[georss] Geolocation by reference

[Sean Gillies]

GeoRSS has literal locations well covered. A possible use case for
location by reference (hyperlink really) is coming up in my work and I
want to run it by this group.

My Pleiades project is collaborating with other digital classics
projects to build out an ancient history web. Pleiades aims to be the
authoritative gazetteer for the Greek and Roman civilizations; we
maintain place name and locations resources that can be linked to from
other projects for geographic context. For example, see this page on the
American Numismatic Society web site about a coin from the Xanthos mint:

http://publicserver.numismatics.org/collection/accnum/list?accnum=1977.158.477&single=1

The developers of the site are harvesting coordinates from the Pleiades
Xanthos record (http://pleiades.stoa.org/places/639166) and will be
turning them around for use in their own GeoRSS feed (of mints). It
works, but it's a fair amount of effort that has to be reimplemented
from site to site across our little history web.

I think there may be cause here to add more declarative syntax to the
georss:where element. My initial idea is that georss:where could have an
optional src attribute exactly as atom:content can. The value of the src
attribute should be the URI of a GML document. Like so:

  <atom:entry>
  ...
  <where src="http://example.com/locations/1.gml"/>
  </atom:entry>

where the resource at http://example.com/locations/1.gml would be

  ...
  <gml:Point>...</gml:Point>

In this way the numismatists can reuse the authoritative Pleiades
locations and need neither maintain their own duplicate database nor
continually synch against Pleiades resources. The synchronization could
become built in.

There is precedent in Atom for remote sourcing, but only to my knowledge
for atom:content. The src attribute feels pretty good to me, though I do
think that it has the potential to make location (which is metadata) a
bit too much of content (data). Does anybody have other ideas for
non-literal locations?

Sean