City plans that were approved and came into force in 2016–2019 are a geographic dataset containing areal geometries. The data contains the delimitations of those city plans that indicate residential floor area.
HSY has collected the data from the municipalities of the Helsinki region (Espoo, Helsinki, Kauniainen, Vantaa, Hyvinkää, Järvenpää, Kerava, Kirkkonummi, Mäntsälä, Nurmijärvi, Pornainen, Sipoo, Tuusula and Vihti) in the spring of 2017–2019 as part of the follow-up of the Helsinki region MAL agreement.
Interface address: https://kartta.hsy.fi/geoserver/wfs
Instructions for using the WFS interface (in Finnish): https://kartta.hel.fi/avoindata/dokumentit/Ohje_WFS_haku_ulkoverkko.pdf