We're all pilgrims on the same journeybut some pilgrims have better road maps.
Hotspur, in Shakespeare's Henry IV Part I, III:1
A plague upon it! I have forgot the map.
It may be a small world, but the Web is a big scary place. Search-engine providers are looking for new ways to provide "relevant" content; weblog writers are looking for new ways to connect with audiences "near" to them.
"Mapping (on) the Web" illustrates simple techniques for spatializing web content and producing interesting geographic visualizations of web-found things, making the most of existing web mapping services.
Commercial web mapping services, while being careful to exercise their perceived intellectual property rights, gain a lot from allowing people to annotate their maps; a model of user-contributed, "added-value content" that has worked out so well for Amazon.com.
Meanwhile, web toolkits made by enthusiastic amateurs, like WorldKit and GPSVisualizer, allow you to make your own maps via the Web. Geourl, a successful early system for adding geotags to web pages, has been succeeded by different schemes for annotating weblog feedsin any of several flavors of the RSS (Really Simple Syndication or Rich Site Summary) format.
Once your web pages or weblog entries are annotated with geotags, not only can you make interesting visualizations of them, but anyone with the desire and a big enough set of hard drives can crawl the Web and make spatial indexes of what's where. Tagging content with latitiude and longitude is just one option for geo-annotating the Web; Chapter 7 illustrates many things you can do with "best-fit" locations for place names.
Geolocating web content is an especially interesting prospect for search engines, which will be able to provide targeted directory services to the next generation of web-capable mobile devices. The "global village" vision offered by Internet pioneers starts to look like a set of interconnected, tiny hamlets; a Web that looks more like the world looks.
Some mobile telecom companies want to provide "walled gardens," leading the user by the nose through a set of carefully vetted, sponsored Points of Interest. Spatial web search could also lead to balkanization of the Web into islands. MSN's new web search, in beta as of writing, provides a "Find Near Me" option that is only available to users connecting to their site via an Internet address in the United States. Non-U.S. users can't look at or experiment with, the spatial search options. This technique, known as IP geolocation, can roughly approximate the location of a user in a country, because "blocks" of addresses are loosely allocated on a country-by-country basis. IP geolocation was notoriously used to stop non-U.S. users from accessing http://www.georgewbush.com/ in the run-up to the 2004 presidential elections.
Yoking what you can see on the Web to where you're looking at it from leads to no two people ever having quite the same view of the Internet. Perhaps this helps reflect reality; no two people ever have the same worldview. Geo-annotations, along with collaborative recommendation systems, allow people or groups of people to create their own filtered spatial experiences: all the coffee shops and bookshops in London that an anarchist might visit, or the places that might interest a stockbroker. It's important to be able to share worldviews, and try out different people's filters for a day, to have the choice to explore Seattle using maps of Utrecht or visit a virtual Bangalore from your living room in Riga.
We hope this chapter illustrates how, with simple techniques that don't require a massive re-engineering of a geospatial web, you can build interesting sites that will plug into a future world of "locative services," yet still be interesting on today's desktop.