"Why not relation?"
I think using a relation will avoid the messy use of numbers in the key space. The relation type Relation:multilinestring would be a perfect fit for this. Multilinestring relations can be nested so this would avoid having too many elements in a relation.
By the way, I agree with tagging the coastline only instead of making it a closed region. I actually thought of something similar when I was wondering how to tag peninsulas. —seav (talk) 17:18, 7 March 2014 (UTC)
- I agree that using relations would be better, the member problem can be overcome with sub-relations like sections of coastline (btw.: also those merit being tagged and should get a name, wikipedia-link etc.). Either we'd use Relation:multilinestring or maybe Relation:route where it is requested that the route is continuous? --Dieterdreist (talk) 14:58, 9 March 2014 (UTC)
A few questions
- How should this tagging be processed for rendering labels and other purposes? Will this processing be robust, for example if the tagging is not consistent? In case of large peninsulas there would be hundreds, possibly thousands of coastline ways and it is unlikely all of them will be consistently tagged.
- How should the mapper choose the number in the key, i.e. if i want to map Istria how am i supposed to know to use the key peninsula:2?
- In addition to the previous question - how am i supposed to proceed if the numbers are already used - for example i want to tag the Italian peninsula and peninsula:0 is used for Europe and peninsula:1 is used for Salento?
- big features with fuzzy borders are not fitting well with OSM. We get the same problem for deserts, valleys, etc
- I've never seen a tag working well with a level in its key. Since OSM is a spatial db, you should not ask the contributor to put the range or pseudo-hierarchy in the tag itself. This will fail because contributors do not check for smaller or bigger entities coverage (btw how to retrieve the shape if it's not a relation ?) to find out which range has to be set for a new entity or re-arrange the existings ones in case of conflict.