geo (pronounced "gee-oh") is a simple format for marking up WGS84 geographic coordinates (latitude; longitude), suitable for embedding in (X)HTML, Atom, RSS, and arbitrary XML. geo is a 1:1 representation of the "geo" property in the vCard standard (RFC2426) in XHTML, one of several open microformat standards.
- 1 geo
- 1.1 Draft Specification
- 1.2 Introduction and Background
- 1.3 Semantic XHTML Design Principles
- 1.4 Format
- 1.5 Examples
- 1.6 Examples in the wild
- 1.7 Implementations
- 1.8 References
- 1.9 Work in progress
- 1.10 Related Work
- 1.11 Similar Work
- 1.12 See Also
- 1.13 Related Pages
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Inspiration and Acknowledgments
Thanks to everyone who participated in the Geo Microformat BOF at O'Reilly's Where 2.0 conference, and in particular to Nat Torkington and Vee McMillen of O'Reilly for arranging and hosting the BOF. Thanks to Chris Hibbbert for providing the real world geo-caching example.
Introduction and Background
At the Where 2.0 conference in June 2005, there was widespread recognition that the community needed a way to simply and easily publish visible, extractable, geographic location information on the Web, given how often bloggers, and numerous other sites publish such information. The geo microformat BOF discussed this very topic, and concluded with a consensus decision to just try using geo from vCard/hCard.
This specification introduces the geo microformat, which is a 1:1 representation of the aforementioned geo property from the vCard standard, by simply reusing the geo property and sub-properties as-is from the hCard microformat.
Publishers can both embed geo addresses directly in their web pages and feeds, as well as markup existing latitude/longitude coordinates in the context of the rest of the information in their web pages and feeds.
If the publisher knows and is publishing the name of the location in addition to its geo lat/long, then the publisher MUST use hCard instead of just geo to publish the name and geo lat/long of the location.
If the publisher knows and is publishing the address of the location, OR if the address of the location was what was actually entered by a human, and the publisher simply turned that into lat/long using some sort of a service, then the publisher SHOULD use adr to publish the actual human entered address information since that communicates far more semantic information than a simple geo lat/long coordinate.
Semantic XHTML Design Principles
Note: the Semantic XHTML Design Principles were written primarily within the context of developing hCard and hCalendar, thus it may be easier to understand these principles in the context of the hCard design methodology (i.e. read that first). Tantek
XHTML is built on XML, and thus XHTML based formats can be used not only for convenient display presentation, but also for general purpose data exchange. In many ways, XHTML based formats exemplify the best of both HTML and XML worlds. However, when building XHTML based formats, it helps to have a guiding set of principles.
- Reuse the schema (names, objects, properties, values, types, hierarchies, constraints) as much as possible from pre-existing, established, well-supported standards by reference. Avoid restating constraints expressed in the source standard. Informative mentions are ok.
- For types with multiple components, use nested elements with class names equivalent to the names of the components.
- Plural components are made singular, and thus multiple nested elements are used to represent multiple text values that are comma-delimited.
- Use the most accurately precise semantic XHTML building block for each object etc.
- Otherwise use a generic structural element (e.g.
<div>), or the appropriate contextual element (e.g. an
- Use class names based on names from the original schema, unless the semantic XHTML building block precisely represents that part of the original schema. If names in the source schema are case-insensitive, then use an all lowercase equivalent. Components names implicit in prose (rather than explicit in the defined schema) should also use lowercase equivalents for ease of use. Spaces in component names become dash '-' characters.
- Finally, if the format of the data according to the original schema is too long and/or not human-friendly, use
<abbr>instead of a generic structural element, and place the literal data into the 'title' attribute (where abbr expansions go), and the more brief and human readable equivalent into the element itself. Further informative explanation of this use of
<abbr>: Human vs. ISO8601 dates problem solved
Note that all the properties in geo are singular properties, and thus the first descendant element with that class should take effect, any others being ignored.
Human vs. Machine readable
<abbr> element is used for a property, then the
title attribute of the
<abbr> element is the value of the property, instead of the contents of the element, which instead provide a human presentable version of the value.
Sometimes only part of an element which is the equivalent for a property should be used for the value of the property. For this purpose, the special class name
value is used to excerpt out the subset of the element that is the value of the property. See hCard for details on this.
Root Class Name
The root class name for an geo location is
This is the list of properties in geo, taken from hCard:
See hCard parsing, with the only difference being that "geo" is the root class name, rather than "vcard".
This section is informative.
