wikitable" style="clear:right;float:right;margin:0 0 1em 1em;"
|+ Zoom levels 
|-
!<abbr title="Open Street Map">OSM</abbr>
!scale
|-
|<kbd>19</kbd>
|style="text-align:center"|<small>''unavailable''</small>
|-
|<kbd>18</kbd>||<kbd>&nbsp; &nbsp; 1000</kbd>
|-
|<kbd>17</kbd>||<kbd>&nbsp; &nbsp; 3000</kbd>
|-
|<kbd style="background-color:cyan">'''16'''</kbd>||<kbd style="background-color:cyan">&nbsp; &nbsp; '''5000'''</kbd>
|-
|<kbd>15</kbd>||<kbd>&nbsp; &nbsp;10000</kbd>
|-
|<kbd>14</kbd>||<kbd>&nbsp; &nbsp;30000</kbd>
|-
|<kbd>13</kbd>||<kbd>&nbsp; &nbsp;50000</kbd>
|-
|<kbd>12</kbd>||<kbd> &nbsp; 100000</kbd>
|-
|<kbd>11</kbd>||<kbd> &nbsp; 300000</kbd>
|-
|<kbd>10</kbd>||<kbd> &nbsp; 500000</kbd>
|-
|<kbd>&nbsp;9</kbd>||<kbd>&nbsp;1000000</kbd>
|-
|<kbd>&nbsp;8</kbd>||<kbd>&nbsp;2000000</kbd>
|-
|<kbd>&nbsp;7</kbd>||<kbd>&nbsp;3000000</kbd>
|-
|<kbd>&nbsp;6</kbd>||<kbd>&nbsp;5000000</kbd>
|-
|<kbd>&nbsp;5</kbd>||<kbd>10000000</kbd>
|-
|<kbd>&nbsp;4</kbd>||<kbd>30000000</kbd>
|-
|<kbd>&nbsp;3</kbd>||<kbd>50000000</kbd>
|}

The easiest way to identify the location in urban areas is to use an online mapping site with aerial imaging such as: 

=== GeoLocator tool ===

* https://tools.freeside.sk/geolocator/geolocator.html ([[w:User:Teslaton/Tools/GeoLocator|project page]])

Steps to obtain coordinates and build appropriate location tag:
# find your location on embedded map (move/zoom/search it as needed)
# place location marker on most exact location ([Alt+click] over your location, or by dragging a marker)
# define [[#Parameters|heading]] (camera view direction) from that location ([Shift+mouse move]/[Shift+click])
# copy resulting <code><nowiki>{{location}}</nowiki></code>  markup

Steps to update an existing location tag (to improve location or to add heading):
# paste existing location tag into query box and press Apply. Tag gets parsed and location will appear on a map.
# update location marker to more exact location (by dragging it or by [Alt+click] over new location)
# define [[#Parameters|heading]] (camera view direction) from that location ([Shift+mouse move]/[Shift+click])
# copy resulting <code><nowiki>{{location}}</nowiki></code>  markup back

=== Bing Maps ===
Right click where the exact location is and you have the coordinates. Paste into the Location template.

=== OpenStreetMap ===
# Open a new browser tab/window and load [https://www.openstreetmap.org/ https://www.openstreetmap.org/].
# Search for the correct location; you probably want to zoom in to make this easier.
# Right-click on the exact location the media was recorded. A little pop-up menu opens there. From the pop-up menu, select ''Show address''.
<!-- # The visible part of the map changes (a bit). In the [[w:Address bar|address bar]] of your browser tab/window, you can find the coordinates of the selected position. You can copy them from there.

