Proposed features/Mapping disputed boundaries

From OpenStreetMap Wiki
Jump to: navigation, search


The purpose of this proposal is to advance the implementation of the Policy on Disputed Territories of the OSM Foundation, as implemented and enforced by its Data Working Group (referred to collectively in this proposal as the OSM Institutions), and in particular the policy's Summary Point 4, which states in part:

We recognise the importance of names, borders and descriptions to different national, ethnic, culture or language groups. We have and will continue to build mechanisms where alternatives can be recorded and easily used in maps.

Basic approach and scope

This proposal is intended principally to address disputed borders at the national level, meaning frontiers tagged with admin_level=2. In its simplest form, it considers the world as divided up into areas covered by boundary relations, each of which is normally controlled by zero or one country (or "claiming entity"). Rarely, a boundary relation area will be jointly controlled by the claiming entities.

This proposal covers certain boundary relations and their members. The scope expressly excludes historical and potential future claims, and includes only current, verifiable, official claims by a claiming entity. The goal is to establish boundary relations to enable producing alternative maps.

Possible extensions include boundaries at the subnational level (with admin_level=3 to admin_level=11) and third-party views of claims.


You can skip down to the section How to Map.

Tags and definitions


Claiming Entity: a member of the List of Claiming Entities. The term resolves the meaning of "country" as it applies to borders with admin_level=2. It supersedes the existing recommendation that "only political entities listed on the ISO 3166 standard are to be considered countries." Any time the term "country" or "national" is used in this proposal, it should be considered as shorthand for "claiming entity".

Country Code: a code representing a Claiming Entity. Use the two-letter code from ISO 3166 if it exists; otherwise use the four-letter code in the List of Claiming Entities.

Administrative boundary relation: a country's Administrative boundary relation is the one currently tagged boundary=administrative + admin_level=2.

boundary segment: a way that forms part of a boundary.

Master Claim: This proposal creates a new boundary relation at the country level, with type=boundary + boundary=master. This relation, the Master Claim, comprises the territory (land and maritime) claimed by the country; this is the country's view of itself. Note: if the country has no territorial claims outside its administrative boundary, and nobody has claims on the country's territory, do not create the (unnecessary) Master Claim.

Boundary Claim relation: This proposal creates a new boundary relation, with type=boundary + boundary=claim. Any territory disputed between two or more Claiming Entities is described either by an administrative boundary relation or by a Boundary Claim relation. Boundary Claim relations can also describe Terra nullius or any area controlled by more than one Claiming Entity jointly under mutual agreement (see Special Cases, below).

Conflict Area: This proposal creates a new boundary relation, with type=boundary + boundary=conflict_area. Such an area, comprising two more boundary relation areas, represents overlapping disputed (i.e., non-cooperative) claims of Claiming Entities. Conflict Area relations are optional.

The Master Claim

Members of the Master Claim will normally include:

  • role:admin_centre -- administrative centre(s)
  • role:undisputed, role:joint, role:de_facto, or role:claimed -- boundary relations claimed by the country
  • role:outer -- outer border segments
  • role:inner -- inner border segments (for enclaves)

Tags are generally copied from the corresponding administrative relation with some exceptions:

  • the value of the boundary=* tag on the relation is changed from administrative to master
  • the admin_level=* tag is removed
  • a country_code=* tag is added

Newly defined tags

See below for examples.

  • boundary=claim -- on a boundary claim segment that does not qualify as boundary=administrative
  • claimed_by=* (one or more country codes, or nobody) -- on a boundary relation
  • claim_level=* -- on a Boundary Claim relation where all claimants agree on the claim level
    • claim_level:claimant_country_code=* -- on a boundary relation where the claimants assign different claim levels. Note: this tag can apply to either an Administrative boundary relation or a Boundary Claim relation.
  • controlled_by=* (nobody, UN, or one or more country codes) -- on a boundary relation. Note: UN indicates that a United Nations mission is exclusively or jointly administering the area, such as a buffer area under the aegis of a UN peacekeeping mission.
  • boundary=conflict_area -- on an optional Conflict Area relation
  • country_code=* -- on a Master Claim to indicate the country code
  • boundary=master -- on a Master Claim
  • boundary=claim -- on a Boundary Claim relation

Newly defined roles with the Master Claim

  • undisputed -- for an undisputed boundary relation area. That is, the Claiming Entity claims this area, and nobody disputes it.
  • joint -- for a boundary relation that the Claiming Entity controls cooperatively with another Claiming Entity.
  • de_facto -- for a de facto but disputed boundary relation. For a Master Claim, the Claiming Entity controls this area, but it is also claimed by someone else. Note: this role is also used for Conflict Areas, which have no Claiming Entity, for a de facto but disputed boundary relation.
  • claimed -- for a boundary relation that the Claiming Entity claims but does not control. This area is under the control of a different claimant, or nobody.