Example from RFC2426
Section 3.4.2 of RFC2426 has a simple geo example:
this vCard fragment as a geo, as first documented on the hCard examples page:
<div class="geo">GEO: <span class="latitude">37.386013</span>, <span class="longitude">-122.082932</span> </div>
this geo could be displayed as:
Note that this is a live geo microformat, which will be found on this page by parsers.
Real world geo example
Here is a sample of published lat/long info (from geocaching: Noble Steed):
N 37° 24.491 W 122° 08.313
With geo markup:
<div class="geo"> <abbr class="latitude" title="37.408183">N 37° 24.491</abbr> <abbr class="longitude" title="-122.13855">W 122° 08.313</abbr> </div>
This geo might be displayed as:
Again, this is a live example.
Note that since the real world example used a more human readable presentation of the geo coordinates, we use the abbr design pattern to keep that more human readable presentation, and in addition provide the respective absolute numerical values for the geo.
Examples in the wild
This section is informative.
The following sites have published geos, outside their normal context of hCards, and thus are a great place to start for anyone looking for examples "in the wild" to try parsing, indexing, organizing etc., in addition to those in many hCard examples in the wild. If you find geos outside of hCards anywhere else, feel free to add them to the top of this list. Once the list grows too big, we'll make a separate wiki page.
Pages with live Geo can use this button (see buttons#Geo for any recent additions):
- Christian Hess uses Geo to indicate where pictures in his photo gallery where taken, such as here and here.
- Txioka has support for geo and hcalendar microformats, parses twitter messages with twitter-nanoformats and converts to geo and hcalendar.
- NaviTraveler, e. g. Lincoln Memorial.
- Response in under 12 hours, to advocacy request - Andy Mabbett
- Caving in the Settle Area uses Geo to mark up the U.K. NGR for cave locations.
- Great Circle Mapper ("GCM"; e.g. sample GCM trip, BHX on GCM)
- Creation design & marketing has Geo microformat on the contact information.
- Wikipedia now has a template, hcard-geo, for in-line hCards with coordinates, using Geo, such as that on Engine Arm
- LogOn.ie have added geotags (and hcard) to their contact page.
- www.davidosbornephotography.co.uk has implemented Geo on all location photography pages; eg. Callanish Stones
- Wikipedia-EN templates_generating_Geo
- Wikipedia-IT now has Geo on all pages using the coord template, e.g. Messina. Andy Mabbett 07:05, 26 May 2007 (PDT)
- 'Area' pages on Wholemap, summarizing the photos, videos, etc... for a specific area, now have Geo codes - Niagara Falls, for example May 10, 2007
- The Italian Wikipedia, for example Genova (Genoa)
- I've just added geo support to all of Socialight's Sticky Notes - here's an example - http://socialight.com/note/2007/4/14/11Aqk_a-great-way-to-spend-a-few-hours
- The Bay of Islands site has geo on its main page, and all photo pages. Example: photo of Edgewater Apartments
- I've added geo to all images tagged in Wikimedia Commons using decimal values. Example: Montreal City Hall, Jan 2006 Andy Mabbett 08:54, 12 Apr 2007 (PDT)
- Now on pages tagged in D-M-S also.
- Spotstor.com - e.g.  uses Geo for all coordinates displayed on the site.
- Panoramio - e.g. 
- Wikipedia-NL now has Geo on all its map-links pages, e.g. maps for Wikipedia-NL article on Birmingham
- Called from 87,724 article pages as of 2006-04-09; reportedly the sixth most popular website in the Netherlands .
- I recently added Geo to Wikipedia-DE's map link pages e.g. maps for Wikipedia-DE article on Birmingham. Andy Mabbett 14:27, 9 Apr 2007 (PDT)
- I've just added "geo" to OpenStreetMap documentation pages - see Birmingham page on OpenStreetMap for example. Andy Mabbett 02:39, 6 Apr 2007 (PDT)
- I've just added Geo to Wikipedia's GeoTemplate which is called by many thousands of other Wikipedia pages. Example: the coordinates (top right) in  link to ; the latter now has a Geo microformat. Andy Mabbett 03:38, 30 Mar 2007 (PDT)
- jillesvangurp.com provides an xsl stylesheet to transform Google Earth place-marks (kmz files) into html with nested lists of geo formatted places. Several examples are provided.
- Geograph British Isles has experimental support for geos on 350,000+ photo pages, for example http://www.geograph.org.uk/photo/1234
- POI66 has over 58,500 waypoints geo-formatted, many describing trails e.g Mijn pelgrimstocht naar Santiago
- 3AM Productions has published coordinates of cities both in and outside the context of hCards under Jason's and Gil's pages.
