Sources and method

A proof of concept covering the old City of Toronto (the pre-1998 boundary). The map shows the buildings that stand today, each appearing in the year it was built. Buildings that were demolished are not shown.

Where each building's year comes from

Toronto publishes no year-built record for its buildings, so each building takes its year from the best source that covers it, in this order. The "Data quality" button colours the map by source.

The old shoreline

Over today's land, the map paints the water as drawn on ten historic maps from 1834 to 1931, so the harbour, the peninsula that became the Island, and the marsh at Ashbridge's Bay appear as they were. Each map blends into the next over the eight years before it. Before 1834 the 1834 map is used.

What is approximate or added by hand: the 1858 breach that cut the peninsula is a rectangle placed at the Eastern Gap; the Island keeps its 1851 outline until about 1910 and is today's Island after that, because the later source maps do not draw it; the marsh is the 1834 outline until the 1891 map; the last mapped shore (1931) gives way to today's between 1950 and 1960, which is a choice and not a record of when each piece of landfill was finished.

Hand-built landmarks

The CN Tower, the Rogers Centre and BMO Field are built by hand from simple shapes, because the City's model shows them as plain blocks (and leaves BMO Field out). Heights and dates come from the Wikipedia article for each: the CN Tower's 553.3 metres, its 102-metre antenna and the levels of its pods; the Rogers Centre's 86-metre roof; BMO Field's pitch and the years its upper deck and roof were added. Outlines are OpenStreetMap's. Everything else, such as the width of the tower's legs, the curve of the dome and the heights of the stands, is judged from the outline and from photographs. Each rises over the years it was under construction. The Rogers Centre is shown with its roof closed.

The old Trinity College on Queen Street West is also built by hand: its footprint is the one on Goad's plan of 1913, and its heights, central tower and turrets are judged from an early postcard view. It stands from 1851 to 1956; sources give the demolition only as "the 1950s".

Lost buildings

Between Bathurst Street and the Don, from the lake to Bloor Street, the map also shows buildings that are gone. They are read off Charles Goad's fire insurance plans of 1880, 1889, 1903, 1913 and 1924, which draw every building and colour it by material. A program picks out the coloured outlines from the georeferenced scans; nobody traced them by hand.

From the plans: the outline, and whether the building was brick or wood. Estimated: the years. A building first seen on one plan went up some time after the plan before it, and the map picks a year in that gap; the same goes for the year it came down. Buildings already on the earliest plan are spread back to the date of their street in step with the city's population. Buildings still on the 1924 plan stay until the year before the building that stands there now, or, where nothing stands there now, until the typical year for their lost neighbours. Assumed: the heights (6.5 metres for wood, 10 for brick).

What this gets wrong: rows of houses often come out as one block; lettering on the plans leaves gaps; a building can flicker at a plan year where two plans draw it differently; anything built and demolished between 1924 and today is missing, as is everything outside this district. Click a lost building to see which plan it comes from.

Two places outside that district are read the same way. The Toronto Islands, from the Island plates of the 1913 and 1924 plans: the shape of the Island and its lagoons from 1913 on, and the cottages, hotels and park buildings on Hanlan's Point and Centre Island. When they were built and cleared comes from written sources as a range of years for each part of the Island (data/manual/island.csv and lost_zones.csv); each building gets a year in that range. The houses on Ward's and Algonquin still stand and are shown as today's buildings. On the Island plates, anything long and thin, larger than a hotel, or off the Island's land is left out, because the plates lie on an index map whose ruled lines and coloured strips would otherwise be read as buildings.

Streets and place names

There is no modern base map. The streets are those of the City's centreline file, which has no dates, so every street's year is an estimate. A stretch of street gets the earliest of: the years of the buildings along it and around it; the ten-block townsite of 1793; and the built-up town as drawn on the maps of 1834 (Chewett) and 1842 (Cane), outlined by eye from the georeferenced scans. Where an opening year is documented (Yonge Street, University Avenue, the Gardiner Expressway and about forty other stretches) it replaces the estimate. No street appears before its ground was dry land.

What this gets wrong: only streets that exist today are shown; where every old building is gone, a street appears too late; street names are today's in every year; some documented years are a survey or a first mention, not an opening. Creeks are not drawn. Today's Don River channel shows in every year.

Railways are today's tracks, from OpenStreetMap, shown from the year each line opened (data/manual/rail_years.csv, one source per line). Along the harbour today's tracks lie on ground filled in later, so there the line is moved to the shore of each mapped year, which is about where the first tracks ran.

Forest: in 1793 all the land is shown wooded, which is an assumption. For 1851 the woods are those drawn on J.O. Browne's Map of the Township of York, picked out of the scan by a program that looks for the map's tree symbols; it misses some woods and takes some orchards and worn paper for woods. Between 1793 and 1851 the clearing spreads out from the first roads, which is an estimate. At every date a place is cleared when a street or building comes within 150 metres.

Parks, cemeteries and golf courses are today's, from the City's Green Spaces file, which has no dates. They are shown green in every year once the forest around them is gone, whenever they were really laid out. Ponds and rivers are today's.

Fort York: every building inside the ramparts is dated 1815, the year the rebuilding begun in 1813 was finished. That is wrong for the Blue Barracks, a reconstruction of 1986, and for a few small modern service buildings. The ramparts are today's outline.

Place names appear for the years they were in use. Each has a source, listed with the estimated dates and label positions in data/manual/places.csv and places_README.md.

Data

Contains information licensed under the Open Government Licence - Toronto.