Don't render border between two connected forest polygons

[atorger]

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A quite common drawing technique used by mappers is to split up large forest landcovers in several polygons, where the seamline doesn't actually mean anything in the real world. The default OSM-Carto style doesn't render these lines so it looks like one single large polygon, so it's become a quite widespread accepted drawing technique.

Here's an example from Finland: https://opentopomap.org/#map=15/64.09961/24.91060 where the forest polygons have been split into tiles, and thus the borders are visible here.

I think it would be desirable, if possible, to skip rendering borders between forest-to-forest polygons.

[atorger]

I note the same issue between water-to-water polygons

[masterofnoroad]

here in Poland forest data was imported from national forestry database. So each polygon means separate forest unit. They are divided usually with a forest road so even when road its not drawn on topomap you can see it by the rendered border. So actually it is positive for me, and its so light it doesn't bother me in other places. Maybe just render it from certain zoom level?

[tomass]

It is not a simple decision to „render or not render or when“.

OSM-Carto symbolises only forest polygon internal area while OpenTopo also symbolises the outline. This is why you see „border“ between two polygons. The only way to avoid that is to pre-process the forest polygons (ST_ClusterWithin+ST_Union/ST_Buffer). It is up to OpenTopo creators to say if such processing and additional space required are ok.

Note that in Finland example there is actually a space between forest parcels. This could also be dissolved with pre-processing.