- Dan Connoly's Index of Events has a few geos
- Notes that two of the geos are considered invalid because they use commas instead of semicolons
- Wikitravel now has the facility to add co-ordinates for the subject of the article, and publishes them as a 'geo' microformat - e.g. Wikitravel - Birmingham; see The announcement.
- Flickr now supports the geo microformat on all geotagged photos. Within 11 days of launch there are now over 3,000,000+ photos (as of 2006-09-07) marked up with the "geo" microformat.
- ocono.com has marked each of it's "Upcoming Events" items with lat/long values.
- Harry Chen has marked up his geo location
- Multimap.com uses the geo microformat to mark up latitude and longitude values on map pages.
- Pete Prodoehl geotags posts on his blog.
- 07.pagesd.info uses the geo microformat to mark up latitude and longitude values for each commune of the Ardèche département in France.
- OpenGuides has support for the geo microformat in svn, and for now you can see it in action on the Cotswolds OpenGuide
Examples with some problems
Entries may be moved here if there's a problem with the way Geo is used on the page concerned. If the page is yours, and you want to improve it, see the hCard & Geo FAQ, or raise any queries on hCard & Geo Issues or the mailing list, where people will be happy to help you.
This section is informative.
The following implementations have been developed which either generate or parse geos outside the context of hCards. If you have an geo implementation, feel free to add it to the top of this list. Once the list grows too big, we'll make a separate wiki page.
- I've added Geo mark-up to the output of Wikipedia's GeoTemplate which is called by many thousands of other Wikipedia pages. Example: the coordinates (top right) in  link to ; the latter now has Geo mark-up in the "Mark-up" section. Andy Mabbett 03:10, 13 Jul 2007 (PDT)
- GIS-Wiki's "hjl_getCoor" now outputs Geo markup, from a Google Maps API.
- AddressFix takes any valid address in the listed countries (as at 2003-07) or map point (using GoogleMaps API) and outputs geo markup.
- Countries: Andorra, Australia, Austria, Belgium, Canada, France, Germany, Gibraltar, Italy, Japan (but only in Japanese), Liechtenstein, Luxembourg, Monaco, Netherlands, New Zealand, San Marino, Spain, Sweden, Switzerland, United States of America and the Vatican City.
- For countries other than the UK, the British Isles and China it provides geocoding for country names and city names (e.g. "Nairobi, Kenya").
- For UK, the British Isles and China, Google returns an error.
- GreaseRoute is a GreaseMonkey user script (also available as a simple Firefox Extension) which will add icons for displaying the MapQuest map of a Geo. Written by Andrew Turner
- podster.de finds geo markups in podcast RSS Feeds and maps soundseeing episodes on a map (German only)
- Calvin Yu has written a web service that will allow you plot and describe places on a Yahoo Map easily using hReview and Geo.
- pnh_mf is a plugin for Textpattern that supports embedding geos and other microformats in templates and blog posts. Written by Chris Casciano.
- Brian Suda has written some geo extracting code to convert geo microformats to KML for use with Google Maps and Google Earth. There is also a bookmarklet to extract the data and pass it to google maps automatically. He is working on a GeoRSS version for Yahoo! Maps as well.
- GPX export is done, but needs some tweaking and testing. Just change &type=(kml|georss|gpx). Not quite ready for primetime yet. Feel free to test and send feedback.
- GeoPress is a WordPress (http://wordpress.org) plugin that supports embedding adrs, geo, maps (dynamically switchable between Google-Yahoo-Microsoft Maps), and GeoRSS (http://georss.org) feeds. Written by Andrew Turner
- vCard RFC2426 (HTML reformatted version of RFC2426)
- XHTML 1.0 SE
- TIGER Map Service
- Wikipedia article on GeoTagging
Work in progress
This specification is a work in progress. As additional aspects are discussed, understood, and written, they will be added.
- luna (proposal for geo-style microformat for co-ordinates on The Moon)
- mars (proposal for geo-style microformat for co-ordinates on the planet Mars)
- geo-extension-nonWGS84 - extends Geo to include the above, and for representing coordinates on other planets, moons etc.
- thoughts on addind time and reference system to the geo microformat, that could also be used for places on other celestial bodies
- Geo cheatsheet
- Geo examples
- geo formats - previous/other attempts at geo related formats
- Geo brainstorming - brainstorms and other explorations relating to Geo (and Geo in hCard).
- see also hCard brainstorming
- Geo advocacy - encourage others to use Geo.
- Geo examples in the wild
- Geo forms part of hCard 1.0, so please use:
- location-formats - research which led to the development of Geo.
- proposed extensions
- Geo profile - draft