Publieke Dienstverlening Op de Kaart

About services

Below is an overview of the various protocols supported by PDOK.

The protocol largely depends on the underlying data set as demonstrated by the overview of URLs. PDOK adopts tiling services (and not the WMS protocol) for popular dat sets. The Open Geospatial Consortium (OGC) standards are used to the maximum extent possible. Tiling services are more efficient than the WMS protocol. With WMS the map is recreated everytime and this is a heavy burden on the PDOK servers. With tiling services images are pre-stored and these images are ready for loading from the cache at all times.

Overview service protocols with PDOK
Abbreviation Description Type OGC
WMS

Web Map Service

Raster data (images)

Yes

WMTS

Web Map Tile Service

Raster data (images)

Yes

TMS

Tile Map Service

Raster data (images)

"Older but effective"

WFS

Web Feature Service

Vector data (lines, points, etc.)

Yes

OpenLS

BAG Geocoding Service

Addresses and Locations

Yes

WCS

Web Coverage Service

Coverage

Yes

The BAG Geocoding service determines a location (not a map) based on an address. This service is therfore a special type of service. An example use might be: Search the location of de Grote Markt in Groningen:

http://geodata.nationaalgeoregister.nl/geocoder/Geocoder?zoekterm=grote+markt+groningen

PDOK presents the location with a (X,Y) co-ordinate in the Dutch Rijks Driehoek Stelsel (RDS) projection. For all PDOK services, the standard map projection is EPSG Projection 28992 (RD new).

With respect to Tile Map Services (TMS), one can say that TMS is slightly simpler than the Open Geospatial Consortium (OGC) recommended WMTS protocol. For this reason, PDOK is serving the Basis Registratie Topografie (BRT) maps via both the WMTS and the TMS protocol.