geocoding

<img class="right" src="worldmap.jpg" />

Resolving an IP address to a hostname, or reverse
DNS, has been around for a while. However, resolving an IP address to a
_physical location_, or geocoding, has just recently come into its own.

If you're interested in the raw data, many of the regional
[RIRs](http://en.wikipedia.org/wiki/Regional_Internet_Registry) (notably
[RIPE](http://www.ripe.net/ripe/), [ARIN](http://arin.net/), and
[APNIC](http://apnic.net/)) publish dumps, or "splits," of their databases.
[This forum thread](http://forums.devarticles.com/t4529/s.html) has more
detailed information.

However, most people want something that they can simply plug into their web
site that will tell visitors where they're located. Companies such as
[Quova](http://quova.com/), [Akamai](http://akamai.com/), and
[MaxMind](http://www.maxmind.com/) provide IP-to-location services of varying
resolution and accuracy. Except for a few flukes (e.g. all AOL users are in
Virginia!), these services are fairly good.

Not surprisingly, they charge money for access to their databases. If you're a
business, I'll let you decide on that value proposition yourself. However, if
you're a small, independent web site, [GeoBytes](http://geobytes.com/) has a
free ([as in beer](http://c2.com/cgi/wiki?FreeAsInBeer)) mapping service you can
use. I'm using it on my [voyeurism page](/ryan.barrett.name/voyeurism.shtml)
right now. Just plug this javascript into your web site wherever you'd like to
show the user their location:

    <script type="text/javascript"
     src="http://map.geoup.com/geoup?template=CityName">

This results in a tiny script that prints the user's city, inline:

    document.write('Brooklyn')

I'm using it on my [voyeurism page](/ryan.barrett.name/voyeurism.shtml)
right now. If you'd prefer the user's region, country, or one of many pre-bulit
messages, you can take your pick from GeoByte's
[templates](http://geoup.com/GeoPhrase.htm#Templates).

One caveat: to support this service, GeoBytes occasionally
[shows an advertisement](http://geoup.com/GeoPhrase.htm#HowCanThisBeFree)
instead of your own page, about once every 50 page views. This is unfortunate,
so I'm looking for an ad-free replacement along the lines of
[InternetFrog](http://internetfrog.com/).