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Expectations of Auto GPS

May
29
2007

Recently I’ve had lots of conversations with GPS customers who have had varying expectations of auto GPS devices. Most people are shocked at what GPS devices have to offer, while a few other people might have set the bar too high. So here is what you should expect from your GPS device relative to mapping, routes, and points of interest (POI). But I want to start by sharing a little story which highlights some expectations of GPS and how quickly those expectations can change.

Story of Expecations

A couple of months ago I attended a trade-show with a few business partners. We were in a city that we had been in before, but an area where we didn’t know our way around like the back of our hand. The people I was traveling with and never really seen a GPS device in operation.

We were planning dinner one night and had decided on a restaurant across town. Despite knowing I had a GPS device with me, and knowing I operate this site, the people I was traveling with still wanted to consult both the restaurant and the hotel concierge for directions. I let them get the directions since it didn’t sound like they wanted to trust the GPS. A wise move, but unnecessary. I let them get the verbal directions.

So we set out on our way. They started navigating based on the directions they were trying to remember in their head while I plugged in the address on the GPS from the passenger’s seat and started watching the screen. Then they started to watch the GPS…

“You mean that thing even has all of the little streets on there too? It follows along where we are updating the picture? Hey, it speaks to you to remind you of the turn? Hey, look at that… It shows how long it is before the next turn and how long it will take to get there! And look, it even shows where the median starts!

They were certainly amazed. While not yet ready to trust the device, they were amazed at the technology. But within the next few minutes their enthusiasm was extinguished when they noticed that there was a newly constructed median that wasn’t yet in the GPS. They also pointed out that the GPS said “You have arrived” about 300 feet before it should have. And on the way home they were critical of the fact that the GPS didn’t have our condo in the database that had just opened a couple months before.

What I was most amazed about was how quickly their expectations of the device went from pure amazement of the moving map and being bewildered by the fact that the GPS has side streets to disappointment that not every POI was in the database and road changes just completed a few months before were not yet in the database.

With such a sharp turn of expectations of the device within one trip to a restaurant, there are certainly large gaps in expectations of GPS devices from people shopping for GPS devices. So here is what you should expect of your GPS device.

Mapping Quality

You will find maps that are not fresh enough to represent every aspect of the roads you are driving on today. Take a device as popular as the Garmin Nuvi and consider the maps that are shipping on it today. The most recent maps available are v8 in the USA which were released to Garmin from their mapping supplier, NAVTEQ, in April of 2007. So even with a brand new, top of the line GPS from Garmin the most recent maps available are over 1 year old. Lots can change in 1 year.

Another issue we hear frequently is “This GPS doesn’t even have my home address listed which has been there for five years!”. Yes, that is entirely possible, and it happens from time to time. It is unfortunate, but it does happen.

You can report errors you find in mapping back to the mapping companies. (NAVTEQ, Tele Atlas.) Keep in mind though that these companies work very hard to ensure the quality of their data. This means that they might not just take your word that something has changed and they will do what they can to verify through a second source that what you are telling them is correct. They also get tons of feedback from these systems and it can take time to verify your revisions. It isn’t uncommon for it to take several months for that to happen, followed by several months for your GPS company to get the new data, followed by time for them to process, format and release the data. The whole process going from your revision back to your GPS might be better measured in years than months.

Routing Quality

The second biggest piece of feedback I receive involves the routes picked by the GPS. “I can’t believe it sent me that way… that will take at least five minutes longer!”. In most GPS devices you can specify if you want the fastest or shortest route. But beyond that, devices can also try to do things to make your driving life easier. For when you drive on the right side of the road it is faster to make a right turn than a left turn because you don’t need to cross opposing traffic. Therefore a GPS might send you on a slightly longer route in favor of an additional right hand turn over a route that might otherwise be faster were it not for a left turn or two.

