[OSM-talk] source=(survey, yahoo, gps...)

[Anthony]

On Wed, Sep 9, 2009 at 2:52 AM, John Smith <deltafoxtrot256 at gmail.com>wrote:

> 2009/9/9 Anthony <osm at inbox.org>:
>
> > If the way lines up with the GPS trace, the GPS trace was used as the
> source
> > of data.  If it doesn't, it wasn't (or it has been changed).
> >
> > Am I missing some reason that's not correct?
>
> You're assuming only one type of source was used to generate a way,
> when multiple sources may have been used on the same way, so what do
> you assume if some of the way lines up with GPS trace and some
> doesn't?
>

Depends how much it matches up.  And whether or not I care enough to
investigate further.  I'm not sure what the point of the question is,
though.  I agree that it's useful to tag ways, and/or give further
explanation in your change message.  There's not much of a perfect solution
for these sorts of things, though.

> I agree that people should list their source, even if they uploaded a GPS
> > trace, since not everyone uses the same software and can bring up the GPS
> > traces very easily.  But if the source is a GPS trace (or Yahoo, for that
> > matter), it's not the end of the world if they don't, as a quick
> examination
> > of those two possibilities will reveal the source.
>
> What if they edit the way in JOSM and only load the GPS trace locally,
> how are you know know they created a way based on GPS information?
>

You didn't really give enough information to answer that question.

Again, I agree people should list their source.  They also should upload
their GPS trace.  Ideally they should do both.  If they only did one, and
not the other, I'd prefer they upload the GPS trace.  But yeah, ideally,
they should do both.

> It's a shame if
> > everyone who looks at that has to go through all the same trouble as me
> just
> > to confirm that yes, this GPS trace is for a road that no longer exists.
>
> Which is the point of tagging ways/POIs with source information.
>

Tag what way?  The way no longer exists, since the road no longer exists.
 It was most likely destroyed during the construction of the new highway
which was what I was out there mapping (it's especially cool having OSM more
up to date than Google and Yahoo in that area, and knowing that you're the
one who updated it).  And in fact, whoever uploaded that GPS trace never
edited the way in the first place.  The way was created from Tiger data.
 You don't expect people to tag ways that they *don't* edit, do you?

Another possible solution would be if we could mark ways as obsolete or
historical rather than deleting them.  But I checked the wiki and apparently
this was proposed and rejected.  And I kind of see the argument against it.
 I don't know.
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