[OSM-talk] [Spam] Re: Invisible coastline errors in Potlatch

Karl Newman siliconfiend at gmail.com
Wed Dec 31 19:13:12 GMT 2008


On Wed, Dec 31, 2008 at 11:00 AM, Peter Miller <peter.miller at itoworld.com>wrote:

>
> On 31 Dec 2008, at 18:20, Cartinus wrote:
>
> > On Wednesday 31 December 2008 18:40:18 Peter Miller wrote:
> >> Dodgy circular ways
> >> ---------------------------
> >>
> >> There are a number of islands off the Swedish coast that are showing
> >> up as errors:
> >>
> http://tile.openstreetmap.nl/coastlines.html?zoom=16&lat=57.80195&lon=11.66
> >> 246&layers=B00
> >>
> >> If one switches to a OSM view
> >> (
> http://www.openstreetmap.org/?zoom=16&lat=57.80195&lon=11.66246&layers=B00
> >> ) one can edit them. Using 'h' I can see that they haven't been
> >> touched for months, however if I click on them the tagging looks fine
> >> and the way is shown as circular.
> >>
> >> Here is the history of one of them:
> >> http://www.openstreetmap.org/browse/way/25610508/history
> >>
> >> Notice that the way appears to be a triangle, but that the way has
> >> four points on it.
> >>
> >> If it does have an extra segment in the way then why does it show up
> >> as a circular way in Potlatch? The simples thing will probably be to
> >> delete them and recreate them but I though it was worth pointing it
> >> out first.
> >
> > With any circular way the first and the last nodes are the same. So
> > to define
> > a triangle you get four nodes in the xml.
>
> Makes sense!
>
> >
> >
> > Those Swedish islands show up as errors because they are too small.
> > Anything
> > with a diameter of less than approximately 10 meter shows up as an
> > error.
> >
>
> However the checker explanation doesn't say that (
> http://wiki.openstreetmap.org/index.php/Coastline_error_checker
> )
>
> What should one do...
>
> 1) Delete all features smaller than 10 meters
> 2) Keep them in a have loads of people go an investigate false problems
> 3) Make them bigger so the islands as accepted by the coastline checker
> 4) Adapt the coastline checker to that is accepts smaller islands.
> 5) Add a tag to tell the coastline checker to ignore this feature
> because it really is a small island.
>
> I vote for 4), everything else is a cop-out (1 and 3) or will waste
> lots of people time (2) or be confusing (5).
>
> By the way, who maintains the coastline checker and how does one talk
> to the people who maintain the code? Shouldn't there be information
> for all tools about how to report problems, how to request features
> and details of maintaining them?
>
>
> Thanks,
>
>
> Peter
>

What about 6) Convert tiny islands to a node tagged as a rock or navigation
hazard.

Karl
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