Comparing the Cartography of Google Maps and Ask.com Maps

Dude, Where's my Freeway?

Go ahead, fire up Google Maps and type in Denver, CO.

Something that jumps right out is that you can't quickly find Interstate 25, the major north-south highway/freeway/expressway in Denver. You see this obviously major route, snaking along the S. Plate, curling around downtown... but it's labeled as US Route 87. It takes some inside knowledge to infer that this is I-25. This is a pretty bad cartographic blunder in my opinion.

So, what's the cause of this problem? Well, the data come from NAVTEQ and many road
segments have multiple names. In this case, some roads are both I-25 and US 87. My opinion is that it's the job of the cartographer or the person that builds the mapping app to label this road as I-25. I'm not saying its easy to do this, but it should be this way.

Ask.com doesn't make this particular mistake. They label the interstate as both I-25 and US 87. In my opinion, this is more correct.

Interesting side note:

I've also thought there was something 'kinda cool' about how freeways in some cities have names. You'll hear these names on local traffic reports, and you may even see green sign along the start of a freeway stretch. But, you usually don't see these names on maps. Perhaps I find this interesting because there's more history in a freeway name than a number. Some examples: 'The Santa Monica Freeway' and 'The Pomona Freeway' in Los Angeles, and the 'Keeler St. Expressway' in Rochester, NY. I also think that named freeways are a weapon for locals to keep newcomers at bay.

Enough Already

Something you notice when looking at the Google and Ask.com maps of Denver is a lot of unecessary label repetition. What I mean is that the I-70 highway shield might appear 3, 4, or 5 times in a given map view. US 6 is another example.

The cause of this... data. Both online map apps use NAVTEQ data, and for smaller scale maps (maps covering larger geographic areas) routes are comprised of many short line features. It looks to me like the NAVTEQ data are just getting thrown straight into some automated labeling software...

...in my opinion, too many are being labeled. What should be done is to label the minimum number of times necessary to make it clear which road is which. So, basically, for these main routes, labeling once between major intersections is what you shoot for.

This is another tough thing (really tough) to nail in an automated system. Sometimes you can help yourself by pre-processing your data, dissolving roads by route number for example, before sending data to your automated labeling processes.

So, we've learned today that high quality labeling can be very difficult in an automated mapping system.

In my next post, I'll continue this cartographic critique of Google Maps and Ask.com Maps...

Talk to you soon,

-Cory