Geo is a microformat used for marking up WGS84 geographical coordinates (latitude;longitude) in (X)HTML. Although termed a "draft" specification, this is a formality, and the format is stable and in use; not least as a sub-set of the published hCalendar and hCard microformat specifications. Use of Geo allows parsing tools (for example other websites, or Firefox's Operator extension) to extract the locations, and display them using some other website or mapping tool, or to load them into a GPS device, index or aggregate them, or convert them into an alternative format. Version 3 of the Firefox browser is expected to include native support for microformats[1], including Geo.
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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.
(Note - MUST and SHOULD are used per the IETF document RFC 2119).
In Wikipedia, (point) geo microformat is used as part of {{}} which is the preferred way to add point location information to articles and paragraphs. There are two ways to convert ordinary (X)HTML into a geo microformat:
Three classes
Adding three classes. For example the marked-up text:
<div>Belvide: 52.686; -2.193</div>
becomes:
<div class="geo">Belvide: <span class="latitude">52.686</span>; <span class="longitude">-2.193</span></div>
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.
One class
In some cases, a shorthand version may be used, with just the outer class. Latitude MUST be first:
Belvide Reservoir is at 52.686; -2.193.
becomes:
Belvide Reservoir is at <span class="geo">52.686; -2.193</span>.
Note that the separator MUST be a semi-colon (;). If the display of some other separator is desired, then the abbr element can be used, with the value to be interpreted placed in its title attribute:
Belvide Reservoir is at <abbr class="geo" title="52.686;-2.193">52.686, -2.193</abbr>.
This can also be used to display the location using some other schema:
Belvide Reservoir is at <abbr class="geo" title="52.686;-2.193">Grid reference SJ870099</abbr>.
However, it is considered bad practice to use abbr to hide the location completely:
Belvide Reservoir is <abbr class="geo" title="52.686;-2.193">nice to visit</abbr>.
Accessibility concerns
Concerns have been expressed [2] that the use of the abbr element (using the so-called abbr-design-pattern) in the above manner causes accessibility problems, not least for users of screen readers and aural browsers. Work is underway to find an alternative method of presenting coordinates [3].
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 active proposals, none mutually-exclusive, to extend the geo microformat:
- geo-extension - for representing coordinates on other planets, moons etc., and with non-WSG84 schema
- geo-elevation - for representing altitude
- geo-waypoint - for representing routes and boundaries, using waypoints
Users
Organisations and other websites using Geo include:
- Flickr - on over 3 million photo pages
- Geograph British Isles - on 350,000+ photo pages
- Multimap - all map pages
- Photrax - all photo pages
- MyMap - example: [1] (Taiwanese language site)
- OpenStreetMap - wiki pages about places, GPS traces and diary entries
- The West Midland Bird Club
- Wikipedia - embedded in geo templates of map-link pages
- German Wikipedia - ditto
- Dutch Wikipedia - ditto
- Swedish Wikipedia - ditto
- Italian Wikipedia
- Wikitravel
Many of the organisations publishing hCard include a geo as part of that.
References
- See external links
- ^ Resig, John (2007-02-01). Microformats in Firefox 3. Retrieved on 2007-03-25.
- ^ Web Standards Project, hAccessibility: Abbreviations in Microformats
- ^ Microformats Wiki: Assistive Technology
External links
- Geo spec with notes and examples
- Geo cheat-sheet a quick reference
