Geotagging Web Pages and RSS Feeds

Providing geographic metadata in Web sites and syndicated feeds can provide users with the ability to search easily for services and articles based on location and proximity.

My previous article discussed how geolocation by IP address enables applications and Web sites to determine users' locations automatically in order to provide specific location-based services to users and members of an on-line community. In this article, we present various methods by which Web sites can provide their geographic locations to static pages and syndicated feeds, in the form of meta information or geotags. Put another way, geolocation by IP address is the technique a Web site uses to determine where users are located; geotagging is the technique users employ to find out where a Web site is located.

Geotags typically locate the Web site's principle location on the Earth. This information can include latitude and longitude information for exact locations or simply city, region and country information for general locations. Web services, applications and users then can query this information to obtain directions (how to get from here to there), locality (what's near there) or context (where was this article written). Geotags differ from a simple address in that they usually are encoded in metadata and are not visible as part of the Web page. Furthermore, by following a standard, other services easily and reliably can find these geotags. Various semantic Web projects still are solidifying geospatial tagging standards, but several techniques already have become common and supported. This article presents these current techniques.

Why Geotag?

Providing a geographic location is beneficial particularly for retail and service businesses, tourist attractions and entertainment venues. Geographic link directories, such as A2B and Multimap, can index these services by location and allow users to search geographically as well as by service type. Currently, many of these services limit users in their selection of available services. But, it would be possible to allow for more complex queries, such as searching for "Italian restaurants within 2 miles of downtown Arlington, Virginia". Or, when using automatic geolocation, one could ask for "directions from my current location to the nearest theater".

Current location-based services rely on the Web site administrator registering with an on-line index and specifying its location. Some of these services charge a fee, and many are not used commonly, nor are they cross-referenced. Google is now beta-testing Google Local, a free engine that allows users to search for location-based services using complex queries such as the examples above. Unfortunately, Google Local probably uses a form of scraping instead of meta information, considering that the 2002 Google Programming Contest winner's entry, by Daniel Egnor, is a geographic search which: "includes a geocoder (... to turn street addresses into latitude/longitude coordinates), a simple indexer that looks for addresses and keywords in documents, and a query engine to search for documents matching certain keywords that also contain addresses within a certain distance of a target location". Still, Google Local is an excellent example of how providing geographic information on a Web site greatly can enhance its visibility and usefulness to potential customers and users.

Geographic metadata also is useful for bloggers and photographers. Traveling writers, travel writers and reviewers can give context to their articles by supplying specific geographic information about where they are writing from or where the business they are reviewing is located. Photographers can provide viewers with information necessary for better understanding the photograph by informing them of where it was taken. Environmental services are now beginning to offer syndication feeds for weather and earthquakes. By geotagging these feeds, aggregators could sort, search and display information by region and location. As a result, users would gain a better picture of the current events happening in their areas.

By embedding a geographic location in the metadata of the Web site, applications and Web-based services quickly and reliably can determine the site's location relative to search criteria. Using metadata prevents the confusion of an automated search bot having to determine the location from the site's text. The rest of this article discusses the techniques used for embedding geographic information in your Web site or syndicated feed.

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i have read several articles

nokia 5310's picture

i have read several articles on Geo tagging ,but this one i feel is the best in terms of content and illustrations i myself use to update about geotag or fear being tagged,but this is very detailed information.

Metadata are invisible: enter the Geotag Icon

Bruce McKenzie's picture

Wish I'd come across your summary of the situation earlier, although what is really interesting is how little has changed since 2005. Geotagging is about to surge forward for a number of reasons, but whether geo-location uses meta tags, microformats, or EXIF-GPS it's hard for people to identify content that is location-specific. All these standards are invisible to people (but not to machines). Visibility is one reason why we need a web "standard" geotag icon; others are that it provides visual homogeneity in meaning, is format- and service-agnostic, and encourages development of the semantic web.

This is the rationale behind the Geotag Icon Project, which is a community-designed icon free for use by geotaggers everywhere. See geotagicons.com.

