[OSM-talk] Defective GPS trace

[Shaun McDonald]

On 1 Jan 2010, at 13:07, Steve Bennett wrote:

> I've got a trace from today which is significantly out of sync with a path I traced from Nearmap:
> 
> http://www.openstreetmap.org/edit?lat=-37.880138&lon=145.193417&zoom=19&gpx=594988
> 
> The trace looks like I was wandering through the grassy paddock, but I was actually following exactly that northern most "highway=path" in the bush. So it looks like the trace is incorrectly recorded something like 50m north of where I actually was. Now, since the discrepancy seems to go away on that track a bit further east (later chronologically), presumably the explanation is the GPS data is faulty. Is this common? I'm new to GPSing, so I'm just surprised. It's a Garmin Oregon 550. Is there anything I can do to reduce, or at least detect, such errors?

It is very common for GPSs to give errors for whatever reason. Interference is very common from things like buildings. Newer units are less likely to have an issue. You simply need to go along that track again a few times to get an averaged out reading.

Shaun

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