OpenHistoricalMap/Projects/Denmark

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OHM Denmark in 1905

Administrative divisions

Proposal for mapping boundaries:

  • Map internal boundaries (Amt, Kommune, Herred, ...) using boundary lines that closely follow the coast, about 100-200 m distance from the coastline. This reduces the need for excessive revisions to the divisions with minor changes to the coastline.
  • Map modern international boundaries using the published coordinates:
    • In 1999, Denmark adopted territorial sea boundaries based on 12 nautical mile limit (wikipedia:UNCLOS)
    • In 1966, Denmark adopted territorial sea boundaries based on 3 nautical mile limit defined by coordinates (baseline) in "AND nr 437 af 21/12/1966".
  • Map earlier international boundaries using available sources (maps/nautical charts). If no sources are available, assume a 3 nautical mile territorial sea.

Comparison to OpenStreetMap

See also Denmark/Da:Administrative_boundaries.

In OSM, administrative boundaries of regions and municipalities in Denmark do not include territorial waters (towards the sea) but also don't include many internal waters (bays, fjords). Lakes and rivers are generally included. These boundaries are made up of coastline segments. The boundary relations at the country level in OSM include territorial waters based on current international agreements (since 1999 generally 12 nautical miles off the coast except where other agreements exist).

Boundaries in OHM can follow a similar approach, where lower administrative units (Region, Amt, Kommune, Herred, etc.) use coastline, and country boundaries include whatever territorial waters are claimed at the time. In practice, this could cause boundary relations to get very large since every island and islet needs to be included as a separate boundary member. It also means that administrative boundaries need a new boundary relation whenever the coastline changes anywhere in the administrative division, which would happen every time land is reclaimed, a harbor is expanded, etc. A more practical approach could be to offset the boundary slightly from the coast, about 100-200 m.

More discussion: https://forum.openhistoricalmap.org/t/how-should-we-handle-territorial-waters-or-should-we-include-shorelines-in-boundaries/154

Country/Kingdom/Realm

Denmark (proper) vs Kingdom of Denmark

OSM currently has Kingdom of Denmark (relation 9112011) as a boundary relation that contains Denmark (proper), Faroe Islands and Greenland. This is a boundary=administrative without any admin_level=* tag. The only equivalent in OHM is currently Danish Realm (https://www.openhistoricalmap.org/relation/2849655 ) (1944-). This should be extended further back in time and included in a chronology for Kingdom of Denmark. The WikiData entry for Kingdom of Denmark/Danish Realm is wikidata:Q756617.

The OSM relation for Denmark (proper) is relation 50046. This is a boundary=administrative with admin_level=2. The WikiData entry for Denmark (proper) is wikidata:Q35.

OHM currently has a chronology for Denmark (https://www.openhistoricalmap.org/relation/2801214 ) though the tagging does not clearly disambiguate between Denmark proper and Kingdom of Denmark. All of the contained boundaries in this chronology include areas outside of Denmark proper.

To Do:

  • When did the distinction between Denmark proper and Kingdom of Denmark first appear? (i.e. when should a chronology for Denmark (proper) start and when should a chronology for Kingdom of Denmark start?)
  • Create separate chronologies and clean up the membership so boundaries for the kingdom are in one chronology and boundaries for Denmark proper are in the other chronology
  • Clean up the country boundaries that are currently intersecting the coastline in many places and convert them to maritime boundaries that are offset from the coast

Sources

Amter (Counties; 1662-2007)

Use boundary=administrative with admin_level=4. Potentially these could use level 5 instead since they smaller than the regions (which are mapped in OSM at level 4) but currently level 4 is used.

Note that counties have not been static through this period.

Regioner (Regions; 2007-)

Use boundary=administrative with admin_level=4 as in OSM. (See Tag:boundary=administrative#admin_level)

These divisions were created by wikipedia:da:Strukturreformen in 2007.

Kommuner (Municipalities)

Use boundary=administrative with admin_level=7 as in OSM. (See Tag:boundary=administrative#admin_level)

These divisions seem to have come into existence roughly around 1800 and gradually gained importance. In 1970, a major reorganization of the municipalities happened with wikipedia:da:Kommunalreformen_(1970).

Herreder (wikipedia:Hundred (county division))

Use boundary=administrative with admin_level=6. According to wikipedia:da:Herreder_i_Danmark#Afvikling, this administrative division gradually lost importance starting from 1919 ("Retsplejeloven af 1916" entering into force in 1919) so 1919 might be a good end date for these boundaries. Many of these divisions are mentioned in wikipedia:da:Kong_Valdemars_Jordebog, meaning they must have existed around 1200-1300.

Example:

  • Lynge-Kronborg Herred (Frederiksborg Amt): https://www.openhistoricalmap.org/relation/2856326

Sogne (Parishes)

Could be mapped with boundary=religious_administration with admin_level=10

Other divisions

Sources

Other Resources

Trap

J.P. Trap. Statistisk Topografisk Beskrivelse af Kongeriget Danmark (see also wikipedia:da:Wikipedia:WikiProjekt_Trap_Danmark)

Cities

Railroads

See Railways and Railway_stations for details on mapping stations.

Infrastructure

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