[OSM-dev] Mapnik layer has become confused by layers?

D Tucny d at tucny.com
Fri Feb 13 05:44:16 GMT 2009


2009/2/13 D Tucny <d at tucny.com>

> Hi folks,
>
> Not sure when this started, but, mapnik seems to be getting layers wrong
> when drawing objects...
>
> e.g.
>
> http://www.openstreetmap.org/?lat=30.297629&lon=120.155582&zoom=18&layers=B000FTF
>
> In this view there is a two dual carriageway primary roads that meet at a
> junction at ground level (no layer tag), above the junction running north
> south is a dual carriageway trunk elevated road/viaduct (layer=2), above the
> primary roads, with some below the trunk and some above is a junction
> consisting of a number of trunk_link roads (various layer tags) linking the
> east west primary road to the trunk road... Mapnik appears to be currently
> drawing all trunk_link roads below everything else, even though they are
> tagged with layer tags of 1, 2 and 3 depending on which other ways they pass
> over, though it's difficult to see if it's drawing them under the trunk as
> there are no borders visible making it all appear to be at the same layer...
>
>
> Similar confusion is also visible in other places where the same road
> crosses other roads and there are link roads present...
> e.g.
> http://www.openstreetmap.org/?lat=30.27611&lon=120.16596&zoom=17&layers=B000FTF- east west primary linked to north south trunk (bicycle flyover and
> roundabout between the two)
> e.g.
> http://www.openstreetmap.org/?lat=30.21797&lon=120.171&zoom=17&layers=B000FTF- No link roads present here, but, double decker bridge with primary road at
> layer 1 and trunk at layer 2 rendered with the primary road above the
> trunk...
> e.g.
> http://www.openstreetmap.org/?lat=30.27895&lon=120.19501&zoom=17&layers=B000FTFT- Primary links roads at layer 1 overlaid by unclassified roads with no
> layer tag
>
> osmarender seems to get it right, even if it does look a bit messy where
> the different layers join...
>

The cloudmade minutely mapnik also get's this right...

e.g.
http://matt.sandbox.cloudmade.com/?lat=30.29722&lon=120.15529&zoom=18&layers=B0

And a different area with layer issues that's not a road...

http://www.openstreetmap.org/?lat=30.266499&lon=120.129264&zoom=18&layers=B000FTTT
http://matt.sandbox.cloudmade.com/?lat=30.266499&lon=120.129264&zoom=18&layers=B000FTTT
Showing a building with parking on much of the top, the parking area has
holes using a multipolygon relation where parts of the building are taller
than the parking level...

d
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