[Talk-GB] Ficticious embankments? Vandalism.

[ael]

On Tue, Mar 17, 2020 at 09:53:07AM +0000, John Aldridge wrote:
> On 17-Mar-20 02:08, Warin wrote:
> > A single GPS trace is fine if that is all there is, better to average many GPS traces, in some locations I have 50+.
> 
> Though, AIUI, once you've reached this level of precision, remaining errors
> are likely to be systematic (e.g. satellites in a particular direction being
> generally received via a -- delaying -- reflection rather than directly). No
> amount of averaging will help with that.

Well, the Garmin averaging goes some way to improve on that. That is one
of the reasons that waypoint averaging can be done over several visits:
it gives some sort of averaging over reflections, atmospheric changes
even satellite calibration.  Not up to professional differential GPS, of
course, but potentially accurate to maybe a meter. Certainly way better
then using imagery with the poor resolution, parallax errors and all the
rest, which is probably what the user used.

ael