[talk-au] Hi all ...

[Ross Scanlon]

On Sat, 20 Jun 2009 21:09:50 +1000
Sam Couter <sam at couter.id.au> wrote:

> > Averaging the traces will not necessarily make the map more accurate.  If
> > there are two that correspond closely and one that's 20m off then the
> > resultant way will be incorrect.
> 
> I think you've shown yourself to be smart enough that you know this is a
> strawman.
> 
> The term "average" usually means the mean, which would cause the result
> you describe. I don't think you fooled anyone into believing that would
> happen, or even that you think that would happen. When using GPX traces
> it makes most sense to use the mode or something approximating it, or an
> intuitive weighted average. Any of these methods would discard the
> outlier and result in more accurate maps on average (there's that word
> again, meaning something different again).

I was wondering how long it would take someone to pick up on this.  Yes people tend to use average when in fact they should be using mean or mode.

In this case the "average"/mean/mode would negate any significantly inaccurate trace.

And a human looking at it would pick it up in about 0.001 second.

I can see there are reasons for uploading gpx traces but in the meantime I'll still hold mine, as they tend to show where I work and live.  I know I could filter that out but it takes time and I've got to find all stops I make at customers premises/residences.

I think we'll leave it at that and leave each to their own.


Cheers
Ross