[OSM-talk] relating trace points to gpx files

[Andrew Loughhead]

On Mon, 2006-07-24 at 14:02 +0200, Erik Johansson wrote:
> On 7/24/06, Petter Reinholdtsen <pere at hungry.com> wrote:
> >
> > [Erik Johansson]
> > > You should always create OSM data layers from a GPX file you yourself
> > > have created. Never from traces that is downloaded from the server.
> > > And I'm not quite sure why it's not strictly verboten. Imi?
> >
> > What a strange idea.  I've drawn most of Oslo based on GPS points
> > downloaded from the server, and believe it is a very sensible way to
> > create the OSM data layer.  Almost none of the GPS points gathered in
> > Oslo have been collected by me, and I fail to see the problem with it.
> 
> Well I was under the impression he was using the JOSM feature to
> create a data layer directly from the GPX traces. Given the amount of
> data you have in Oslo/London/Köpenhamn drawing manually is an
> requirement.

It was only a question, based on what I had seen happen while
experimenting with options in JOSM. Neither the OSM nor JOSM wiki
explained this, as far as I could find. I think it was your assumption
that I was "using the JOSM feature" for anything in particular. Your
reply, along with several others, clarified what was going on, the key
points being that the data that JOSM receives is just a bunch of points,
JOSM with the "draw lines" option enabled links them in order of
receipt, and that order may accidentally be meaningful, or may not. Its
clearly not something to rely on. 

I will try to write something on this for the wiki. 

cheers
Andrew.