WFS API

From the dataset abstract

The dataset includes the land and water areas of Helsinki as geographic data features in the form of areas. Bridges and small piers have been removed from the land areas and added to the water mask. Large piers are classified as land areas: a pier is counted as a land area when it is surrounded by a retaining wall. In that case, the coastline goes around the pier. Smaller water bodies have not been dealt with so far, and for them, the water mask is not consistent.

The dataset is automatically compiled from the data of the cadastral map and base map. The dataset is experimental, so small formation errors are possible. The dataset is also available with the official regional divisions (city districts, district divisions, excluding small districts), which can be used, for example, to present statistics. Generalised land data has been used in the division (small islands and water bodies have been removed from the dataset). In addition, the interface service includes layers for just the land in each area (it is advisable to use this with a simplified water mask from the land and water base data).

The data is divided into the following layers:

• manneralue (sis. kaikki vesialueet): mainland (including all waters)
• maa-alue yleistetty (vain suurimmat vesialueet ja alle 500m^2 saaret poistettu): land area generalised (only the largest waters and islands smaller than 500m^2 removed)
• merialue: sea area
• saaret: islands
• muu_vesisto: other_water_body
• vesialue yleistetty (merialue ja suurimmat muut vesialueet; sisältää saaret, jotka yli 500m^2): water area generalised (sea area and largest other water areas; includes islands larger than 500m^2)

The data is available for download in several formats, including JSON, KML, GIF, Tiff, GeoTiff, JPEG, PNG, CSV, Esri Shape. Available formats can always be found under OutputFormat in the GetCapabilities query for the service.

NOTE: The datasets are heavy in geometrical properties, and their WFS download in GML format for older QGIS versions may take time or be interrupted depending on the speed of the internet connection, etc. It is faster to use the data directly in file format downloaded from the interface. For example, all regional divisions from the interface as shapes. There should be no problems with the WMS download.

Previewing the data in the kartta.hel.fi service:

• Sea area
• Water

Coordinate systems:

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

API addresses:

• WFS API: https://kartta.hel.fi/ws/geoserver/avoindata/wfs
• WMS API: https://kartta.hel.fi/ws/geoserver/avoindata/wms

WFS-layers:

• Maavesi_kaikki_aluejaot
• Maavesi_kaupunginosat
• Maavesi_maa_alueet_yleistetty
• Maavesi_manner
• Maavesi_merialue
• Maavesi_muut_vesialueet
• Maavesi_osa_alueet
• Maavesi_peruspiirit
• Maavesi_saaret
• Maavesi_suurpiirit
• Maavesi_vesialue_yleistetty

WMS layers:

• Maavesi_maa_alueet_yleistetty
• Maavesi_manner
• Maavesi_merialue
• Maavesi_muut_vesialueet
• Maavesi_saaret
• Maavesi_vesialue_yleistetty
• Maavesi_alueet
• Maavesi_alueet_yleistetty

Attributes for all layers beginning with Maavesi

• tietopalvelu_id (int): Dataset ID. Reliable, comprehensively existing information.
• tyyppi (string): In the basic dataset: type of area, for example sea or mainland. With regional divisions: land or water area.
• aluejako (string): Type of regional division (regional division layers only).
• tunnus (string): Identifier of the regional division (regional division layers only).
• nimi_fi (string): Name of the regional division in Finnish (regional division layers only).
• nimi_se (string): Name of the regional division in Swedish (regional division layers only).
• pa (float): Area. Process calculated data, not official area (regional division layers only).
• datanomistaja (string): Owner of the data.
• paivitetty_tietopalveluun (date): Information service record date (yyyy-mm-dd).
• geom (geometry): Geometry of the feature.

Administrator: City of Helsinki, Urban environment division, Service and permits, City survey services

Source: Helsingin maa- ja vesialueet