Wikipedia:Obtaining geographic coordinates
From Wikipedia, the free encyclopedia
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There are various ways to obtain geographic coordinates. Note that regardless of the source of coordinates, it is good practice to evaluate whether they appear reasonable at first glance.
[edit] Manually
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- Note: Printed maps will display coordinates plotted to the mapmakers chosen datum. in the UK who use OSGB36 , Ireland, France and German, these will not be the coordinates used in Wikipedia ( WGS84) leading to inaccuracies of over 100m. See Geographic coordinate system
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- Using a GPS receiver with a clear view of the sky.
[edit] On the web
There are services with searching or browsing abilities:
| Tool | Type | Description |
|---|---|---|
| http://www.geonames.org/ | Name search | Worldwide geocoding and reverse geocoding service : can search placenames, postal codes and show their coordinates. Also with generating of Wikipedia templates: place-search.php |
| GISWiki | Google Maps tool | The hjl_get_Coor tool has been developed, which takes the coordinates from a Google Map and builds the {{coor d|...}} or <geo>...</geo> markup.There is a version for the English and German Wikipedias available. |
| EarthTools | Global browser | Designed to give coordinates for places, sunrise and sunset times, local time zones elevation/height above sea level. It's extremely easy to use and has a very nice interface (takes Google Maps and adds more functions to it). |
| WWC link converter | URL coordinate converter | Allows you to paste in the URL from many popular online mapping tools and get the degrees minutes seconds, decimal degrees, and text for using the coordinates in Wikipedia. |
| MSN maps | Maps | Provides geographical coordinates of a location selected from their excellent maps (better than Multimap) if you know the trick. The trick is: First find the feature or the location you want to know the geographical coordinates of, either by manually using the map and zooming in or by entering it into the search field (first click on "Find a Place", then choose Place name in: World Atlas, then choose the right feature from the list). As soon as you approximately see the feature on the map, zoom in as far as possible or necessary. Then, left-click exactly into the center of the feature/area you want to know the geographical coordinate of. Then wait for a short while until the map is rebuilt. Then, right-click on the map wherever you want, choose "properties" and wait for a short while until a pop-up tab appears. In this pop-up tab, the geographical coordinates are already written (in degrees only). Then perform a "select all"-"copy". The degrees-only geographical coordinates can be directly entered into Wikipedia's {{coor d||N/S||E/W|}}-Template. In the preview, click on the template and you will get to the Map sources page. There, the degrees-only geographical coordinates are converted into degrees-minutes-seconds anyway and displayed automatically at the top of the page, so you can still decide if you want to convert the degrees-only-geographical coordinates into the degree-minutes-seconds-format (alternatively, you can also use the website http://id.mind.net/~zona/mmts/trigonometryRealms/degMinSec/degMinSec.htm for the conversion from degrees-only into degree-minutes-seconds). |
| Multimap | Global browser | Provides geographic coordinates of a location selected from a map. |
| Calculators | Conversion | Many scientific calculators (including the one that comes with Windows, use dms and inv dms) can convert coordinates. |
| The Getty Thesaurus of Geographic Names | Name search | Allows you to find coordinates with a place name search. |
| http://www.world-gazetteer.com | Name search | Provides geographic coordinates of many cities (select country - "cities" - city) |
| Geonet Names Server (GNS) | Name search | U.S. National Geospatial-Intelligence Agency (NGA) maintains a comprehensive database of non-U.S. place data. |
| The Libre Map Project | ||
| TerraServer-USA | Global browser | Zoom in on a location and get the values at left. |
| GISWiki | Google Maps tool | The hjl_get_Coor tool has been developed, which takes the coordinates from a Google Map and builds the {{coor d|...}} or <geo>...</geo> markup.There is a version for the English and German Wikipedias available. |
| GPSies.com | Google Maps tool | Gives coordinates for places, names, elevation/height above sea level on Google Maps (reverse geocoding). You can download the coordinate as GPX Waypoint, PCX5 Waypoint, LOC Geocache or Google Earth KML. |
| Great Circle Mapper | Name search | Has geographic coordinates for airports, heliports, and other facilities which have an IATA or ICAO code. You can also search by location name. |
Coordinates also can be found in other sources such as by:
- Looking at a website built by GPS users, e.g. http://geourl.org/ or http://www.findu.com/ or http://www.geocaching.com/
- Looking for GPS "Waypoint" files
- Looking at a wiki that uses map coordinates, e.g.http://susning.nu/
[edit] Google tools
- Google Maps can be used to find coordinates. Find the place you require coordinates for, and double click on it to centre the map around that point. Then click the "link to this page" link, and the coordinates (in degrees and parts of a degree in decimals) appear in the address bar, eg "http://maps.google.co.uk/?ll=51.455558,-2.605047&spn=0.032304,0.069523". In this case the latitude is 51.455558, and the longitude is -2.605047. The reverse is possible by entering the lat and long into the search bar, with a space between them. Based on Google Maps API and geocoder, this page simplifies the task by displaying directly the coordinates, including in one of Wikipedia formats (for English and French Wikipedias), and allowing quick finding of places either by moving the map or typing in postal addresses or place names. Informal research indicates that coordinates obtained in this way usually agree with precisely determined WGS84 coordinates to within about ten meters, or four decimal places in decimal degree notation.
