Entering The Wonderful World of Geo Location

I thought I could not be out-geeked. With a background in radio, and having dabbled in the demo scene on the Commodore 64 and hung out on BBSes and IRC for a long time and all the other things normal kids don’t quite get, I thought I was safe in this area.
Then I went to my first WhereCamp, an unconference dealing with geographical issues and how they relate to the world of Web development. Even my A-Levels in Astronomy did not help me there. I was out-geeked by the people who drive and tweak the things that we now consider normal about geo-location on the Web.
Pulling out your phone, find your location and getting directions to the nearest bar is easy, but a lot of work has gone into making that possible. The good news is that because of that effort, mere geo-mortals like you and me can now create geographically aware products using a few lines of code. So, let’s give the geo-community a big hand.

Why Geo Matters

First of all, why is it important to consider physical location on this planet (at this moment) when we develop Web products? There are a few answers to this.
The first answer is mobility. The days of people sitting in front of desktop machines at home are over. Sales of mobile devices, laptops and netbooks have overtaken those of bulky stationary computers in the last few years. The power of processors now allows us to use smaller, more mobile hardware to perform the same tasks. So, if people use their hardware on the go, we should bring our systems to them. Which brings us to the second—very important—point: relevance.
Giving the user content that is relevant to the physical space they are in at the moment makes a lot of sense. We are creatures of habit. While we love the reach of the Internet, we also want to be able to find things in our local area easily: people to meet, cafes to frequent, interesting buildings and museums to learn about. The advertising industry—especially of the adult and dating variety—realized this years ago. I am sure you have come across one of the following before:

I am sure these ads are more successful than the ones that show only user names. That the photos and names are the same for every location doesn’t seem to be a problem (but yes, I noticed it). So how does it all work?

Getting The User’s Location Via IP

Every computer on a network has a number that identifies it: its IP address. The Internet is nothing but a massive network, and your IP number is assigned to you by the service provider that you have used to connect to that network. Because the numbers that service providers assign change from one geographical location to the next (much like telephone numbers), you can make quite a good estimate of where your visitors are from.
To find out where a certain phone number is from, you use a phone book. To find out where an IP is from, you can use the Maxmind GeoIP database. Maxmind also provides a JavaScript solution that you can use on websites:

This gives you some information on the user (try it out for yourself). The challenge, though, is relevance. Your IP location is the location of the IP that your provider has assigned to you. Depending on your provider, this could be quite a ways off (in my case, I live in London, but my provider used to show me as living in Rochester). Another problem is if you work for a company that uses a VPN. At Yahoo, for example, I have to connect to the VPN to read my company email, and I have to choose a location to connect to:

So, for a solution like the one highlighted above, I would show up as being in a totally different part of the world (which might be useful for watching Internet TV in the UK while I am in the US). IP geo-location, then, is an approximation, not a dead-on science.

Getting The User’s Location Via The W3C Geo API

Guessing geographical location via IP is possible, but it can also be pretty creepy. Being able to take advantage of your location is useful, but security-conscious users and people who are generally suspicious of the Internet are not happy with the idea of their movements being monitored by a computer. This makes sense: if I can monitor your whereabouts day and night, I would know where and when to rob your house without you being there.
There are a lot of solutions to the challenge of having good-quality geo-location and maintaining privacy. Google Gears has a geo-location service; Plazes helps you store your location; and Yahoo’s Fire Eagle is probably the most polished way to securely maintain your location on the Web.
The problem with all of these services is that they require the user to either install a plug-in or visit a Web service to update their location. This is not fun; browsers should do the work for you.
We now have a W3C recommendation for a geo-location API that allows browsers to request the geographical location of the user. This makes it less creepy, and you get real data back.
Firefox 3.5 and above supports the W3C geo-location API. So does Safari on the iPhone if you run OS 3.0 or above. If you use the API, the browser will ask the user whether they want to share their location with your website.

