Can Using GPS Get You Into Trouble?

In our modern, tech heavy world we often rely on our semi-magical tech devices as if they are fool proof.  Today’s Smart phones combine dozens of functions in one small package that we are connected to almost 24 hours a day.  Last night I couldn’t sleep, waking at 2:30 AM.  I turned to my phone to check the weather (snow coming?), scan my social media accounts, and read a news story till I was sleepy.  On our personal devices we have flashlights, E-mail, news, radio, cameras, and….. GPS, the Global Positioning System.  GPS is a wonderful and useful tool.  It can tell us where we are withing a few meters anywhere on earth, and paired with a good database it can help us navigate to our destination. However, it cannot do everything, and relying on GPS too much can get one into trouble, and the following news story from CNN shows.

“(CNN)A man who became stranded during heavy snow in the backcountry of California’s Sierra Nevada mountains for a week after following the directions on his GPS was rescued alive after surviving on a small supply of food and melted snow.

Harland Earls, 29, was traveling from Grass Valley to Truckee for a birthday party on January 24, a drive that would typically take less than two hours, when a heavy snowstorm shut down
Interstate 80. Seeking an alternate route, Earls turned to his GPS, according to the Sierra County Sheriff’s Office..

The device directed Earls to the shortest route on the map. But the GPS didn’t account for Henness Pass Road being an unplowed mountain pass and Earls ended up being stuck for days in snow so deep he was unable turn his vehicle around, the sheriff’s office said.”

It seems Mr. Earls did what many of us do: Rely on the “magic” in the little device to get us where we need to go, especially when we are in unfamiliar areas. While we all use GPS, in our cars, phones, etc., most people don’t know how it actually works.  I’ll save the technical discussion for another day, but put simply, GPS uses a number of satellites in space, receivers on the ground, and some pretty impressive math to calculate a position on the ground. The accuracy, for most of us, is about +/- 5 meters (~15 feet).  That’s usually plenty good to know where we are, find the right road, or get to grandmother’s house.

However, though the GPS system is very good at telling us where we are, navigating with GPS, especially using roads, depends entirely on the completeness and accuracy of the database it uses. The only job of the GPS system is to locate points on the surface of the earth with an accuracy and precision that is useful to human activity.  The database part, meaning the streets, named places, topography, rivers, etc. are stored in a database that needs to be accurate and up to date.  If not, problems arise.  For example, I live on a dead end street.  Because it was developed as a private enterprise, our street was not included in the US Census streets database, nor that of the county.  As a result, for the first 8 years we lived here, people could not find my house using their car or phone GPS. It usually told them to go to a street south of us, turn right, and drive through a neighbor’s house and backyard, smash down the fence, and end up in my garden. The GPS showed where my house was, but the streets database was incomplete.  Many people ignored the specific directions I gave them (first street west of 12th, named “XXXX Lane), house with the basketball hoop.  They usually said “no, I’ll be fine, I have GPS.”  Many got lost. 

The point of it all:
We should all trust technology where it works for us, but not blindly.  As with nearly all geo-spatial technologies and our use of them these days, data is the key.  We need to consider the data behind our solutions, especially GPS.  GPS can tell you where you are, and often where we are going, but in terms of navigation, it is only as good as the database it uses; and it cannot tell you the conditions on the ground, weather, etc.  It will be really cool when this much detail is possible, but for now we need to be cautious, and use multiple sources of information when heading out, knowing that GPS has only some of the answers. There is a lot to be said for a good paper map and recent information on local conditions.

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