Quote:
Originally Posted by Rossco
Out of interest do you set your speed by GPS or the cars speedo?
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If you're using your GPS, do you do it on a perfectly horizontal road?
GPS can be inaccurate when travelling on an incline/decline, as it's calculated using time between x,y locations (distance on a horizontal plain).
The distance (km's) via road between point A and point B is going to be a lot longer if you're travelling up and down hills. Most Navman, TomTom GPS' don't take altitude changes into account.