Originally Posted by BCRider

I'm curious about how you folks that are using Google Earth know that it's accurately calibrated? Let alone the fact that a three figure working distance implies at best a limited accuracy. For example 3.11 miles plus or minus .01 miles implies an error of plus or minus 53 feet. And that's only good if you can actually trust that Google Earth is accurately calibrated to that level. It's also allowing for up to a possible 3% error over that distance even if you CAN trust it to be accurate to the two decimal places. If we want to be truly anal about our input setting for these things then I'm sorry but that is not good enough.

At that point I'd rather trust someone marking my valve position, roll for three revolutions while sitting in the saddle with my weight in the usual riding position and regularly used tire pressure and then use a steel tape to measure the distance to the nearest 1/16 inch. At that point I'd be working with roughly a 3360mm distance plus or minus the allowable 1.6 mm (1/16 inch) error. That's a possible plus or minus error of only .05% and I've got far more control over the results. Now THAT is being suitably OCD about the whole exercise....