For example, if you have clicked on the [[w:Brandenburg Gate|Brandenburg Gate]] on the map in step (3), the adress bar now reads: <code>https://www.openstreetmap.org/#map=17/52.5163/13.3777</code>
* 52.5163 is the latitude
* 13.3777 is the longitude
* (Please ignore the first number (17); this is just the zoom level and not used for geocoding.)
So you can add to the image page:
{{tlc|Location|52.5163|13.3777}}
For details on using the {{tlc|Location}} template, please see below. -->

=== Google Maps ===
# Open a new browser tab/window and load [https://maps.google.com/ https://maps.google.com/].
# Search for the correct location (zoom in, Satellite mode is suggested). 
# Right-click on the exact location the media was recorded and select ''Center map here''
# Click the link icon in the left sidebar
# Copy the link in the top box (do not click ''short url'')
# Use the [[User:Dschwen/Coordinate conversion helper|Coordinate conversion helper]] to insert the coordinates on the image page (add a heading such as "N","SE","NNW")
#:Check the page for instructions on installing and using it.

=== Google Earth ===
* If you have [[w:Google Earth|Google Earth]], a tool for geotagging can be installed: [http://www.alder-digital.de/wiki/images/Ald-Hjl-Koord-en.kmz '''Ald-Hjl-Koord-en.kmz''']. A crosshair will appear in the middle of the Google Earth screen. Place the crosshair exactly over the camera location by moving the view, and click on it. The location template can be copied from the window that opens. (Please deactivate the tool if unused.)
* If you have coordinates in a [[w:Keyhole Markup Language|KML]] file (such as created in Google Earth and exported with "Save As" or "Copy", or aided by [[w:Picasa|Picasa]]), the '''[https://tools.wmflabs.org/geocommons/kmlconvert.php kmlconvert]''' tool can be used to convert the coordinates to Commons templates. This method is suitable for geocoding a series of images.

''See [[:en:Wikipedia:Obtaining geographic coordinates]] for more information.''

==Adding a location template==
The use of the following templates is encouraged:
* {{tl|Location}} for camera locations
* {{tl|Object location}} same idea for ''object'' instead of ''camera'' locations

'''Do not simply invent your own new templates or copy geocoding templates from other wikis without discussion. Doing so can break the automation that reads and uses the geocoding. Commons geocoding needs are also not the same as those of other projects.'''  Note that you also should not create your own wrappers around {{tl|Location}} or {{tl|Object location}}; this will break the automation as well. Just call one of the templates directly from the image description page.

Simply add {{tlc|Location|lat|long}} to the image page, filling in the lat and long from the procedure above. If the image page has an {{tlc|Information}} template, or similar, the {{tlc|Location}} template should come immediately after it. For example, the result for {{tlc|Location|37.51136|-77.602615}} will look like this:
{{Location|37.51136|-77.602615}}

Alternatively, to use degrees, minutes and seconds instead of decimal degrees, add {{tlc|location|lat deg|lat min|lat sec|NS|long deg|long min|long sec|EW}} to the image page, filling in the lat and long. For example, the result for {{tlc|Location|37|30|40.9|N|77|36|9.41|W}} will look like this:
{{Location|37|30|40.9|N|77|36|9.41|W}}

[[Image:Compass Card.png|thumb|Compass points]]

=== Parameters ===
{{Main|Template:Location#Template parameters|Template:Object location#Template parameters}}
Wikipedia geocoding often uses [[:w:Wikipedia:WikiProject Geographical coordinates#Parameters|parameters]] after the coordinates to give more information about the location, but some of them are not useful here. 

* ''type'' and ''scale'' - The defaults are <code style="font-size:smaller">type:landmark_scale:5000</code>. See [[#Manual_procedures|above]] for other values of ''scale'', and the corresponding initial <abbr title="Open Street Map">OSM</abbr> zoom when opened via [[toollabs:geohack|GeoHack]]. An explicitly given ''scale'' trumps an implicit ''scale'' value associated with an also given ''type''. {{small|TBD: list of ''type'' values and their corresponding ''scale'' defaults for commons, dewiki, and enwiki for comparison.}} 
* ''dim'' - The ''<abbr title="dimension">dim</abbr>'' in meters can be used for bigger areas in {{tlx|object location}}, e.g., <code style="font-size:smaller">type:mountain_dim:2000_scale:10000_region:PL-MA</code>. {{small|TBD: document the effect (if any) of ''dim''.}}
* ''region'' - If given the region {{best current practice|must}} be an <span class="plainlinks">[https://en.wikipedia.org/w/index.php?title=Special%3APrefixIndex&prefix=ISO+3166-2%3A&namespace=0&hideredirects=1&stripprefix=1 ISO 3166-2]</span> code, e.g., US-CA for [[:en:California|California]]. The ''region'' can be used for the [[toollabs:geohack|GeoHack]] selection of regional map services.
* ''heading'' - Used to indicate the direction the camera was pointing at. It is given as degree values ''0-360'' (clockwise with north as 0) or a compass point abbreviation as defined in [[:w:Boxing the compass]]. (Example: ''heading:NW'') Compass overlay can be displayed on Google Maps or in Google Earth to help find the correct heading, and the [http://tools.freeside.sk/geolocator/geolocator.html GeoLocator] tool allows interactive picking of correct heading on a map as part of metadata authoring.