GPS devices typically create routes based on the relative speed limit of the road…. Not necessarily how fast people drive. There are two parallel streets near by home used to get to bigger highways. On one the speed limit is 30 and most people drive it at about 35. The other street has a speed limit of 55 and 45, however it is the end of a limited access highway and people typically drive it at 65. Most everyone will tell you that while the highway is further out of the way, it is the “faster” way to go. A GPS doesn’t that people drive 35 in the 30 zone and 65 in the 45 zone. Therefore while driving the posted speed limit the shorter, slower speed way will probably get you there faster but driving at the pace of many others on the road would suggest the other road is faster.

If you live in or near a bigger city, think of driving from one side of the city to the other side. What way would you take? If you put ten people in the room and ask them what is the fastest way to drive the same route do you think everyone would agree on the fastest way to get there? Most likely not. If you live in a rural area think of driving a longer distance to a nearby city. Does everyone agree your way is the fastest? Again, probably not. Therefore since humans can’t always agree on the best route, don’t expect your GPS to agree with you either.

POI Databases

This is an issue we’ve been seeing more recently. While the road database should be fairly complete and there is an attempt to map all public roads within the coverage area, GPS devices do not intend to include every POI in existence. In our specification database we list the number of POIs installed when this data is provided by the manufacturer. Simply put, if you purchase a GPS with 700,000 POIs installed, don’t expect it to have as many locations as a GPS which advertises 12,000,000 POIs.

There are some companies who offer multiple versions of the exact same model GPS with the only difference being price and the number of installed POIs. Just like not all businesses list themselves in the Yellow Pages, not all businesses will appear in POI databases. If POIs are important to you then really look at the number of installed POIs when purchasing a GPS.

Final Thoughts

Mapping, Routing, and POI databases have their limitations. I’m not saying these limitations are acceptable to the industry, however they do represent the current state of affairs. Have a healthy attitude towards your GPS. Remember your amazement the first time you saw a GPS in action and watched the moving map? Remember your excitement when you saw that it even has side streets? The next time you get road rage level anger at your GPS for sending you five minutes further “the long way” try to think back to how amazing these devices really are.

6 Responses


  1. Excellent explanation, Tim. I piggybacked on this on my blog today with some thoughts on what GPS actually does versus what people seem to think it does.

    It is a great challenge to the community (especially in the consumer products area where you focus (and I generally steer clear of) to manage the expectations of the user. Even the cheapest hand-held works a number of technological near-miracles per second but I guess the more miracles we get, the more we expect.

    Dave Starr — ROI Guy - May 29th, 2007
  2. To your list I would add the capability to catch a signal: how long does it take to get a fix once it is turned on, and also how it is affected by tall trees and buildings. My last GPS was a mess in a downtown area with high-rises, though it rated pretty well on the features you have mentioned above.

    Anthony Tauro - June 2nd, 2007
  3. I am really disapointed in the mapping of navteq and tele atlas. The sales person at the electronics store advise me against buying a GPS where I lice which is Saskatchewan Canada. I tried to enere my home address in the store unit and it couldn’t be found. This address has been here for atleast 10 years, so much for updating maps. I guess the mapping companies spend all their time in the BIG $$$ markets

    Don Hoornaert - June 9th, 2007
  4. seeking your advice on auto gps entry level, price range approx around 300.00 Canadian dollars

    William Ho - June 24th, 2007
  5. Since the gps knows speed and can/could drop bread crumbs, do you hear of any gps that “learns”? The technology could easily replace speeds on roads and allow the driver to add a road by driving it and then “name” it.

    Ned Webb - November 24th, 2007
  6. Ned – There are companies who monitor vehicles and provide speed estimates for any given day of the year and any hour. That data hasn’t made it into GPS devices quite yet, but should within the next year.

    As to learning new roads, there are too many parameters that the mapping companies track (over 200) marking everything from road surface type to lane with, elevation, rake, etc for a consumer GPS to replace the need for the mapping companies to map the road, however a tracklog could help them identify new places to map. In a way that is what TomTom’s MapShare system strives to do.

    Tim - November 24th, 2007



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