New list

One new official OSM list is created, derived from the criteria in the proposal:

Existing tags

The proposal makes reference to these existing tags:

Details of proposal

Claiming entity

Claiming entities are those entities, usually national governments, that meet certain criteria to be eligible to register claimed borders. The criteria for the List of Claiming Entities are important to this proposal.

The proposal supports the Policy on Disputed Territories by specifying objective criteria to flesh out the current subjective standards. The following criteria for the list match the current application of the policy and are a part of this proposal:

  • Any full member of the United Nations General Assembly
  • Any entity that exercises control over territory AND that is recognised by at least 10 full members of the United Nations General Assembly.

The criteria are crucial to applying the policy. See the discussion page.

Changing the criteria

Anyone wishing to change the criteria for the List of Claiming Entities should follow the Proposal process. In addition to the rationale and other relevant sections of the process, these specific points should be included:

  • Change in criteria: The proposal should detail the new and old criteria.
  • Change in list: The proposal should specify which Claiming Entities will be added to the list, or removed from it. For any entity being added to the list, the proposal must provide a four-letter Country Code.

Administrative boundary relations

The administrative boundary is the one that conforms to the Policy's statement: "Currently, we record one set that, in OpenStreetMap contributor opinion, is most widely internationally recognised and best meets realities on the ground, generally meaning physical control." It is represented by the Administrative boundary relation, and should be tagged as is done currently:

type=boundary + boundary=administrative + admin_level=2

Segments should be tagged:

boundary=administrative + admin_level=2

Boundary claim relations

The members of a boundary claim relation are boundary segments, which must be tagged either boundary=administrative (if they are part of an administrative relationship) or boundary=claim (if they are not). They receive the standard outer or inner role within the relation.

The relation is tagged as follows:

type=boundary + boundary=claim

If the claimants agree on the claim_level, add a tag:

If they disagree, show the viewpoint of each claimant:

If all tags on two boundary claim relations are identical, they should normally be merged into a multipolygon.

Boundary relation tags

The following tags apply to all Boundary Claim relations and Administrative boundary relations.

claimed_by=* (either one or more country codes, or nobody)

controlled_by=* (one or more country codes and/or UN, or nobody)


  • For the claimed_by tag, use as many country codes as there are claimants, separated by semicolons. It is probably best to put the country codes in alphabetical order. If there are no claimants, use the keyword nobody.
  • For the controlled_by tag, the keyword UN can be used as a "country code", and the keyword nobody can be used instead of the list of country codes.
  • Use claim_level=2 if the claimant considers the area integral to its country (i.e., the claimant would draw its national border to include the boundary relation but would not draw an internal border to demarcate it). Use higher numbers if the claimant considers the area to be integral but at a less important point in the government hierarchy (typically 3 or 4 for a province or region).


  • claimed_by=KOSO;SR -- boundary relation's area is claimed by Kosovo and Serbia
  • claim_level:SR=4 -- Serbia considers this boundary relation's area to be at level 4 (province)
  • claim_level:KOSO=2 -- Kosovo considers this boundary relation's area to be at level 2 (country)
  • claimed_by=RU;UA -- area is claimed by Russia and Ukraine
  • claim_level=4 -- All claimants consider this boundary relation's area to be at level 4 (province)

Conflict areas

Conflict Area relations are optional under this proposal. They can be especially useful if the area is prominent, like Western Sahara, because otherwise there would be no relation with well-defined tags on OSM to describe the conflict. They should be tagged as follows:

type=boundary + boundary=conflict_area

The administrative or boundary claim relations comprising the Conflict Area should be added as members with the role de_facto.

The boundary segments defining the area should be added as members with the appropriate role: outer (normal) or inner (for enclaves).