===Precision===
At the moment the named parameter <code style="font-size:smaller">prec=1000</code> (example) in {{tl|location}} or {{tl|object location}} is only used to truncate the displayed coordinates on the page (category, file, or gallery.) The [[toollabs:geohack|GeoHack]] map service still gets the full coordinates as specified without indication of the desired precision. The effect depends on the position (see below) and on the display style (decimal <samp>ddd.nnnnnn</samp> vs. <samp>ddd°mm′ss.nnn″</samp>), e.g., <code style="font-size:smaller">prec=1000</code> removes the <samp>ss.nnn″</samp> (seconds) display everywhere on earth, while <code style="font-size:smaller">prec=100</code> only removes <samp>.nnn</samp> (decimal fractions of seconds.) 

The linear measurement of a longitudinal angle varies according to latitude. If we are aiming to a precision of about 0.5–1&nbsp;m, then it is appropriate to use decimal degrees with 5 decimal places. For the minute/second format, seconds with 1 decimal place will similarly give precision of about 1.5–3 meters of real earth surface. More decimal places have not sense because available maps and navigations are not more precise.  
{| class="wikitable"
|+ Length equivalent of longitudinal degree at selected latitudes in km
|-
!width="100"|Latitude
!width="150"|Town
!width="100"|Degree °
!width="100"|Minute ′
!width="100"|Second ″
!width="100"|Decimal Degree at 4 dp
|-
|60||[[Saint Petersburg]]||55.65&nbsp;km||0.927&nbsp;km||15.42&nbsp;m ||5.56&nbsp;m
|-
|51° 28′ 38″ N||[[:en:Greenwich|Greenwich]]||69.29&nbsp;km||1.155&nbsp;km||19.24&nbsp;m||6.93&nbsp;m
|-
|45||[[Bordeaux]]||78.7&nbsp;km||1.31&nbsp;km||21.86&nbsp;m||7.87&nbsp;m
|-
|30||[[New Orleans]]||96.39&nbsp;km||1.61&nbsp;km||26.77&nbsp;m||9.63&nbsp;m
|-
|0||[[Quito]]||111.3&nbsp;km ||1.855&nbsp;km ||30.92&nbsp;m || 11.13&nbsp;m
|}

''Note that latitudinal degrees do not vary significantly across the Earth, having a surface precision of 1" = 31 m or 0.0001° = 11 m. See [[:en:Geographic coordinate system]] for more information.''
<!--Latitudes expressed as degrees with 5 decimal places have a surface precision of about 1.1 meters; with four decimal digits the precision is about 11 m. (Longitudes have equal or finer resolution than this, depending on latitude, so the precision of latitude representation is the dominant error).-->

==Stats==

For actual number of geocoded files, see [[:category:Media with locations]].

