[OSM-dev] OpenStreetMap Carto, lines and polygons

[sav123]

Dear All,

I'm working on osm data transformations and focused only on renderring a map 
with osm-carto

Could you help me please ? I have one question :

what an OSM-carto css author expects to find exactly in the tables line and 
polygon ?

---------------

The generators scripts cannot help to understand since their outputs differ.
On another hand, such algorithms follow necessarily discussions and 
conventions.

Else, if there is not an exact definitions page, I should be interested by 
pages about this kind of questions :
- in a relation, is a reference to a relation a shortcut to its own content 
?
- does it make sense to build a way with the nodes belonging to polygons ?
- in what cases exactly a way data belongs to both line and polygon tables ?
- is there a mandatory way to split wkb data when it is too long ?
- in what cases tags which aren't explicitly requested are useful ?
- is there identified data belonging both to postgres tables and to other 
databases ( ie shape simplified_land_polygons.shp ) ?

I think I understand what are lines and polygons in general and I know the 
db style and lua transformations preconised by osm-carto

Thank you
Igael