Helsinki, building by building

koodarikettu.github.io/helsinki-by-building

Every building in Helsinki, 85,000 of them, coloured by the year it was completed. What the map shows:

• Colourings. By the period a building was completed, by its floors, by its energy label, by how much solar power its roof could give, or by the heat source the building register records for it.
• Back in time. The timeline plays the city's growth. Go back and the 4,800 buildings demolished since 2008 stand again, paler; the Torn down view shows them all at once in the colour of their age. The city's old maps (1749 to today), with the City Archives', the National Library's and Wikimedia Commons' that fill their gaps, and aerial photos (1932–2025) can lie under the buildings, or be seen alone with the buildings hidden.
• What Helsinki was meant to become. The city's master plans and their proposals from 1923 to 2016 and a competition entry of 1902 for Töölö on the ground, and its road traffic noise as surveyed in 2012, 2017 and 2022.
• Context layers. The protection the city's plans give a building, the protection the state gives it by law, decree or agreement, the national heritage areas (RKY) it stands in, the buildings in Wikipedia, and who lived here: the homes of well-known people whose Finnish Wikipedia article names their Helsinki address, each with the sentence it says so in.
• The building's card. Use, height, floors, structure and facade, architect and style, the Wikipedia extract, the City Museum's photos of it through the years, its energy label and solar potential, and why its street is so named.
• Aerial 3D. The city's photogrammetric 3D model from its 2017 or 2024 aerial photos, in the same scene, from the Map menu.
• Street names. The streets laid on the ground and the buildings faded: streets that once had another name are blue, and a click on one gives its former names and the history they were read from.
• War. A view of each world war. The first: the land front Russia built around the city in 1914–1918, trench by trench as the city surveyed it in 1996, and the damage of the capture of Helsinki in 1918 in the City Museum's photos. The second: the anti-aircraft batteries, the bomb damage of 1939–1944 and the Defence Forces' own photos of the city at war (SA-kuva) at the places they name. For both, the defences in Museovirasto's register and the memorials, each site with a card.
• Other. The city's 475 works of public art, coloured by period; the tram network of the timeline's year, and its railways and metro with their stations, with the tracks closed before it in grey; the Finnish Heritage Agency's and the Helsinki City Museum's photos of Helsinki at the places they name; the veterans' blocks of flats (rintamamieskerrostalot) that the city's municipal reports of the 1950s name, and the terraced houses on Lauttasaari's veterans' plots; and the parking fines of 2014–2023, street by street and year by year, with their commonest reasons.
• Quests. Find buildings from riddles and old photos, and guess their age with the colours switched off.

A non-commercial project, made for curiosity and learning. It is a fork of Alexander Barakov's Amsterdam, building by building (MIT), which was inspired by Sasha Bogachev's Paris, building by building; the architecture, a data pipeline feeding a three.js city, follows theirs. The viewer in web/ is Amsterdam's, with Helsinki's data, Finnish and English.

Floors, in seven steps	War: the land front of 1914–1918	War: bomb damage of 1944

Other: the tram network of 1952	Other: the Heritage Agency's photos of Senate Square	Other: public art

Map: the master plan proposal of 1960	Map: road traffic noise in 2022	Map: the city of 1909

The building's card: archive photos through the years	Context layer: protected in the local plan	Quests: find the building from an old photo

Aerial 3D: the city's model from its 2024 aerial photos	Back to 2017: Pasila on that year's aerial photo, Tripla still a building site	Street names: the former names of Pohjoisesplanadi

Energy labels	Solar potential of the roofs

Screenshots of the map, which uses CC BY 4.0 data © City of Helsinki (buildings, the 3D model and its aerial meshes, aerial photos, old maps, master plans, noise surveys, the land front's survey, street areas and place names) and © HSY (solar potential), the public energy certificates of Varke's register, OpenHistoricalMap's tracks (CC0) and the Helsinki Art Museum's text on Havis Amanda (CC BY 4.0). They show photos by C.A. Hårdh and Jukka Kuusisto (Helsinki City Museum, public domain), by Atelier Aino (Finnish Heritage Agency, Historian kuvakokoelma, CC BY 4.0) and, in the quest, Kaivohuone today by Marit Henriksson (CC BY-SA 4.0).

