[OSM-talk] to all potlatch and JOSM users - automatic simplification of geometry

Stefan de Konink stefan at konink.de
Sun Aug 9 11:12:32 BST 2009


On Sun, 9 Aug 2009, Richard Fairhurst wrote:

> Stefan de Konink wrote:
>
> > And then you realise that the alignment of Yahoo Imagery is wrong
> > on most
> > places, and you have killed good vector material. Great job :)
>
> "Good vector material"? Tell me, have you ever _seen_ TIGER?

Yes, and I have also _seen_ Yahoo been wrong on more places than it was
right. So I am still skeptical people tracing Yahoo and claiming they are
better than [insert source here] mainly because except that source they
have 0 ground reference.

> Seriously, you're kidding me. Yahoo may be out-of-alignment here and
> there but by and large if the street looks straight in Yahoo, it is
> straight. And US city streets generally are. TIGER streets are
> bonkers mad wavy.

Most likely this is true because the TIGER dataset was actually traced
from/for a much lower precision map, hence wavy because you are plotting
it on a far higher resolution then it was created for. With respect to
TIGER you might say: TIGER is *so* bad, Yahoo will always be better. My
point is, unless Yahoo is actualy validated where you are tracing it
gives poor output too, no matter how bad you think TIGER is.



Stefan





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