Originally Posted by pdlamb

2. GPS plus topographic maps. Sometimes fairly decent, sometimes laughable. My favorite was a climb where the mapping software tried to interpolate between contour lines, with the result that a 1,200' climb registered as 2,700'. The road followed an old logging railroad line, so it was a consistent 2-3% grade most of the way. The elevation plot that thing put out looked more like the logging saw than the railroad elevation.