[Talk-ca] Modifying GeoBase Ways.

[Michael Barabanov]

With averaging, if the random errors dominate the systematic errors, you
will in fact have a better idea where the road is.  IIRC, during the course
of several hours ionospheric delays would cause systematic errors, but if
you instead drive/ride the same road on different days, it's going to be
relatively random.

Around Vancouver, I know of at least one place where Geobase is less precise
than data I have from my GPS (my 20+ tracks can not be all wrong and
offseted _in the same direction_). Needless to day, I moved the GeoBase road
to match the averaged tracks in that place.

Michael.

On Mon, Nov 16, 2009 at 7:26 PM, James Ewen <ve6srv at gmail.com> wrote:

> On Mon, Nov 16, 2009 at 6:48 PM, john whelan <jwhelan0112 at gmail.com>
> wrote:
>
> > Multiple approximations can often be very accurate when averaged.
>
> I agree... put a commercial grade GPS on a spot, and record the
> results over a long enough period, you can come up with a close
> approximation of where they device was located.
>
> However, driving up and down a road 5 or 6 times is not going to give
> you a superior representation of where the real road is located. You
> are not going to get the exact same locations recorded on each
> subsequent trip down the road, so each location has to be looked at as
> a point of dubious quality.
>
> The OSM project is always going to be of "dubious quality" because of
> the equipment used to capture the data, and the abilities of the
> person doing the data entry.
>
> Those needing super accurate data need to be looking elsewhere. This
> project will never be able to provide sub-metre accuracy.
>
> From my observations, the GPS accuracy that I regularly observe puts
> me within 5 to 15 feet or 2 to 5 meters of reality. This would be in
> line with the GeoBase stated accuracy factor as well.
>
> James
> VE6SRV
>
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