How it works

open data ──► pipeline/ (Python, uv) ──► web/data/ (binary tiles + JSON) ──► web/ (three.js, no build step)

Step	What it does
s00_fetch	Downloads the City of Helsinki's WFS layers (buildings, land and water, protected buildings, street areas, address points, place names, the land front of 1914–1918, parking fines), roof heights and demolished buildings from its 3D city model, Museovirasto's RKY areas, protected buildings and register of ancient and historic remains (and its page for each defence site), HSY's solar potential, OpenHistoricalMap's tram, rail and metro tracks, the public energy certificates, Wikidata's buildings and stations, the City Museum's, the Heritage Agency's and SA-kuva's photos in Finna, the city's public art and the City Museum's building inventories
s01_load	Buildings, standing and demolished → data/buildings.parquet, one row per building, keyed by VTJ-PRT (or the city's or the model's feature id)
s02_attributes	Completion years (placeholders, rounded decades, missing years), floors, heights
s03_tiles	Packs 600 m tiles into 8 bundles, writes per-building attributes (the heat source among them), addresses and the city config
s04_water	Water and land polygons
s05_layers	Context layers: protected in the local plan, protected by law, decree or agreement, RKY areas, buildings in Wikipedia, who lived here; a bit per group per building
s06_wiki	Names, architects, styles, Wikipedia extracts and Commons photos for buildings with a Wikidata item
s07_labels	Street names placed along their street areas; why each street is so named and its former names; the street areas for the Street names view
s08_archive	Up to six Helsinki City Museum photos per building from Finna, matched by address
s09_quests	Resolves the quests (quests.py) to buildings and checks every claim against its Wikipedia article
s10_energy	Energy labels from the energy certificates and HSY's solar potential, by building
s12_other	The Other menu: public art by period, the tram tracks and the railways and metro through time (trams.bin, rail.bin) with the stations by their opening, the Heritage Agency's and the City Museum's photos by place (; the City Museum's places in , loaded when the view opens), the veterans' blocks of flats and terraced houses and the parking fines by street and year (, loaded when the view opens)

Run it

uv sync
for s in s00_fetch s01_load s02_attributes s13_residents s05_layers s06_wiki s08_archive s09_quests s10_energy s03_tiles s04_water s07_labels s11_war s12_other s14_oldmaps; do uv run python -m pipeline.$s; done
uv run python -m pipeline.test_s02 && uv run python -m pipeline.test_s07 && uv run python -m pipeline.test_s08 && uv run python -m pipeline.test_s10 && uv run python -m pipeline.test_s11 && uv run python -m pipeline.test_s12 && uv run python -m pipeline.test_s13 && uv run python -m pipeline.test_s14   # years, street names, addresses, energy, war, photos and fines, residents, old maps
python3 -m http.server 8642 --directory web

Raw downloads (data/) and generated output (web/data/) are not in the repository: they are rebuilt by the pipeline. The site is web/ with its generated data, less web/data/tiles/ (the packs carry the tiles), on the gh-pages branch, which GitHub Pages serves at the address above. The local frame is metres from Senaatintori (60.1694 N, 24.9527 E) in ETRS-GK25 (EPSG:3879), x east, z south.

