Subject of this proposal is to find tags for mapping peninsulas of any size. This tag targets big geographical features which OSM doesn't yet have mapped, others being mountains, seas, deserts etc.
At the moment there is no agreed way to tag a peninsula, although it's an important geographical feature.
This proposal adds no new objects, just tags. This agrees with what a peninsula actually is, not an object per se, but a coastline shape. That's why peninsulas should be tagged on coastlines, their natural boundaries.
Number in keys
A problem with peninsulas is that they often overlap each other. There can be a number of levels of peninsulas on one patch of coastline. See the following image:
That's why I propose tags that have a key with a number, like peninsula:1 or peninsula:4. So for the example in the image we would have:
Which number should I use if I just want to tag a small peninsula? It should be high enough so that all other peninsulas can get their number. A number that is too high shouldn't be a problem, but a too low number could lead to renaming a whole set of coastlines.
There is one more problem with this tagging, and that is in case a peninsula stretches through several countries. Then the peninsula has several names, and data consumers couldn't figure out if neighboring peninsula:0=Peninsula of Europe and peninsula:0=Poluotok Europa are the same or two distinct peninsulas. That's why we should always use language extensions and have peninsula:0:en=Peninsula of Europe, and that would stretch throughout the whole peninsula.
peninsula:X:wikidata=* A good practice would be to use the wikidata tag because that would unify a peninsula better than other tags. A name of a peninsula can be different even in the same language, if there's different names for it in different parts of a country. Also, a wikipedia tag can differ because they don't have to be in the same language.
Why not relation?
Relations are in a way a better way of mapping a peninsula, with one object per feature rule. Also, it removes the need for somewhat clumsy peninsula:X tagging. But the problem is obviously too much members in a relation for big peninsulas. There are other problems, but this one makes relations simply unusable for this purpose.
Why not node?
Nodes can't show the exact borders of a peninsula.
Rendering should be the same as for all big geographical features, a big font over the whole peninsula, being slightly curved.
Comments are welcome in the Discussion part of the page.