Geocoding Examples

According to the World Wide Web Consortium (W3C), the basic geo vocabulary was created as "an informal collaboration" and is "not currently on the W3C recommendation track for standardization". Basically this just means that it is not standardized for professional GIS use, however, the Web community has adopted these tags and support is on the rise.

Basic example
Below is a barebones example of the geo elements. The longitude is represented by X, the latitude is represented by Y and the optional altitude value is represented by Z.

<geo:long>X</geo:long>
<geo:lat>Y</geo:lat>
<geo:alt>Z</geo:alt>


The prefix geo: is defined by the RDFIG Geo namespace at:
http://www.w3.org/2003/01/geo/wgs84_pos#

Namespaces are used in HTML and XML in order to expand the markup elements. The namespace listed above defines the various geo elements that can be used in your markup.

Geotagging a web page
In order to associate a location to an entire Web page, use the tag in the page's element:

<meta property="geo:lat">47.6087</meta>
<meta property="geo:long">-122.3406</meta>


Geotagging an HTML element
Addition to defining a Web page's geolocation, specific elements inside an HTML document can also contain geotags by using the tag in combination with the namespace declaration and a display:none style. Note that the namespace declaration is not needed if it has been defined in a parent element.

<span xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#" style="display:none">
<geo:lat>47.6087</geo:lat>
<geo:long>-122.3406</geo:long>
</span>


Geotagging an RSS feed
Your RSS feed actually supports two levels of geotagging. The overall feed can define the geo:lat and geo:long tags to specify a base location. In addition, each post can also contain the geo:lat and geo:long tags to define the location of particular blog item. The basic structure is the same as, but you must remember to declare the namespace. Here is an complete example displaying the use of the geo namespace and both types of geotagging (feed and individual post).

<"xml version="1.0" encoding="UTF-8">
<rss version="2.0" xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">
<channel>
<title>VlogMap.org</title>
<link>http://www.vlogmap.org/blog/</link>
<description>The World of Video Blogs</description>
<geo:lat>47.612</geo:lat>
<geo:long>-122.328</geo:long>
<item>
<title>The Mirror World</title>
<link>http://www.leanbackvids.com/videoblog/seattle/mirror-world/</link>
<geo:lat>47.5909</geo:lat>
<geo:long>-122.3309</geo:long>
</item>
</channel>
</rss>