Wikipedia:Obtaining geographic coordinates
From Wikipedia, the free encyclopedia
There are various ways to obtain geographic coordinates. NB: regardless of the source of coordinates, it is good practice to evaluate whether they appear reasonable at first glance.
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[edit] Manually
- Looking at a printed map or atlas, either those you own or at a library
- Using a GPS satellite navigator
[edit] On the web
- EarthToolsis 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).
- MSN 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 page http://tools.wikimedia.de/~magnus/geo/geohack.php?params=... . 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 provides geographic coordinates of a location selected from a map, and many scientific calculators (including the one that comes with Windows, use dms and inv dms) will do these conversions as well.
- The Getty Thesaurus of Geographic Names allows you to find coordinates with a place name search.
- http://www.world-gazetteer.com provides geographic coordinates of many cities (select country - "cities" - city)
- The U.S. National Geospatial-Intelligence Agency (NGA) maintains a comprehensive database of non-U.S. place data, accessible via the Geonet Names Server (GNS).
- 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/
- Zooming in on the place on TerraServer-USA and getting the values at left
- On GISWiki 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.
[edit] Google
- 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.
- 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 zoom in on anything you want. Having done so, there are two ways to obtain coordinates. (1) Move the mouse cursor to where you want, and note the coordinates displayed in the lower left-hand corner of the earth display window. (You'll have to jot them on a scrap of paper and then type them back in. But this does let you choose an appropriately rounded value, without excess precision, for the location you're capturing.) (2) 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 in to the text editor or other text-handling utility of your choice. 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.
[edit] Within Wikipedia
[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.
[edit] Offline software
- NASA World Wind has a large database of U.S. and global placenames. Sorry, no street addresses. Press Ctrl-F, enter the official place name, click Search, you will probably find the place you're looking for. Click Go and 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"
