On 17/3/20 8:53 pm, 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.
Yes, a source of error. When placed over some reasonable imagery any
discrepancies can be seen, evaluated and if necessary compensated for.
However most users will not be aware of the discrepancy as they would be
using another GPS to 'see' it.
If the GPS tracks are separated by days, weeks and months then the
satellites will have changed, and the satellite positions too. Usually
there will be 'outliers' that are more than 2 standard deviations from
the average. It is valid to delete these from computations.
I don't bother with the calculations and do it by eye, more satisfying
than loading it all into a program, taking the result and entering it.
And I like to see the raw data anyway.
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