Don't blame the online mappers
If your directions lead you astray, don't pin it on the guys in the van who are trying to keep you on track. Photos: Cartography in the Internet era
Or so they say. On a recent sunny Thursday morning, I went directly to the source to find out why online maps more than occasionally have bizarro directions that would make any good cabbie scoff.
Taking a leisurely drive around San Francisco's upscale Nob Hill neighborhood in a video camera-equipped van owned by Tele Atlas (one of the two main mapping data collectors), I realized that it's awfully hard to argue with video evidence. Tele Atlas has a van whirring with videos, computers and navigation equipment, capturing up-to-date navigation information about my city.
Seeing all this rather impressive equipment packed into a big white van, I had to wonder: What's the problem?
So I asked a Tele Atlas executive why online maps often have inaccurate information and offer driving directions that defy logic--for example, directing a driver to jump a street divider. In fairness, he had a pretty good explanation.
"It could be that the map is out of synch with reality," said Michael Mitsock, Tele Atlas chief marketing officer. "It's the ripple effect between when we gather the data" and when it is reflected on maps.
"We might change the database tonight, but it might take some time to ripple out to the consumer," he said. "Less often is it an error than a freshness issue."
Online mapping applications typically refresh the data under their maps every 90 days or so, according to Mitsock. So that would explain why, for example,
Tele Atlas updates its database every 24 hours and the changes are then pushed out to partners like Google, Yahoo, MSN and MapQuest for their online mapping applications, and to companies like Tom Tom, which makes car navigation systems and portable personal navigation devices. Navigation-enabled handheld devices and smart phones can cost anywhere from $500 to $1,000, Mitsock said.
Mapping applications often differ despite using the same underlying data from Tele Atlas because they make their own adjustments based on road construction or traffic patterns and use different algorithms, he said. Some will put you on the highway, some prefer surface roads.
Cruising in the gadget mobile
The Tele Atlas van, which was parked in front of the Ritz Carlton hotel on swank Nob Hill, drove a few miles with me as a guest. The van was certainly a sight to see. It had six video cameras mounted on top. Inside in the back were three custom-built computers with 3GHz IBM Pentium 4s; an Omnistar global positioning system unit; a heating unit for the video cameras, and an external hard drive for data backup.
A dynamic sensor by the rear driver's side wheel serves as a backup location determiner when the global positioning system signal wanes, as it does during tunnels.
A converter switches the van battery's 12 volts to the 110 volts needed to run the computer system and the UPS surge protection system.
In the rear seat is a Hewlett-Packard monitor that displays the shots the video cameras are getting. One worker drives the van and the other sits at the computer screen operating the computer that captures and displays the video.
The system captures frames every 8 meters and collects three to four frames every second. The video is updated in real-time, although there is a very slight lag, making for a slightly choppy video viewing experience.
Tele Atlas also gets information from 50,000 external sources, including satellite imagery, aerial photography, local planning boards and state transportation departments. It mashes all that information together, and feeds it into a database.
If there are discrepancies with the data Tele Atlas is fed-?and more than a few people, I imagine, would be uncomfortable getting directions from the local planning board--the company will send out the video camera van, or a different vehicle in which workers can verify data by sight and manually input into a laptop.
Tele Atlas has a few vans in most urban areas driving around pretty much all the time, said Mitsock.
On Friday, Tele Atlas announced that it is offering a new address database that will allow its customers to offer address-specific information on top of maps, instead of just street names. Tele Atlas also said it was offering the ability for merchants to put brand and category icons on maps.
So with all that said, take pity on the guys in the mapping van: They're doing their best to make sure you don't get lost.