Special case: Uncontrolled territory

There will on occasion be a area where no claiming entity exercises continuous exclusive control. A typical example of this would be an uninhabited disputed island, such as Parsley Island in the Mediterranean Sea. This island is claimed by both Spain and Morocco. After a military skirmish between the two, they agreed that neither would occupy the island. The tagging is:

type=boundary + boundary=claim + claimed_by=ES;MA + controlled_by=nobody

A determination about which claiming entity, if any, exercises control over a particular territory can be made by the Data Working Group if consensus cannot be reached.

Special case: Cooperative jurisdictions

In contrast to unclaimed territory, there are some boundary relations where the claiming entities jointly exercise effective control by mutual agreement. Nothing in this proposal prohibits such overlaps.

An example of this is the Germany-Luxembourg condominium. The tagging for the boundary relation is:

type=boundary + boundary=administrative + claimed_by=DE;LU + controlled_by=DE;LU

Special case: Terra nullius

There are a few parts of the world claimed by nobody. Most of these are islet outcroppings. There are two significant areas of such terra nullius: most of Antarctica, and Bir Tawil.

Terra nullius areas are tagged as follows:

type=boundary + boundary=administrative + claimed_by=nobody + controlled_by=* (country code(s) and/or UN, or nobody)

Even though the land is unclaimed, it is possible to be controlled by a Claiming Entity. For instance, Bir Tawil, though not claimed by Egypt, is effectively controlled by it.

Special case: Administered territory

Sometimes an entity controls territory but does not claim it, such as a buffer strip controlled by a UN peacekeeping force. For the case where nobody claims it, see Terra nullius, above. If the territory is claimed, tag it:

type=boundary + boundary=claim + claimed_by=* (one or more country codes) + controlled_by=* (country code(s) and/or UN)

Administered territories are added to the Master Claim of any country that claims the territory (role: claimed), but not to the Master Claim of any administrator.

Step by step

As an example, consider the dispute between Morocco (MA) and Sahrawi Arab Democratic Republic (SADR) over Western Sahara. MA controls those parts of Western Sahara that are north and west of the Berm. SADR controls those parts of Western Sahara south and east of the Berm.

The overlap of the claims of MA and SADR exactly matches the boundary of Western Sahara, a Conflict Area. The Berm divides Western Sahara into five areas. One is controlled by MA and becomes a boundary claim relation; the rest are controlled by SADR and are merged into one multipolygon boundary claim relation. Each boundary relation gets an appropriate tag:

  • controlled_by=* (either MA or SADR in this case)
  • claimed_by=MA;SADR
  • claim_level=2

The administrative boundary for MA remains the same. It is contiguous with its boundary claim relation in Western Sahara plus its administrative boundary relation to the north. The administrative boundary for SADR also remains the same. It is equal to its boundary claim in Western Sahara.

The Master Claim for MA includes all of Western Sahara, as well as its claims to the north. The Master Claim for SADR includes all of Western Sahara.

Tags for some real-world disputes

  • China: mainland China would be an administrative boundary, controlled_by=CN + claimed_by=CN;TW. Taiwan would be another administrative boundary, controlled_by=TW + claimed_by=CN;TW.
  • Crimea: To conform to the currently approved de facto borders, the administrative boundary relation, which comprises all of Crimea, would be tagged type=boundary + boundary=administrative + admin_level=2 + claimed_by=RU;UA + controlled_by=RU;UA + claim_level=4.
  • Israel-Palestine: To conform to the currently approved de facto borders, there would these boundary relations:
    • West Bank, claimed_by=PS + controlled_by=PS.
    • Gaza, claimed_by=PS + controlled_by=PS.
    • Israel, claimed_by=IL + controlled_by=IL.
    • East Jerusalem, claimed_by=IL;PS + controlled_by=IL.
  • Israel-Syria: The Golan Heights would be an administrative boundary relation, claimed_by=IL;SY + controlled_by=IL.
  • Israel-Lebanon: Shebaa Farms would be an administrative boundary relation, claimed_by=IL;LB + controlled_by=IL.
  • Kashmir: There are three administrative boundary relation areas in dispute, with different pairs of claimants. (No area is claimed by all three.)
    • Jammu and Kashmir, controlled_by=IN + claimed_by=IN;PK.
    • Northern Areas, controlled_by=PK + claimed_by=IN;PK.
    • Aksai Chin and Trans-Karakoram Tract, controlled_by=CN + claimed_by=CN;IN.
  • Kosovo: One administrative boundary relation encompasses all of Kosovo; it would be tagged type=boundary + boundary=administrative + admin_level=2 + claimed_by=KOSO;RS + controlled_by=KOSO + claim_level:RS=4 + claim_level:KOSO=2.
  • Transnistria: Under the proposal's criteria, Transnistria is not in the List of Claiming Entities, so Moldova would be considered an undisputed administrative boundary relation (with no competing claim, because Transnistria would not be a Claiming Entity). In such a case, there is no need to create a Master Claim for Moldova, and no need for a boundary claim relation. This matches the current mapping in OSM. Transnistria would appear (as now) as a province with an appropriate admin_level (3 or 4). The Transnitria leaders' claim would not gain credence as a boundary claim. At some future date, if Transnistria is included in the List of Claiming Entities, then Transnistria with respect to Moldova would be treated the same as Kosovo with respect to Serbia.
  • Rebel groups, Islamic State, micronations: Like Transnistria, their claims would not be mapped as boundary claim relations, because they are not on the List of Claiming Entities. (This would not prevent mappers from creating other types of relations under the notion of Any Tags You Like, but they would not qualify for use of the boundary claim relation.) The Description or Note tag can be used as needed to describe the situation.

