[OSM-dev] "The Future of Areas" - open discussion?

Ben Supnik bsupnik at xsquawkbox.net
Mon May 9 13:25:57 BST 2011


Hi Jukka,

On 5/9/11 5:36 AM, Jukka Rahkonen wrote:

> In addition to these native relation based polygons we have them also as
> true polygon features. Polygons are created automatically from the
> linestrings by a database operation. Polygons are automatically updated if
> the lines are edited and topology checks are preventing the operation if
> edits would lead to a non-valid polygon topology.

We do this in our post-processing too, but the results are mixed.  Since 
the map is basically drawn as painted layers, it's very common to find a 
border-delineating feature (like a road that forms the edge of a park) 
not having the same path (either the same nodes or the same actual 
positions) as the park multipolygon. The result are very small slivers 
of polygons along the edges of features.

As a result, we've had to put in a bunch of code to 'sanitize' the 
topological-polygon results for our users.

cheers
ben

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