[OSM-talk] relating trace points to gpx files

[Joerg Ostertag]

On Monday 24 July 2006 14:39, Andrew Loughhead wrote:
> 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.

Something that might work would be to save these points into a local xy.gpx 
file then do osm-filer.pl --split-tracks xy.gpx and load the resulting file 
into josm again. This should split the tracks everytime the distance get too 
high.

-
Joerg