Need a way of highlighting disputed/contested areas

[jeffreyameyer]

Style change requested

It would be nice if we could call out disputed areas / territories with some sort of transparent overlay to visually signify when there are territorial disputes (without judgement as to the validity of these disputes).

Some currently mapped examples:

• Louisiana Disputed Territory (1803-06)
• Maine Disputed Territory (1783-1842)
• US-Canada Lake Superior border dispute (1783-1842)

Other obvious, but not mapped examples:

• US Revolutionary War
• US Civil War (as states entered the CSA)
• Modern Ukraine

I'm open to whatever suggestions we have for approaching this, but I'm thinking that it doesn't need to be apparent for too deep of a zoom, or that maybe there are different treatments at different zooms - e.g.:

• browser zoom 4-8 = transparent area highlight
• browser zoom 9-12 = some sort of transparent pattern (diagonal lines?)
• browser zoom 2-3, 13-20 = nothing

Affected Tag or Tags

Right now, I've been tagging these with some variety of:

disputed=yes

or

territory=disputed
territory:claimant:#=claimant name

cc: @1ec5

[1ec5]

I think typically maps that depict boundaries as solid lines use dashed lines to indicate disputes. But the Historic style is already using dashed lines for subnational boundaries. Placing a casing around the boundary, as it common in atlas-style maps, opens up some additional possibilities. For example, in ZeLonewolf/openstreetmap-americana#211, disputed boundaries disappear over water (convenient for that map, but maybe undesirable for this one) and become just the casing over land.

As far as tagging, OpenStreetMap has more or less settled on disputed_by, claimed_by, and to some extent recognized_by, but the values are still up in the air. The proposal was limited to countries with ISO 3166-1 country codes, so it didn’t consider subnational disputes and obviously didn’t consider disputes between historical entities. I’ve been quietly bucking that consensus around country codes by mapping disputes between a city’s neighborhood councils.

OSM data consumers such as OpenMapTiles use these tags to filter boundaries according to an American worldview, Chinese worldview, etc. Is there a view towards doing something similar with OpenHistoricalMap, or is the intention more to display the parties’ names to the user? If the latter, then maybe integration with Wikidata would be less messy in the long run. We should ensure that every disputed territory is linked to a Wikidata item specifically about that dispute and not about tangential topics, as in some of the examples above. Then we could rely on Wikidata statements like territory claimed by (P1336), item disputed by (P7378), statement supported by (P3680), and statement disputed by (P1310) to come up with the list of parties pretty straightforwardly in the inspector.

[jeffreyameyer]

Should we turn over to @vknoppkewetzel & @tsinn for carto options?

[jeffreyameyer]

Posted on #204 a question of whether this should be merged with that ticket or linked somehow.

Separately, the question of how we map / depict speculative and uncertain boundaries has been raised a bit more frequently. Notably, by the head of the California Map Society, who is already an advocate for OHM, but who could be an even bigger advocate if we actively engage on this topic.

To that end, I've created a forum topic where we might discuss different visual treatments and barriers to implementing them. It's also a place to discuss and resolve the tagging concerns outlined by @1ec5 above.