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

Peter Miller peter.miller at itoworld.com
Wed Dec 31 19:00:24 GMT 2008

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?



> -- 
> m.v.g.,
> Cartinus
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