Thibouille wrote: > I have no experience at all with the use of any GPS. > However, I recently had to look at the theory and how it works... My > memory faded a bit but I remember clearly that altitude was indeed a > problem and *can* be quite different mesured by the GPS or the 'good' > one written on the maps. > > I shall dig a bit and find why exactly...
There are two factors, there. One is the barometer: its accuracy combined with how recently you've calibrated it. The other is the GPS system itself. The GPS system measures altitude based on an idealized, mathematical idea of where the surface of the earth is that doesn't always agree with what's really in that spot, particularly spots that are high or low. Also, due to geometry, a GPS receiver can't divine as much altitude data as it can position data. -- Thanks, DougF (KG4LMZ) -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