Thanks

teia's picture

Thanks for the article. I wish there were a Drupal module that could do this automatically.

Drupal has great Geo-modules

Anonymous's picture

Drupal actually has great modules for adding GeoRSS and KML:

http://drupal.org/project/georss
http://drupal.org/project/kml

Great Article, got me started on geotagging

grasshoppermind's picture

Your article is an excellent reference for anyone wanting to geotag their own content. However, I also wanted to be able to tag any content. I finally figured out how to do this and I've written up a quick HOWTO: geotag anything article.
Many thanks

Superb Article

dankeblog's picture

I agree, the article is great, and I really hope it'll help me for my future website. Geotagging your content is one of the prospects.

Re:Geo

Falko Paradus's picture

The tools provided includes "WWMX Client Application", which it says will add geotagging to a photograph by dragging and dropping photos to a location on a map (presumably supplied as well).

For more accurate tags, it providess "WWMX Location Stamper", that checks a digital photo's embedded timestamp, correlates it to GPS track files loaded in GPX format, and "WWMX TrackDownload" that can be used to extract tracks from handheld Garmin GPS device (and some others).

Re: Geo

Florian Kater's picture

I don't know about software solutions, but there are a few cameras out
there with GPS built in that will give you that data, along with
direction you are facing and elevation. They are used in real estate,
appraising, etc. You then download from the camera to a map.

Geotagged blogs on Multimap

Richard Rutter's picture

Over the past few months, Multimap has been scraping weblogs for geotags. So far Multimap has collected and mapped nearly 6,000 blogs.

You can search for blogs on any given map by selecting 'Weblogs' from Multimap's local information feature. For example here is a map of blogs in Brighton, UK.

There are more details on Clagnut.

Man, don't you know today's

Diana's picture

Man, don't you know today's statistics? Very interesting to see it.
b.t.w geotap article is very useful.

Mobiletracker reports that

Faustus Erratus's picture

Mobiletracker reports that over the weekend, Yahoo released some
interesting alpha geotagging software called Zonetag.

It's the application for Nokia Series 60 smartphones that automatically
tags photos with the location where they were taken according to info
from the cellular towers the phone was connected to at the time. Photos
are then sent to Yahoo's photo sharing site, Flickr.

A2B - some extra features in last few days

Sam Critchley - A2B's picture

Hi Andrew (everyone),

Many thanks for writing the article - great article (which I will definitely be bookmarking) and it's very exciting for us at A2B to get a mention!

I think the real challenge for the future of the whole geotagging area is integration with mapping. Wealthy commercial applications can afford the huge prices for mapping data, but the USA is about the only country where full country mapping information is available for free (called "TIGER data" from the US Census), and commercial services are charging a LOT for mapping data (which A2B can't afford at the moment).

Anyway, thought you and your readers might like to know about a couple of new extras on A2B which add to what you wrote:

- RSS feeds. You can now autogenerate an RSS feed URL which shows "most recently added/updated sites within XX kilometres/miles" of your site.
- Blog/site buttons - you can now autogenerate the link for an "A2B Nearby" button for your blog/site which will show your visitors which other sites are geographically nearest to yours.
- Map-based A2B searching - you can now put up your own map image file (including scanned maps, assuming copyright permission) and generate imagemap HTML to put on your site.

Details in the latest A2B newsletter at http://forum.a2b.cc/viewtopic.php?t=26

Many thanks,

Sam

thanks!

Ben LeMasurier's picture

Thanks for the great article. I think I will start to include this in all the sites I build. Is there a known lat/long search engine?

thanks again,

Ben

uidzer0.org

geourl.org

neilp's picture

yea - you should check out geourl.org it (sort of) does lookups based on latitude and longitude.

re: Is there a known lat/long search engine?

Richard Rutter's picture

The map information are below every map on Multimap.com displays latitude and longitude. So you can search for any location world-wide and Multimap will give you the map and associated coordinates below.

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