There has recently been a lot of discussion around KML becoming part of the OGC and the future of GeoRSS and KML. Will GeoRSS use KML payloads, or vice versa? Will one just subsume the other? After speaking with a bunch of people at Where, and also thinking about various announcements and talks given by Google-ites, Geo-ers, and standards makers, I'm proposing the following practice for using GeoRSS and KML together along with other formats.
In the talk announcing KML submission to OGC, the phrase "KML is HTML for the geospatial web" was used. I think this is a perfectly apt analogy. To complete the analogy, (taking you back to your SAT days)
HTML : RSS :: KML : GeoRSS
The purpose of the following examples is to illustrate the use of GeoRSS to syndicate KML content, similar to RSS support in HTML. GeoRSS merely adds a geographic component to the common RSS that syndicates web content. KML similarly offers a geospatial alternative representation of HTML content.
Therefore, as appropriate, GeoRSS should be used based on existing usages of RSS. This means providing a rel="alternate" link in both HTML and KML files. Conversely, an Atom or RSS feed requires use of a 'link' element to reference the originating content of the syndication. A rel="alternate" can then be used in a GeoRSS feed to reference the KML version of that content.
Within a GeoRSS file, the entire feed, or channel, can link to the content in type="text/html" and type="application/vnd.google-earth.kml+xml". Within a single entry, the GeoRSS feed can then link to the specific anchor, or element, within the original HTML or KML content using an anchor in the href.
<entry> <title>This is my first articletitle> <linkhref="http://example.org/2007/06/04/article"/> <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6aid> <updated>2003-12-13T18:30:02Zupdated> <summary>
KML is the HTML of the geospatial web, used to visualize content, and GeoRSS is the syndication of that content.
While you're here, make sure to check out my <ahref="http://example.org/myspots.kml#favoritepark"type="application/vnd.google-earth.kml+xml kml">favorite parka>. summary> <linkrel="alternate"type="application/vnd.google-earth.kml+xml" href="http://example.org/kml_georss.kml#article1"/> entry> feed>
Within an HTML file, the element can contain alternate links to the KML representation as well as the GeoRSS syndication. Similarly, KML 2.2 can contain an
written on June 22, 2007
posted in GeoRSSNeogeographyKMLBack to Top
About the Author
Andrew Turner is an advocate of open standards and open data. He is actively involved in many organizations developing and supporting open standards, including OpenStreetMap, Open Geospatial Consortium, Open Web Foundation, OSGeo, and the World Wide Web Consortium. He co-founded CrisisCommons, a community of volunteers that, in coordination with government agencies and disaster response groups, build technology tools to help people in need during and after a crisis such as an earthquake, tsunami, tornado, hurricane, flood, or wildfire.