[Tile-serving] Mapnik renders labels for each exclave on lower zoom levels

[Paul Norman]

On 2016-02-24 10:13 AM, Roman Woessner wrote:
> Hi,
>
> we currently have a question on rendering the openstreetmap-carto 
> default style on our own server.
> For countries and states having one or more exclaves, our mapnik 
> renders multiple labels for these objects which results in a map 
> similar to the following example of europe on zoom level 4:
> http://i.imgur.com/Xylkzpu.png
>
> Our tile serving setup is the following:
> - Latest europe pbf in a PostgreSQL 9.3 and PostGIS 2.1
> - Latest osm2pgsql (built from source) using the default import style
> - Mapnik 3.0.9 (built from source) using the latest (24.02.16) 
> openstreetmap-carto style
> - Latest renderd and mod_tile (built from source)
>
> In spite of using placement="interior" for these labels, the labels 
> are not renderd as we would expect.

In osm2pgsql with default options multipolygons (and boundaries) which 
form disjoint polygons are turned into multiple rows with POLYGONs 
instead of one MULTIPOLYGON. 
http://paulnorman.ca/blog/2014/03/osm2pgsql-multipolygons/ explains some 
of the differences and reasons.

https://github.com/gravitystorm/openstreetmap-carto/issues/59 is the 
issue tracking the similar isue.


This being said, it's not clear to me why you're getting duplicate 
labeling as the way_area restriction should prevent labels for tiny 
polygons.