[Talk-us] Systematic errors in the Maui, Hawaii Data

[Scott Atwood]

Hawaii (Big Island) seems to be affected by the same or similar
displacement:
http://www.openstreetmap.org/?lat=19.09422&lon=-155.78022&zoom=15&layers=B000FTF

-Scott

On Tue, Sep 29, 2009 at 11:42 AM, Dave Hansen <dave at sr71.net> wrote:

> On Tue, 2009-09-29 at 11:20 -0700, Scott Atwood wrote:
>
> > I spot checked a number of locations all around Maui, and in all the
> > locations I checked, they seem to be affected by the same or highly
> > similar offset to the NNW.  Here is another example from the Lahaina
> > area:
> >
> >
> http://www.openstreetmap.org/?lat=20.88606&lon=-156.68522&zoom=15&layers=B000FTF
>
> If you can look into formalizing this, I'd be willing to take a look at
> it.  What I mean is to take some precise measurements from a wide set of
> samples across the island, probably 20 or 30.  Figure out what the
> displacement vector is at each point, and ensure that it *is*
> consistent.  The worst thing we could do would be to perform such an
> edit and later realize that we've hurt more than we've helped.
>
> I'm just really hesitant to go moving an entire island worth of data
> based on the problem I've seen so far.
>
> > The prospect of manually shifting every single street on the entire
> > island of Maui (even in batches within JOSM) is extremely daunting,
> > and strongly inhibits me from wanting to do any work on Maui.  And the
> > fact that such enormous errors persist suggests to me that few if any
> > people have done much non-automated work on Maui yet.
>
> The question is whether it will take longer for people to do it manually
> or if doing it in an automated way will be more efficient.  Believe me,
> the prospect of doing a mass edit like that is pretty daunting as well.
>
> > Can we verify how much editing has been done on Maui? If it is as
> > little as I think, there is little to loose by throwing away the
> > existing data and starting over. I still think re-importing (or some
> > kind of automated batch editing) might be a faster and easier way to
> > fix the problems with Maui.
>
> Sure.  Just download the entire island and see how many objects have
> been touched by people other than DaveHansen.  JOSM can tell you this
> pretty quickly.
>
> -- Dave
>
>


-- 
Scott Atwood

Cycle tracks will abound in Utopia.  ~H.G. Wells
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