[mkgmap-dev] line features are converted to a closed way

Mon Sep 20 06:52:15 BST 2010

maning sambale (emmanuel.sambale at gmail.com) wrote:

> This way is a line tagged as man_made = breakwater:
> http://www.openstreetmap.org/browse/way/55131773
>
> I have in my style polygons file a generic assignment for man_made=*
> [0x13 resolution 24]
>
> The compiled map tried to close the line to form a polygon:
> http://www.flickr.com/photos/esambale/5006580843/
>
> Any idea how to fix this?
> --
> cheers,
> maning

mkgmap assumes that any OSM object that matches a rule in the polygons  
style file must be a polygon (it has no other way of telling).  The  
only current way to fix this is to edit your polygons rule so that it  
no longer matches such OSM objects, perhaps
man_made=* & (area=yes | area=true) [0x13 resolution 24]

In the past I've had a similar problem with man_made=pier, which  
sometimes in the OSM data is a closed polygon, sometimes not.  A rule  
which matches the closed polygons results in nasty artefacts when the  
OSM data is not closed, whereas a rule that only matches lines misses  
all the closed polygons.

Personally, I would love it if some logic could be added to mkgmap for  
it to be able to detect whether something is a closed polygon or not,  
which would make it much more robust in these instances.

-- 
Charlie