[OSM-talk] Layers and landuse

[Richard Z.]

On Sat, Jun 27, 2015 at 10:40:52AM +0200, Ture Pålsson wrote:
> I recently taught my rendering hack about the ’layer’ tag, and immediately encountered a set of new problems. For example, consider this ditch: http://www.openstreetmap.org/way/243331898 <http://www.openstreetmap.org/way/243331898> . It has layer=-1, probably to indicate that is passes under the road which it crosses. However, it is entirely covered by a landuse=farmland with no layer tag, which I take to mean an implicit layer=0. This means that my renderer now renders the farmland over the ditch, completely hiding the latter. Meanwhile, Mapnik obviously does what the tagger intended.
> 
> Is this a tagging error, that I should fix by editing the data, or is it something that my renderer should be able to cope with?
> 

it is an error and your renderer should be able to cope with it as it is
a pretty common error.

Simply ignore any layer tags which are not in combination with bridge,tunnel,covered,
steps,indoor or similar - the key:layer wikipage has a longer list of combinations 
that seem legit.


Richard