The BAG

The BAG (Basisregistratie Adressen en Gebouwen) is the Dutch national register of addresses and buildings. Gemeenten maintain it, and Kadaster distributes it. Every month PDOK publishes the full register as one extract: a ZIP of ZIPs holding about 105 GiB of XML. Kadaster’s download page links to the latest one; a new extract appears on the 8th of each month.

bagkit uses the BAG’s own terms, as the extract and Kadaster’s BAG API use them: in table and column names, in the HTTP API, and in this documentation. The glossary defines each one.

Object types

BAG	In English	What it is
Woonplaats	Locality	A named place, designated by a gemeente
Openbare ruimte	Public space	A named street, water, square or other public area that nummeraanduidingen lie on
Nummeraanduiding	Address	A postcode and huisnummer, with an optional huisletter and huisnummertoevoeging, on an openbare ruimte
Verblijfsobject	Unit	A space inside one or more panden with its own adres, gebruiksdoelen and oppervlakte
Ligplaats	Mooring	A place in water for a houseboat or other permanently moored vessel
Standplaats	Pitch	A place on land for a mobile home or other structure that is not fixed in place
Pand	Building	A permanent structure with its own geometrie

Verblijfsobjecten, ligplaatsen and standplaatsen together are adresseerbare objecten: the things nummeraanduidingen belong to.

How they relate

• A nummeraanduiding lies on one openbare ruimte, and an openbare ruimte lies in one woonplaats.
• A nummeraanduiding can name its own woonplaats, which overrides its openbare ruimte’s. A nummeraanduiding with the names of its openbare ruimte and woonplaats is an adres.
• An adresseerbaar object has exactly one hoofdadres and any number of nevenadressen. The BAG records this on the object; bagkit stores it on the nummeraanduiding: which object it belongs to, and whether it is a nevenadres.
• A verblijfsobject lies in one or more panden, and a pand can hold many verblijfsobjecten.

Gemeenten and provincies

Gemeenten are not part of the BAG. Kadaster ships a separate file with the extract, GEM-WPL-RELATIE, that relates each woonplaats to a gemeentecode. bagkit reads it, and names gemeenten and their provincies from a table built into bagkit, generated from PDOK’s administrative boundaries. After a municipal reorganisation, new codes have no name until that table is regenerated.

Voorkomens and history

The extract holds every version of every object. Each version is a voorkomen with a validity period. bagkit keeps only the voorkomens that are current on a peildatum.

Two kinds of voorkomens never count as current:

• Inactief: versions the BAG later replaced with a correction, so they never described their object.
• Niet-BAG: objects that were taken out of the BAG.

Statuses

Every object has a status, such as Verblijfsobject in gebruik or Naamgeving ingetrokken. bagkit keeps statuses and other code-list values as the BAG records them. A nummeraanduiding with status Naamgeving ingetrokken is ingetrokken: it stays in the nummeraanduidingen table, but searches and the adreslijst leave it out.

Coordinates

The BAG records geometrie in RD New (Rijksdriehoeksstelsel, EPSG:28992), the Dutch national grid in metres. bagkit keeps geometrie in RD New and adds a WGS84 breedtegraad and lengtegraad for every adresseerbaar object’s punt.