Geo (microformat)

Image:GeoGreatBarr.png|thumb|upright=1.5|A Geo microformat, detected on the Wikipedia page for Great Barr, by Firefox's Operator extension. Users may add alternative mapping sources to those shown, which are included by default.
Geo is a microformat used for marking up geographical coordinates in HTML. Coordinates are expected in angular units of degrees and geodetic datum WGS84. Although termed a "draft" specification, the format is a de facto standard, stable and in widespread use; not least as a sub-set of the published hCalendar and hCard microformat specifications, neither of which is still a draft.
Use of Geo allows parsing tools to extract the locations, and display them using some other website or web mapping tool, or to load them into a GPS device, index or aggregate them, or convert them into an alternative format.

Usage

If latitude is present, so must be longitude, and vice versa.
The same number of decimal places should be used in each value, including trailing zeroes.

The Geo microformat is applied using three HTML classes. For example, the marked-up text:

Belvide: 52.686; -2.193

becomes:

Belvide: 52.686; -2.193

by adding the class-attribute values "geo", "latitude" and "longitude".
This will display

Belvide: 52.686; -2.193

and a geo microformat for that location, Belvide Reservoir, which will be detected, on this page, by microformat parsing tools.

hCard

Each Geo microformat may be wrapped in an hCard microformat, allowing for the inclusion of personal, organisational or venue names, postal addresses, telephone contacts, URLs, pictures, etc.

Extensions

There are three proposals, none mutually-exclusive, to extend the geo microformat:

geo-extension - for representing coordinates on other planets, moons etc., and with non-WGS84 schema
geo-elevation - for representing altitude
geo-waypoint - for representing routes and boundaries, using waypoints

Users

Organisations and websites using Geo include:

Flickr - on over three million photo pages
Geograph - on over one million photo pages
Google
Multimap - all map pages
OpenStreetMap - wiki pages about places, GPS traces and diary entries
Wikipedia - embedded in geo templates of map-link pages
*German Wikipedia - ditto
*Dutch Wikipedia - ditto
*Swedish Wikipedia - ditto
*Italian Wikipedia
Wikivoyage

Multiple organisations publishing hCard include a geo as part of that.

h-geo

An alternative to Geo, h-geo, has been proposed. This is applied using three HTML classes. For example:

Belvide: 52.686; -2.193; 120

by adding the class-attribute values "h-geo", "p-latitude", "p-longitude", and "p-altitude".