<gallery perrow="5">
File:Commons geocoding graph.svg|Geocoded images on Commons, March 2007 - mid 2010
File:Geolocated images in Wikimedia Commons 2012-01-21.png|Geolocated images in Wikimedia Commons 2012-01-21
File:Geolocated images in Wikimedia Commons 2014-02-21.png|Geolocated images in Wikimedia Commons 2014-02-21 
File:Geolocated images in Wikimedia Commons 2015-01-07.png|Geolocated images in Wikimedia Commons 2015-01-07
File:Commons geocoding.svg|Geocoded images on Commons, March 2007 - mid 2015
</gallery>

<small>(See [[File_talk:Commons_geocoding_graph.svg]] for numbers)</small>

== Use of the information ==
Clicking on the coordinates on an image page will lead to a list of various services that can show the location. It is also possible to browse Commons images on a map: 
* Geocoded images from Commons plotted in OSM per [https://tools.wmflabs.org/wikimap/?wp=false WikiMap tool] (lat/lon/zoom parameters or [https://tools.wmflabs.org/wikimap/?cat=Skyglow_in_New_York_City whole cat] possible).
* A mini world map with thumbnails of geocoded images can be found from [[tswiki:WikiMiniAtlas|WikiMiniAtlas on Commons]].
* Some geocoded images from Commons plotted in [https://tools.wmflabs.org/wiwosm/osm-on-ol/commons-on-osm.php?zoom=1&lat=0&lon=0 Open Street Map] (images tagged with {{t|object location}} are not displayed).
* <s>Some geocoded images from Commons plotted in [https://maps.google.com/maps?q=http:%2F%2Ftoolserver.org%2F~para%2FGeoCommons%2FGeoCommons-simple.kml&ie=UTF8&om=1&ll=35.46067,15.46875&spn=90.926037,111.445313&z=3 Google Maps] (images tagged with {{t|object location}} are not displayed).</s> – this service is no longer available
* KML-file of some geocoded images from Commons for use in Google Earth: [https://tools.wmflabs.org/geocommons/ GeoCommons] (images tagged with {{t|object location}} are not displayed).
* In the "gadget" tab of [[Special:Preferences]], there is an option "View category on Google maps". If enabled, this adds a link "map" to all categories. This shows the location of geocoded images in the category on Google maps.
* Adding {{tl|Geogroup}} to a category page adds links to view the images in the category with various maps.

Warnings: 
* Services displaying the tagged images (categories, articles etc.) in the map have frequent link failures.  Try to click a little later. 
* Indexing of the database is often delayed. A new image can appear in the map almost immediately, or after several days or even several weeks or months.
* The number of image-icons displayed in the linked maps is very limited, i.e. the map can display only some of the geocoded images from the displayed area. To display more images of a specific place, you can zoom in or shift to a less crowded area.
* At OpenStreetmap, icons with identical or nearby coordinates cover one another; only the top one is available to be clicked. 


Tools providing map outputs: 
* [https://tools.wmflabs.org/geocommons/ Geocommons] – creates KML of location templates on Wikimedia Commons, managed by [[user:Para|Para]]
* [https://wiki.openstreetmap.org/wiki/WIWOSM WIWOSM] – displays geometric objects from OpenStreetMap for Wikipedia/Commons articles, managed by [[User:Simon04|Simon04]], [[User:Retsam|Retsam]], [[user:Kolossos|Kolossos]]

==Things to do==
* Add geocoding to any location related media on Commons. Areas you know personally are easiest, but geocoding images from other areas based on satellite data and other photos is also possible. For help in finding material to work on, choose an interesting category and enter the name in [[tools:~para/GeoCommons/geocodingtodo.php|this tool]] to see a gallery of images that need to be geocoded.
* Find coordinates for pictures tagged with {{tl|location possible}} in: [[:Category:Location possible]]. 
* Refine inaccurate geocoding on images that are off the correct camera location, or have been positioned in the exact same place as a number of other images (see [[tools:~para/GeoCommons/inaccurates.php|<s>list</s>]])
* Monitor and fix tags of images with incorrect geocoding in [[:Category:Media with erroneous locations]] and recently geocoded images ([[tools:~para/GeoCommons/recentchanges.php|gallery]]).
* Find coordinates with unknown headings and try to fix them (see [http://toolserver.org/~dispenser/cgi-bin/geosearch.py?page=heading:\?&site=commons list]).
* Verify or fix coordinates of images imported from external sources where geocoding may be less conscientious (see for example [http://toolserver.org/~dispenser/cgi-bin/geosearch.py?regexp=source%3A%5BFf%5Dlickr&type=regex&site=commons Flickr images])
* Add camera heading for the images which contain coordinates without it.