Once the user allows you to get their location, you get much more detailed latitude and longitude values. Using the API is very easy:

// if the browser supports the w3c geo api
if(navigator.geolocation){
  // get the current position
  navigator.geolocation.getCurrentPosition(

  // if this was successful, get the latitude and longitude
  function(position){
    var lat = position.coords.latitude;
    var lon = position.coords.longitude;
  },
  // if there was an error
  function(error){
    alert('ouch');
  });
}

Compare the IP and W3C solutions side by side. As you can see, there can be quite a difference in measuring the visitor’s location. The extent of the difference is shown in the following demo:

Converting Latitude And Longitude Back Into A Name

Having more information is nice, but we have lost the name of the city and all the other nice data that came with the Maxmind database. Because the location has changed, we cannot just grab that old data; we have to find a way to convert latitude and longitude coordinates into a name. This process is called “reverse geo-coding,” and several services on the Web allow you to do it. Probably the most well-known is the geo-names Web service, but it has a few issues. For starters, the results are very US-centric.
One freely available but lesser-known reverse geo-coder that works worldwide comes from a surprising source: Flickr. The flickr.places.findByLatLon service returns a location from a latitude and longitude coordinates. You can try it out in the app explorer, but by far the easiest way to use it is by using the Yahoo Query Language (or YQL). YQL deserves its own article, but let’s just say that, instead of having to authenticate with the Flickr API and read the docs, reverse geo-coding becomes as easy as this:

select * from flickr.places where lat=37.416115 and lon=-122.0245671

Using the YQL Web service, you can get the result back as XML or JSON. So, to use the service in JavaScript, all you need is the following:

Combine that with the other services, and we get a more detailed result and can put a name to the coordinates:

The Trouble With Latitude And Longitude

While latitude and longitude coordinates are a good way to describe a location on Earth, it is also ambiguous. The coordinates could represent either the centre of a city or a point of interest (such as a museum or a pub) in that spot.

WOEID to the Rescue

To work around the problem, Yahoo and Flickr (and soon will Twitter) support another way to pinpoint a location. The Where On Earth Identifier (or WOEID) is a more granular way to describe locations on Earth. Because Flickr supports it, we can easily get get photos from a particular area:

select * from flickr.photos.search where woe_id in (
  select place.woeid from flickr.places where lat=37.416115 and lon=-122.02456
)

Using this and a few lines of JavaScript, showing geo-located photos is pretty easy:

This has also been wrapped in a simple-to-use YQL solution. The following code will display 10 photos of Paris:

This makes it incredibly easy to give your visitors a sense of what part of the world a text is related to.

Adding Maps To Your Documents

Online maps have been around for a while now (and Google Maps was instrumental in the rise of AJAX), and many providers out there allow you to add maps to your documents. Google is probably the leader, but Yahoo also has maps, as does Microsoft and many more. There is even a fully open map service called Open Street Maps, which has been instrumental in the recent rescue efforts in Haiti.
If you want interactive maps, probably the easiest thing to use is Mapstraction, which is a JavaScript library that does away with the discrepancies between the various map providers and gives you a single interface for all of them. 24ways published a good introduction to it three years ago.
Probably the simplest way to show a map that supports markers and paths in your document without having to dive into JavaScript is the Google static maps API. It creates maps as images, and all you need to do is provide the map information in the src URI of the image. For example, in the script example above, this would be:

http://maps.google.com/maps/api/staticmap?
sensor=false
&size=200x200
&maptype=roadmap
&key=YOUR_MAP_KEY
&markers=color:blue|label:1|37.4447,-122.161
&markers=color:blue|label:2|37.3385,-121.886
&markers=color:blue|label:3|37.3716,-122.038
&markers=color:blue|label:4|37.7792,-122.42

You can define the size and type of the map. If all you provide is the location of markers, the API will automatically find the right zoom level and area to ensure that all markers are visible. Google’s website even offers a detailed tool to create static maps, including markers and paths.

Geo Is A Space To Watch

I hope this has given you some insight into all of the things you can do to bring the earth to your product and to put your product on the map. Geo-location and geo-aware services are already huge, and they’ll be even more important this year. There will be more services—some mobile providers are ready to roll out new hardware and software—and now you can be a part of it.
What the geo-world needs now is a designer’s eye, and this is where you can help the geo-geeks create apps that matter, that look great and that make a difference in our visitors’ lives. For inspiration, check out Mapumental, which allows you to pinpoint a place to live in London, or see how Google Earth and some 3-D Objects allow you to race a milk truck on real map data.