[OSM-talk] multipolygon inners that aren't inside.

Frederik Ramm frederik at remote.org
Mon Jul 12 20:37:37 BST 2010


John,

John Harvey wrote:
> Two ways are marked as inners but nothing is inside anything else.  The 
> problem is these kinds of errors present a barrier to entry for anyone 
> using the OSM data - if you try to write a "by the books" renderer for 
> this area you get a spill.

A "by the books" renderer should definitely ignore inner/outer roles and 
just find things out by itself.

> To render it correctly you have to test ways 
> marked the inner are actually inside something marked outside.

Yes.

> If the code in those 
> three renderers (which catch this error and handle it two different 
> ways) was instead in the submission engine the OSM data would be better 
> for it.

Too difficult - too much logic in the submission engine. Imagine, every 
time someone touches any of the nodes that's part of any polygon ring, 
the full polygon validity check would have to kick in.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"




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