Base map of the City of Helsinki

The base map of Helsinki is a large-scale (1:500) map maintained by the Urban Environment Division’s City Survey Services and used as a basis for city planning and civil engineering. The base map serves as a map template for the detailed plan and is also used for the production of many special maps. The base map is the most accurate geographic dataset depicting the area of the City of Helsinki. It is kept constantly up to date at a scale of 1:500.

The dataset has been produced through aerial photography, terrain measurements and property deliveries, as well as building permit processing measures. The base map meets the quality requirements of the base map of the plan maintained by the municipalities (previously the public office map). The documentation technique of the base map is defined in the publication of the National Land Survey of Finland No 94 Kaavoitusmittausohjeet 2003. The base map is used to produce the statutory map templates for detailed planning.

Coordinate systems:

  • Maintained in ETRS-GK25 (EPSG:3879), can be projected to other coordinate systems. See GetCapabilities query for other possible coordinate systems.

Vertical coordinate reference system:

  • N2000.

API addresses:


  • Kantakartta (also WMTS API)
  • Kantakartta_harmaa (greyscale)
  • Kantakartta_valkoinen (white)
  • Kantakartta_rajat (boundaries)
  • Kantakartan_maastotiedot (also WMTS API)
  • Kantakartta_pohja
  • Kantakartta_paakohteet (main features)
  • Karttasarja
  • Karttasarja_harmaa (greyscale)


Additional Info

Collection Open Data
Maintainer Helsingin kaupunkiympäristön toimiala
Maintainer email
Maintainer website
Links to additional information
Geographical coverage
Update frequency
Last modified 18.10.2022
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Created on 14.08.2017