The world according to country XX

Building a map of the world according to country XX requires a database indicating which claims are accepted by country XX. (To include such a database in the OSM tags, see the possible extensions). In the following algorithms, "boundary relations" refers to relations tagged type=boundary + claimed_by=*.

For each country ZZ, its land area according to country XX is equal to:

 Boundary relations where claimed_by contains ZZ and the database shows that XX sides with ZZ for that area 
 + boundary relations where claimed_by contains ZZ and controlled_by contains ZZ and XX is neutral for that area

The administrative relation for country ZZ is equal to:

 Boundary relations where claimed_by contains ZZ and controlled_by contains ZZ 

The Master Claim for country ZZ is equal to:

 Boundary relations where claimed_by contains ZZ 

Conflict Areas affecting country ZZ and XX can be found as follows:

Boundary relations where claimed_by contains ZZ and claimed_by contains XX

Backward compatibility and transition

See the discussion page.

How to map

Changes in boundary relations and their members can be highly contentious. When in doubt, seek consensus on the appropriate mailing lists. Always follow the criteria established in the Policy on Disputed Territories. Default boundaries should not be changed without a good reason, which should be stated at the time of the change (using the comment feature of the changeset).

Create Boundary Claim relations

Boundary Claim relations should have a solid basis, preferably based on claims from a country's constitution or laws, from an official government agency, or from a reputable source that has summarised the situation. The basis (including links and/or contact information) should be included in the changeset comment.

Tag the boundary relation's claim_level(s). Examples:

Add a tag controlled_by=country_code.

See above for other appropriate tags for boundary relations.

Add the boundary relations to the Master Claim as appropriate, with the role undisputed,joint, de_facto, or claimed.

The existence of a new boundary can affect each Claiming Entity's admin_level=2 boundaries. In addition to any other tags, the boundary between each Claiming Entity and the new boundary should now be tagged boundary=claim if the boundary was not previously tagged as administrative, or boundary=administrative + admin_level=2 if it was. The segments are added to the Boundary Claim relation with the role outer. (As usual, any enclaves would get the role inner.)

Rendering possibilities and live examples

Western Sahara

See the possible renderings page for Western Sahara examples.

  • Morocco administrative relation: its area includes all the territory Morocco controls; it is the same as the current administrative relation.
  • Morocco Master Claim: its area includes all Moroccan claims (Western Sahara, Melilla, Ceuta, Parsley Island, etc.) as well as those parts of the country unclaimed by anyone else.
  • Sahrawi Arab Democratic Republic administrative relation: its area includes all the territory SADR controls; it is the same as the current administrative relation.
  • Sahrawi Arab Democratic Republic Master Claim: its area includes all SADR claims; in other words, it is contiguous with Western Sahara.

Live example

Examples on the development server

Possible extensions

This discussion page on possible extensions offers a scratch pad for thoughts on this topic, such as:

  • Subnational claims
  • Names and descriptions "according to"
  • Viewpoints of third parties on claims

See also

Comments and changelog

Please see the discussion page.

External discussions

Main threads on OSM lists

RFC for this proposal on the Tagging list

RFC for this proposal on the Talk list

Related threads

Add some tag to identify disputed borders

OSMF silently sides with Russia?

OSMF makes a political decision where should be a technical solution?

Slack discussion

On OSM US #borders channel