2009/12/28 Robin Paulson <[email protected]>: > 2009/12/28 Frederik Ramm <[email protected]>: >> Pure GPS elevation is worthless due to bad precision (for technical reasons, >> Z measurement is much worse than X/Y measurement in GPSes). Some GPSes have > > ok, i didn't realise that. what levels of bad precision are we talking > about; i assume it varies form model to model; how does it compare to > the precision of srtm?
Attached is a plot of my bike ride with three devices (different models unfortunately) recording altitudes. (x is degrees longitude, y metres) One thing to consider when using the traces from osm's collection is that not all of them are recorded on the ground level, there are at least a couple of airplane traces and a paraglider trace. Cheers
<<attachment: trace-test.png>>
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