My vehicle for learning about HTML5 geolocation was to write another Foursquare application. Since I don’t have a BB or iPhone or an Android phone, I use the Foursquare mobile website to do my check-ins. On that site, I have to do a search of venues to check-in to based on my “current” (i.e., last) city. That is fine if you’re always in the same city, but I bounce between Mississauga and Markham daily. Those cities aren’t even adjacent!

Occasionally, my search results aren’t even close to where I physically am. It would be great if the mobile website knew where I was when I visited the site, but it doesn’t do yet. I wonder how I could solve this problem? Oh right, by using HTML5 geolocation!

I put together a quick Foursquare check-in site called Foursquare Finder that does this. It only works if you have a HTML5 geolocation-capable browser, which is probably Firefox 3.5 (although Safari 5 and Google Chrome may work, but I never tried). Once you give it permission, it will retrieve your current location and then find the check-in venues nearby. You can also filter based on a search term.

The concept works quite well, but technically there seem be some challenges (out of my control). HTML5 geolocation seems to be a nascent technology and I get different results from different computers within the same LAN! I think it has to do with browser or OS version differences. On my netbook, I get an accuracy of ~40m, but my desktop reports an accuracy of 140000m!

And then, half the time, geolocation within the browser won’t work at all, so I use Google APIs as a fallback. For whatever reason, I can’t get the Google API to be accurate at all, it just seems to determine that you’re in a particular city. And not even the right one; when I’m in Markham it puts me in North York, and when I’m in Mississauga, it puts me in Etobicoke!

Posted by Kevin in Blogs Tags: 4sq, google, html5