Data decisions

• Years. The year is the year of the register's completion date (c_valmpvm), read as written: the dates are local midnights (1968-12-31T00:00:00+02:00), and parsed to UTC they would slip into the year before.
• Rounded decades. Before 1930 the register rounds many dates to the decade: 1900 has 170 buildings against about 33 a year around it, and 1850, 1880 and 1890 run five to ten times over too; from 1930 on the decades match their neighbours. So 1900 is not a placeholder like Amsterdam's 1905 but the oldest dates being approximate. On each round decade before 1930, as many buildings as the years around it predict keep their year; the rest (512 in all, demolished buildings included) are spread across the decade, drawn paler and marked "c." / "n.".
• Missing years. 34,652 buildings have no year and six carry the placeholder 1000 or 1001 (all on one property in Santahamina). Nearly all are sheds, storehouses, outbuildings, garages and summer cottages: buildings with a year hold 99.6% of the floor area. Their year is the median of the dated buildings on the same property (c_kiinteistotunnus, 759 buildings), else of the twelve nearest dated buildings (33,899: most of them are not linked to the register and have no property id). They are drawn paler, marked "c." / "n.", and the card says how the year was found.
• Building types. All 35 types are kept, 84,959 buildings. Räystäs (stereo) (438) looks like a roof edge rather than a building, but its polygons are buildings traced along the eaves in stereo aerial imagery, mostly in Östersundom and Santahamina: 436 of them overlap no other building, 128 are linked to the register (houses, a school, warehouses). Dropping them would remove real buildings.
• Floors and heights. Floors are the register's i_kerrlkm; 34,193 buildings, mostly the same small ones, have none. Heights come from the city's 3D city model (LoD2, served as 3D Tiles), linked by VTJ-PRT: 51,653 buildings. The model's own measuredHeight runs to the highest point, so as a flat block the Olympic Stadium would stand 73 m tall (its tower), the Railway Station 50 m and the Cathedral 59 m. Like Amsterdam's 3D BAG, the map instead takes the 70th percentile of the roof surfaces' height above the building's lowest point, weighted by area: 26 m, 21 m and 36 m; an ordinary block of flats changes little (14.3 m → 13.8 m). The tiles (about 650 MB) are read one by one and only the heights kept. Buildings the model does not link, nearly all small outbuildings, are floors × 3.2 m.
• Use and materials. The card shows the register's use class (c_kayttark, Statistics Finland's Building classification 1994) where there is one, else the base map's building type (tyyppi); the load-bearing material () and the facade material () from Helsinki's own code lists. Sources in .

Licence

Code: MIT (see LICENSE), © Alexander Barakov and contributors. Vendored in web/vendor/: three.js (MIT), 3d-tiles-renderer 0.5.3 (Apache 2.0, web/vendor/3d-tiles-renderer/LICENSE) and the Schibsted Grotesk font, Google Fonts' latin and latin-ext files (SIL Open Font License 1.1, web/vendor/fonts/OFL.txt).

Data keeps the licence of its source:

• Buildings: City of Helsinki, Helsingin rakennukset, WFS layer avoindata:Rakennukset_alue_rekisteritiedot. CC BY 4.0.
• Land and water: City of Helsinki, Helsingin maa- ja vesialueet, WFS layers Maavesi_manner, Maavesi_saaret, Maavesi_merialue, Maavesi_muut_vesialueet. CC BY 4.0.
• Attribution, as the city asks: "Data and maps © City of Helsinki, City Survey Services" ("Data ja kartat (c) Helsingin kaupunki, kaupunkimittauspalvelut"). Downloaded via Helsinki Region Infoshare on 14 October 2026.
• Protected buildings: City of Helsinki, Asemakaavoilla suojellut rakennukset ja alueet Helsingissä, WFS layer Asemakaavoissa_suojellut_rakennukset_alue. CC BY 4.0 (stated on HRI; the city's metadata record says only "free, public data").
• Street names: Helsingin kaupungin yleisten alueiden rekisteri, WFS layer YLRE_Katualue_alue. CC BY 4.0. "Lähde: Helsingin kaupungin yleisten alueiden rekisteri. Aineiston ylläpitäjä on Helsingin kaupungin kaupunkiympäristön toimiala."
• The land front of 1914–1918: City of Helsinki, Helsingin ensimmäisen maailmansodan aikaiset maalinnoitukset, a survey of 1996. CC BY 4.0.
• Defences of the two wars: Finnish Heritage Agency (Museovirasto), register of ancient and historic remains, WFS rajapinta_suojellut:muinaisjaannos_piste and muu_kulttuuriperintokohde_piste, and each site's page in the register (kyppi.fi) for its dating and description. CC BY 4.0.
• War damage: Helsinki City Museum's photos in Finna (as for the archive photos), public domain (PDM).
• Tram, rail and metro tracks: OpenHistoricalMap, CC0.
• Parking fines: City of Helsinki, Pysäköintivirheet Helsingissä, WFS layer (2023) and the yearly CSV files of 2014–2022. CC BY 4.0.