Addresses

Cognised existence: An address is a structured spatial identifier that connects a human activity — dwelling, business, service — to a point in geographic space. It is a universal join key in many geospatial data ecosystems.

Question: Where is a property located by its official address?

What is an Address?

An address is not a coordinate. It is a layered set of identifiers (street name, house number, floor, door) that can collapse to one or more coordinate representations depending on purpose. In most data ecosystems, many registries reference addresses. Understanding the join chain from address entities to geometry is fundamental.

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Realisations

1. DanmarksAdresser (DAR)

The authoritative realisation. DAR is the national address register.

Spatial Access Path

adresse (dwelling: floor + door)
  │  FK: adresseHarHusnummer (1..1)
  ▼
husnummer (building entrance level: "12A")
  │
  ├──► adgangspunkt (1..1)  → entrance point in terrain plane
  │       └─ position: GM_Point (ETRS89/UTM32N)
  │       └─ Use: "where is this building?" — geocoding, proximity analysis
  │
  └──► vejpunkt (1..1)      → road centreline point
          └─ position: GM_Point (ETRS89/UTM32N)
          └─ Use: network analysis, routing, snapping to road graph

3 levels of joins, 2 alternative coordinate points:

Level	Entity	Role	Cardinality
1	adresse	Dwelling-level address (etage + dør)	—
2	husnummer	Building entrance (house number on a named road)	1..1 per adresse
3a	adgangspunkt	Entrance coordinate (terrain plane)	1..1 per husnummer
3b	vejpunkt	Road centreline coordinate (for network analysis)	1..1 per husnummer

Both adgangspunkt and vejpunkt are instances of the Adressepunkt superclass, stored in the adressepunkter table. Each carries:

• position — the GM_Point geometry
• oprindelse — provenance and quality metadata (source, accuracy class, technical standard)

Supporting Entities

Entity	Role	Join
navngivenvej	Street name	husnummer → navngivenVej (0..1)
postnummer	Postal code area	husnummer → postnummer (1..1)
supplerendebynavn	Supplementary city name	husnummer → supplerendebynavn (0..1)

Key Attributes

Attribute	On	Description
adressebetegnelse	adresse	Full formatted address text
husnummertekst	husnummer	House number including letter suffix (“12A”)
etage	adresse	Floor number
doer	adresse	Door identifier (“tv”, “th”, “mf”, or number)
postnr	postnummer	4-digit postal code
postnrnavn	postnummer	Postal district name

Access

• GraphQL: adresse with joins to husnummer, adgangspunkt, vejpunkt
• File Download: Bulk exports of all DAR entities
• DAWA: Free API at https://api.dataforsyningen.dk/adresser

2. OpenStreetMap

Secondary realisation. OSM stores addresses as addr:* tags on nodes and building polygons.

OSM Tag	DAR Equivalent
addr:street	navngivenvej.vejnavn
addr:housenumber	husnummer.husnummertekst
addr:postcode	postnummer.postnr
addr:city	postnummer.postnrnavn

Spatial access: Direct — the node/polygon itself carries the geometry. No join chain needed. But OSM addresses lack the dwelling-level precision (no floor/door) and have no authoritative provenance.

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Classical Theme References

Standard	Theme	Link
ISO 19115	Location	|Location
INSPIRE	Addresses	|Addresses
UN-GGIM	Addresses	|Addresses

Temporal Model

Bitemporal (from Shared Temporal Superclass Contract). Address lifecycle: created → active → retired. Historical queries on virkningFra/virkningTil.

Realised By Links

• DanmarksAdresser (collection)
• Bygninger og boliger (collection)

Unmatched Realisations

• OpenStreetMap

Realised By Links

• DanmarksAdresser (collection)
• Bygninger og boliger (collection)

Unmatched Realisations

• OpenStreetMap