August 21, 2011

The need to have a plan B

NPR had a story about people who get lost, stranded, and even die in Death Valley because their GPS devices led them astray. After repeated instances like this, a Death Valley Ranger investigated and discovered that the devices were using old maps with roads that had long since disappeared. People following the GPS devices ended up on dirt roads that led nowhere.

I have written before at how surprised I am that people put their faith implicitly in technology. I find it incredible that anyone would even go to a place like Death Valley without at least some backup plan in case the GPS failed. Apart from errors, what would they do if the device started obviously malfunctioning or stopped working?

Just recently I had to go to someone's home. Their address was on Shaker Boulevard, which is a very long street with a wide grassy median with few crossover points, so I put their street number into Google Maps to get a rough idea of where the house was. I was surprised to find that the location given was two towns away from mine, since I was pretty sure that they lived in my own suburb. So I tried MapQuest and sure enough, it was very near my home. Google Maps had made an error. My habit of being skeptical and checking saved me from wasting time.

I also recently drove to a distant town for a wedding party and as is my practice before I left got directions from Google Maps or MapQuest and compared it with a physical map. But when I got to that town, construction had closed off many of the streets that I was supposed to go on. This did not bother me because I had a map and quickly found an alternate route to my hotel.

I don't have GPS but was wondering what it would do in situations where its directions cannot be followed due to various reasons. For example, for people traveling in Death Valley, if they sense that the dirt road they are asked to go on is a mistake, what options do they have? Does anyone know?


Trackback URL for this entry is:


I have only used a GPS once while driving. That one recalculated a new route whenever it became clear that I had missed it's last direction. I assume any good GPS would do that.
And, obviously, GPS databases, like any, can contain errors. Of course, so can a paper map. Generally a GPS database should be more up-to-date than a paper map simply because they can be updated more easily than reprinting a bunch of paper maps. Your paper map is only as current as it's last print run.
Many GPS also have the option of downloading current road construction information.
They also have more detailed information and/or a much larger geographic area available than you would likely have with a set of paper maps. If you are travelling around Europe, as I was, you would need a LOT of paper maps to give you all the information that would be available in one GPS database.
GPS also don't require you to pull over or map-read while driving every time you want to figure out your next turn. So they are handy (and safer) if you don't have a navigator in the passenger seat.
Your method of comparing your directions to a paper map (or other source) is good, but not due to the paper map's inherent superiority. It is good because it compares different sources of information, thereby catching possible errors in one (of course, I'm sure you know that).
I'm an old professional air navigator so I have a soft spot for real maps, but GPS does have MANY advantages.


Posted by Steve Eyre on August 21, 2011 12:37 PM


Thanks for the input. As you say, what I was arguing for was to have at least two sources of information.

As for re-calibration, I am curious how that works. Does the GPS tell you to go back to the road that you passed and ignored? If you suspect that a direction is wrong, what do you do? Do you simply go in a random direction and hope that at some point the new route works? How far must you go before it derives a new route that ignores the old one?

Posted by Mano on August 21, 2011 01:16 PM

Shalom Mano,

I remember a story from the mid '90s about how the Park Service was pulling out its hair because hikers were relying on their cell phones to get them out of trouble and not taking the normal precautions when hiking in the wilderness.

Not that I would recommend you watch it, I don't, but I made the mistake of seeing the Blair Witch Project when it came out and came as close as I ever have to yelling at a movie screen when the trio became lost in the woods of Western Massachusetts.

People that stupid deserved what they got. Any Tenderfoot would have known to follow the first stream they came to downstream.



Posted by Jeff Hess on August 21, 2011 01:54 PM

There is a GPS route-finding service bundled into my Android phone. It's the first opportunity I've had to use a GPS. I'm deeply ambivalent.

I don't know anything about the ins-and-outs of the software, but the recalibration does not require you to retrace steps. For instance, I use it sometimes when I have to go to a section of Brooklyn I'm not familiar with. I'll enter the destination address and the software will lay out a suggested path. If I deviate from the path, it will then recalculate a new path based on the direction I'm currently traveling. This is very useful, since there are some streets or areas I know to avoid at certain times of day. The software doesn't yet seem to be aware that the Prospect Expressway is closed everyday in one direction until 11am. Odd, since this is a very long-term construction circumstance.

I think the biggest reason GoogleMaps sends people down old roads is because it doesn't cost them anything at all to publish incorrect material. I imagine that there is a certain level of fact-checking that goes into the research and publication of paper maps, whereas electronic maps are less thorough.

For things that matter (aviation, coastal navigation) I'd expect an even higher level of precision and accuracy than with road maps. Of course, I'm purely speculating.

I read a great book by John Noble Wilford called The Mapmakers. It's a history of cartography. Fascinating. But it leaves off before the mobile internet.

Posted by Peter on August 21, 2011 02:07 PM

As an avid hiker, I would never rely simply on GPS, especially in an area like Death Valley where mistakes can be fatal. Road GPS units like the TomTom usually don't tell you to turn around unless there is no other option; they recalculate based on the direction of travel to get you back on track. But like any device, it's only as good as the data fed into it. If the maps on my GPS ran out and I was in Death Valley, I'd have turned around and retraced my path. The people in the article (especially the one who named her GPS) probably had no business in Death Valley.

Posted by Scott on August 22, 2011 09:08 AM

Being directionally impaired, I am a BIG fan of GPS. For me, GPS is one of the best technological innovations in the past decade. It has saved me enormous amounts of time that I used to spend getting lost, pulling over, reading maps/asking directions, driving some more, finding myself still lost ... and repeating this entire process.

That said, if I am traveling any significant distance, I always cross-check my maps (as Mano does) and bring a printed map with me as well. I'm trying to teach these strategies to my 16-year-old son as he learns to drive.

There are always stupid people who trust too much in technology. This is not specific to GPS. Years ago, when I visited the Grand Canyon, I had an interesting conversation with a park ranger. He told me that park staff often have to rescue people who believe they are visiting Disneyland rather than the Grand Canyon ... people who stand too close to the edge or climb beyond safety barriers. Many of these people die for their poor choices.

Apparently, a young woman recently died at Niagra Falls. She was standing on a barrier/handrail, slipped and fell into the river.

Whether people place too much trust in the technology of a GPS or a handrail, the result can be the same. Injury or death.

Posted by Tim on August 22, 2011 10:03 AM

Tim Farley's excellent site has a page on this-

On a recent trip to Mohican State Park, we first plotted out a route with multiple maps, some paper, some online. We printed out maps as well from various sources. Somewhere along the way we missed a turn, and being out in the country, there was not a good place to turn around for a while. We started using my iphone (which relies on cell towers) instead of my GPS. This helped until we got to an area with no cell reception and I made another wrong turn. I had forgotten about cell reception. So we then had to plug in the GPS which often won't start up while moving. Since there was no place to pull over, I just winged it till we found the place. moral of the story, stand alone GPS units (which use satellites) have advantages over cellular phone ones.

Posted by G on August 22, 2011 02:38 PM

I work with real estate agents and appraisers all the time and they rely on the GPS systems almost blindly as you mention. I myself got stuck driving in circles in France one time but had the sense to stop and ask for directions before I got too "lost". Good reminder.

Posted by Rob on August 22, 2011 04:48 PM

Really having a GPS system is helpful but having not the updated GPS is a problem. This may lead anyone to nowhere. Where their lives may got in danger.

Posted by negrielectronics on November 16, 2011 03:06 AM