Technogeekery and the Limits of GPS Technology


WC bows to no one in his love of technology. HP calculators, fancy sound systems, Apple and Macintosh computers, computer programming, digital cameras: WC has greatly enjoyed any number of 20th and 21st century technologies. Including the global positioning system or GPS technogeekery.

But WC likes to think he understands the limits of technology. In a technology involving more than one element – the global position system, for example – amateur technogeeks confuse the accuracy of one element with reality of the total system. Sometimes with disastrous results. Any complex system is only as precise as its least precise element.

The precision of GPS can place you within 30 feet or less of your absolute position. It is very precise. With an additional element, it can nail your position to within three feet. But GPS by itself isn’t especially useful to laypersons. GPS is more useful when it part of a route-planning tool, a navigation tool. Those tools combine three elements: GPS, scanned maps and routing software. The first is very precise; the second two, not so much.

Typical GPS Navigator

Typical GPS Navigator

Scanned maps, in the first case, are only as accurate as the original maps. Especially away from urban areas, the United States Geological Survey – the folks in charge of the best maps available – can’t always keep the maps up to date. And scanning technology isn’t perfect, introducing another opportunity for errors. On a topo sheet, a decent gravel road might be a red line three pixels wide; a dicey dirt road might be a red line two pixels wide. And the further you get from urban areas the less likely it is that the folks scanning the maps have field-checked their digital images.

The third element is the routing algorithm used by the navigation tool manufacturer. Those algorithms vary widely in their sophistication. Some won’t route you along a travel path that involves sketchy roads (assuming the software can recognize a sketchy road). Others will cheerfully route you along a path a mule would worry about. The algorithms aren’t exactly critical thinkers. When you have the bad luck to get a poorly scanned map and a flawed routing algorithm along the same path, well, you have the recipe for disaster.

An unsophisticated user confuses the near-perfection of location with the far from perfect maps and routing software. And get led to a bad, sometimes tragic, end.

Albert and Rita Chertien followed their GPS navigator down Idaho State Highway 51, which heads due south away from the I-84 corridor, crossing the Nevada state line several miles to the west. The Chertiens figured there had to be a turnoff from Idaho 51 that would lead them east to US 93. Idaho 51, in Davy Crockett’s phrase, goes from a road, to a trail to a path, to a squirrel track, up into a knot hole and disappears. Albert died, Rita barely survived.

In Death Valley National Park they call it “death by GPS.” Ars Technica reports:

They are accidents or accidental journeys brought about by an uncritical acceptance of turn-by-turn commands: the Japanese tourists in Australia who drove their car into the ocean while attempting to reach North Stradbroke Island from the mainland; the man who drove his BMW down a narrow path in a village in Yorkshire, England, and nearly over a cliff; the woman in Bellevue, Washington, who drove her car into a lake that their GPS said was a road; the Swedish couple who asked GPS to guide them to the Mediterranean island of Capri, but instead arrived at the Italian industrial town of Carpi; the elderly woman in Belgium who tried to use GPS to guide her to her home, 90 miles away, but instead drove hundreds of miles to Zagreb, only realizing her mistake when she noticed the street signs were in Croatian.

WC is certain that there is a psychological element involved, some kind of authority-reliance mechanism getting out of control. But for WC, it’s mostly the failure to understand that GPS technology – any technology – is only as reliable as its least reliable element.

And sometimes that’s not very reliable at all.

 

Advertisements