A frequent comment is that my GPS unit is off because it doesn't match up with the highway or it shows me in the water when I'm still at the boat launch. Two things need to be considered: GPS accuracy, even with the best satellite system, is typically about 15 feet. This is enough to put your position icon off the freeway. Mapping errors are also a factor. If the map's anchor points were not accurately placed when the map was created it could be off by many feet. Believe the GPS unit.
Bill Diedrich is a retired Minnetonka math teacher with a love of fishing electronics.
