[Closed] Metres climbed: Garmin Edge 800 v Memory Map

had this alot myself recently.....my edge often says ive climbed alot more than if i plot the route on bikehike or use the elevation correction option.....

there is one point on my ride i often do that i know is quite steep and certainly a climb that goes up and down for about 1 mile off road...however on bikehike/gpises etc when i plot it, it states 0ft of climbing between this mile....

so now im not actually sure if the gps is right (as its gather data as you ride) or the correct elevation data (and websites i plot the route on) are wrong?!?!?!

My tuppence...........

My edge 305 uses GPS altidude data which is accurate to say 5m s.d. so the time weighted average is you stood still should be 100% accurate. However your not still, so its just plotting lots of elevation changes even as you ride allong a perfectly level road as theres no chance to take multiple readings.

IIRC the more expensive GPS's use a barrometer, which is a more constant measurement (if you stand still it'll stay still) but less accurate (upwind or downwind of a hill or a weather front for example) so it calibrates itself against the GPS regulalry, a bit like GPS's that auto calibrate wheel size over time when sued with a speed sensor.

IME expensive GPS's agree with maps within a pretty good degree of accuracy. Certainly accurate enough to start debateing whether you cycled allong a contour line on the map, thus crossing it often and gaining 10m 'climbing' each time you did or maybe zig zagging up and down between 2 contour lines doing a lot of climbing that woudl not be picked up by the map. Cheeper ones like mine I assume the climb or decent was 2/3 of the GPS recorded value over a few hours which pretty much agrees with the 'corrected' elevation.

Map Mine often has me doing a circular route and leaving and arriving at different heights.