- Copying the coordinates from the URL can be made easier with a Javascript-supporting browser, by adding the following bookmarklet (create a new bookmark with this code as the URL):
Centre the map on the point as previously, and then open the newly created bookmark. A coordinate template text will appear, ready to be pasted to Wikipedia.javascript:void(prompt('',"{{coord|" + gApplication.getMap().getCenter().lat() + "|" + gApplication.getMap().getCenter().lng() + "}}"));
- Googling for the city name together with "latitude", "longitude", which will give hits like http://www.infoplease.com/ipa/A0001769.html
- Google Earth makes it easy to search for the coordinates of any location and zooming in on them. There are many ways to obtain coordinates:
- Move the mouse cursor to where you want, and note the coordinates displayed in the lower left-hand corner of the earth display window. The display format can be changed in the Options. The numbers will have to be written from the screen manually, but this does let you choose an appropriately rounded value, without excess precision, for the location you're capturing.
- Google Earth 4.1 and newer can make a Google Maps URL, from which you can copy the latitude and longitude in decimal format as mentioned above. Just center the screen on your location by double-clicking on it, and then use the "View in Google Maps" button at the top.
- Create a placemark (probably in the "Temporary Places" folder). Right-click or control-click on the placemark; one of the options is "Copy". Copy the placemark and paste it back to a text editor. The result is a KML ("Keyhole Markup Language") description of the placemark, and since KML is XML, it's easily manipulable. Towards the bottom of the placemark is a tag
<coordinates>...</coordinates>which contains the long/lat coordinates in decimal degrees. Note that the order of the coordinates is reversed from the lat/long you were expecting; you have to swap them when you extract them. Also note that the precision is ridiculously high; you'll probably want to trim it down. - Install the Google Earth version of the hjl_get_Coor tool: Ald-Hjl-Koord-en.kmz. Once it's installed, a crosshair icon appears in the middle of the Google Earth screen. Move the view so that the crosshair is on your desired location, and then click on it. There is a link to the hjl_get_Coor tool, which gives the coordinates back in your chosen wiki markup that can be copied and pasted to an article.
- The Picasa application allows seamless integration with Google Earth to tag sets of images saved on the computer. Select the images to tag on Picasa, and then choose "Tools / Geotag / Geotag With Google Earth". Google Earth opens with first of the chosen images in the bottom right corner, and a crosshair in the middle of the screen. Move the view so that the crosshair is on top of the desired location, and click on the Geotag button. A placemark will be added to your Temporary Places folder, from where you can normally copy it in kml format as explained above. Clicking Done will return to Picasa, which can export the data in kmz at any later date.[1] [2]
- The exported kml or kmz file can also be converted to templates using the kmlconvert tool.
[edit] World Wind
- NASA World Wind can access a large online database of U.S. and global placenames (cities, villages and other geographic & anthropogenic features). Street addresses can be found using Yahoo and Virtual Earth geocoders (works for the US, Australia, UK, Japan... and maybe some other countries). (Offline search requires this pack http://www.worldwindcentral.com/wiki/Add-on:Classic_Placenames_cache_pack) Press Ctrl-F, enter the official place name, click Search, you will probably find the place you're looking for. Click Go. (of course you can navigate to the desired spot with your mouse; select View->Show Position to see the coordinates) Press Ctrl-C to copy the decimal coordinates. Paste it into Wikipedia. Example: For Tucson International Airport → worldwind://goto/world=Earth&lat=32.11611&lon=-110.94109&alt=24389"
[edit] Within Wikipedia
- Category:Lists of coordinates
- CatScan in the example with buildings in New York City with or without Coordinates.
[edit] Specific countries/places
- PlaceNames provides coordinates for locations and landmarks in the United States.
- For US coordinates, the USGS GNIS service is extremely extensive. It also provides linkouts to topozone and terraserver so that you can tweak the results to your liking.
- For US addresses, A2B provides you with the latitude and longitude of a US street address and returns nearest websites to that address. You can then add your own sites.
- For Australian placenames, try Geoscience Australia Place Name Search
- For placenames in Antarctica, try Geographic Names Information System, Antarctica
- For UK places Streetmap.co.uk is very useful for clicking on a precise point to show the coordinates. Near the foot of a page displaying a map is a link "Click here to convert/measure coordinates" which takes you to a "Grid Conversion Results" page with the WGS84 latitude and longitude amongst other useful values.
- UK places and Irish places traditionally use grid references, and a latitude /longitude system tied to a OSGB36 datum. This gives a 112m difference. OStoWiki Tool will translate data from Commons tags, or Grid References into wikipedia tags.
[edit] Public domain databases
The following U.S. government public domain geodata databases, as well as providing web lookups (see above) are also freely downloadable in their entirety in an easily-parsable machine-readable form:
- The United States Geological Survey's public domain GNIS database contains a huge list of locations in the United States. It can be found on the Web at http://geonames.usgs.gov/
- The U.S. National Geospatial-Intelligence Agency's public domain GEOnet Names Server contains a huge list of locations outside the United States. It can be found on the Web at http://earth-info.nga.mil/gns/html/
