Tuesday, October 13, 2009

More on the "Google data earthquake"

Following on from my previous post about Google shaking up the geospatial data industry, Steve Coast invited me and James Fee to join him for a discussion on the topic. James' blog post on the topic has 138 comments at the time of writing, which is a good indication of the interest in this change! You can listen to the podcast on the "Google data earthquake" here.

One topic I talk about in the call which I didn't cover in my previous post is where the Google street data comes from (they haven't said anything about this). To me it looks like a mixture of data they have captured from their StreetView cars, which seems to be good quality, and then probably TIGER data, which is much lower quality, where their cars haven't driven. Quite a few people have reported finding errors in street data that weren't there previously since the change. I found that Central City Parkway was missing from the map entirely, which is a pretty major highway that was completed in 2004. You can see this below, with OpenStreetMap on the left, and Google Maps on the right (screen shot using GeoFabrik's nice map compare tool):

Central City Parkway missing from Google Maps

I've reported the error to Google, so it will be interesting to see how quickly it gets fixed - and in general, how quickly they are able to fix up the apparently lower quality data in areas they haven't driven yet (though this assessment is not based on anything scientific).


Tom Churchill said...

They seem to be doing a pretty reasonable job: Your parkway is online now...

Peter Batty said...

Hey Tom, thanks for letting me know about this. I just looked a bit more closely and it's actually a strange semi-update - there's a geometry along the path of the road, but it's not named, has the wrong road classification and you can't route along it - more detail here.