==Participants==
<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
*[[User:Giovanni Ussi|Giovanni Ussi]]
*[[User:Gmaxwell|Gmaxwell]]
*[[User:evrik|evrik]]
*[[User:Dschwen|Dschwen]] 
*[[User:Kolossos|Kolossos]]
*[[User:Arcy|Arcy]]
*[[User:Para|para]]
*[[User:Wsiegmund|Wsiegmund]]
*[[User:EugeneZelenko|EugeneZelenko]]
*[[User:VanHelsing.16|VanHelsing.16]]
*[[User:Qyd|Qyd]]
*[[User:Bdesham|bdesham]]
*[[User:Simonizer|Simonizer]]
*[[User:Digon3|Digon3]]
*[[User:Jarekt|Jarekt]]
*[[User:MichaelBueker|Michael Büker]]
*[[User:Aldaron|Aldaron]]
*[[User:Michiel1972|Michiel1972]]
*[[User:Kimzoe200|Kimzoe200]]
*[[User:Padraic|Padraic]]
*[[User:Sten|Sten]]
*[[User:Moxfyre|Moxfyre]]
*[[User:Huwmanbeing|Huwmanbeing]]
*[[User:Twice25|Twice25]]
*[[User:AB|AB]]
*[[User:Imcall|Imcall]]
*[[User:Aviceda|Aviceda]]
*[[User:DirkvdM|DirkvdM]]
*[[User:ClemRutter|ClemRutter]]
*[[User:Helentr|Helentr]]
*[[User:Liamgabby66|Liamgabby66]]
*[[User:Diliff|Diliff]]
*[[User:Korax1214|Korax1214]]
*[[User:Richard001|Richard001]] ([[User talk:Richard001|talk]])
*[[User:Rodhullandemu|Rodhullandemu]] ([[User talk:Rodhullandemu|talk]])
*[[User:Nichalp|Nichalp]] ([[w:Q code|QTH]] = 18.56 N, 72.82 E, 12 m)
*[[:fr: user: Jean-Louis Hens]]
*[[User:Specious|Specious]]
*[[User:Giorgiomonteforti|Giorgiomonteforti]]
*{{u|Slaunger}}
*[[User:CT Cooper|CT Cooper]]
*[[User:PhilipMay|PhilipMay]]
*[[User:KenWalker|KenWalker]]
*[[User:Jim.henderson|Jim.henderson]]
*[[User:Jeriby|Jeriby]]
*[[User:Gapo|Gapo]]
*[[User:Igor22121976|Igors Jefimovs]]
*{{u|Senator2029}}
*[[User:Smoth_007|Smoth 007]]
*{{u|Enock4seth}}
*[[User:Emw|Emw]]
* {{u|epolk}}
*[[User:be..anyone|be..anyone]] 
*[[User:Kelly|Kelly]]
*[[User:Almondega|Almondega]]
*[[User:Jasonanaggie|Jason]]
*[[User:Aabdullayev851|Aabdullayev851]]
*[[User:Siddikbabu|Siddikbabu]] 
* [[User:Goutam1962|Goutam1962]] ([[User talk:Goutam1962|<span class="signature-talk">{{int:Talkpagelinktext}}</span>]]) 16:59, 16 April 2017 (UTC)
*[[User:Iketsi|Iketsi]]
*[[User:Augusthorsesdroppings10|Augusthorsesdroppings10]]

</div>

==See also==
*<span class="plainlinks">[{{fullurl:Commons:Geocode_Users|withJS=MediaWiki:Geocode_Users.js}} Geocode Users]</span> with [[MediaWiki:Geocode Users.js]] 
*[[Commons:Geocoding/Panorama]] Project to overlay Wikipedia-POIs over a panorama photo.
*[[/Overlay]] sub-project for creating KML map overlays on Commons. 
*[[MediaWiki:Exif-coordinate-format]] controls the formatting for GPS information embedded in the EXIF metadata of images; [[MediaWiki:Exif-coordinate-format/qqq|further info]].

[[Category:Commons geocoding|!]]