Don’t let your GPS lead you astray

Don’t let your GPS lead you astray

By Greg Illes

My first GPS was the size of a brick and took ten minutes to get a fix — then it gave me only latitude and longitude, which I had to plot against paper maps. A couple of decades later I was using a hand-sized unit to guide my aircraft through cloud-filled skies. Today I have a domino-sized GPS on top of my camera to location-stamp my photos. My, how things have changed!

That fabulous device on our dashboards is an amazing technological development, one on which many of us have grown to strongly depend. After all, it tells us where we are and how to get where we want to go, and it is almost always right.

The key word there is “almost.” Unfortunately, GPS devices, while rarely wrong about your current location, have many ways of messing up in telling you where to go. Here are some caveats on GPS usage:

Short versus fast — These choices can each lead to bizarre results. One time, the “shortest” routing repeatedly took me off and on freeway ramps. Apparently, the ramps were a tad shorter than the primary roadway. The “fastest” routing choice will always assume you are going the speed limit. On many interstates this is 70 or 75, and for a variety of reasons (fuel economy, sightseeing, towing restrictions), many of us don’t drive that fast.

Gates and private property — GPS units, and paper maps to some extent, do not show access restrictions. This is especially an issue on smaller secondary roads. When navigating such areas, use a paper map that shows land usage so you can tell when you are routing across private property.

Low overpasses and no U-turns — Only a few GPS units claim to address these blocking issues. Watch out when navigating the secondary roads that you are not led into a long dead-end.

Database errors — Occasionally, the information in the GPS is just flat wrong. The only way to tell is to cross-check it against another source such as a paper map, Google Maps or a GPS with a different database.

Don’t give up on paper: It’s always a good idea to use a paper map in conjunction with your GPS. The paper map gives you a wide-angle, bird’s-eye view of what’s going on and can help you avoid the pitfalls of GPS over-dependence.

As always, do your serious navigating while comfortably parked. If you get in a fix on the road, pull over to sort it out.

(Editor note: Check out a huge selection of RV GPS systems on

Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his blog at