There are web services that associate placenames with coordinates, like Tageo, GeoNames and Maplandia, and then make the placenames browsable by geographic criteria.

There are also web services that associate web URLs with coordinates, and then make these URLs browsable by geographic criteria: GeoURL was among the first, letting website authors add geotags to page headers, and then indexing these sites. A variation on this theme is the georeferencing of URLs created specifically for uploaded files of a certain type — Panoramio does this for photos, Freesound does it for recorded ambient sounds. Pin in the map, meanwhile, eschews findability for simplicity: Give it a coordinate pair, you get a URL back.

Tagzania is a more complicated beast. It lets you attach all sorts of metadata to a coordinate pair — tags, URLs (including of photos), a description — and this collection of associations is then too given a permalink URL. All tags and authors have their own KML and RSS feeds.

Now there is geotagthings.com. Where might it fit in? What’s so innovative about it?

For one thing, there is a change of emphasis vs. Tagzania. In Tagzania, you start with a location on the map, then attach a URL, if you like. In geotagthings, you start with the URL, then go to the map to georeference it. In this respect it is much like GeoURL, except that the work is done by users, rather than by authors. Geotagthings doesn’t do non-geospatial tags for URLs — del.icio.us already has that niche covered.

What’s innovative in geotagthings, however, is how it exploits the user-generated geotagging data: You can set up a feed that returns all most recent URLs georeferenced to within a specific geographic area — a circular catchment area with a user-set radius.

I’m looking forward to the day when newsfeed readers let me set up alerts for GeoRSS-enhanced content associated with specific geographic regions. Geotagthings.com, meanwhile, already offers the geographic equivalent to services I use today to find new stories for Ogle Earth: Just as I save searches for “KML”, “KMZ” and other terms in popular blog aggregators as news feeds, geotagthings.com lets me save searches for content associated with a specific region as a news feed. In my future newsfeed reader, geotagthings.com feeds will serve as a geographic safety net, just as my “KML” search term feeds ensure I don’t miss a relevant story if it isn’t covered by the blogs i follow.

This makes geotagthings.com an important new tool among the georeferencing services available online. But it’s still late-alpha-early-beta, so there is room for further polishing. Here are some suggestions from my own use:

• Yahoo! maps returns its map tiles too slowly, and in Europe the detail is very scarce compared to other ajax mapping services. Finding a place on the map takes too long.
• The feeds are still bit rough around the edges. I wish the feeds were clickable rather than just cut-and-pastable. In any case, Newsgator won’t accept them as they are, currently.
• How spam-resilient is geotagthings.com? GeoURL seems to have a lot of automatically generated content. I’m guessing geotagthings.com will be better insulated agains spam, as you need to register to contribute, and abusers would presumably have all their content removed along with their account, in one fell swoop.
• If geotagthings.com were to automaticaly use the information already found in GeoURL’s header geotags when adding a site via the bookmarklet, this would greatly speed up the process.
• Geotagthings.com’s feeds are created dynamically, from coordinate parameters in the feed’s URL. This means it would be trivial to return a KML file for a bounding box when updating a network link. This makes it possible to browse the geotagthings.com database by roaming Google Earth.

Overall, I think geotagthings,com can become a very useful service, depending on how often users find the time to geotag URLs they come across on the web.

(Via VerySpatial, GeoLibro and Slashgeo)