Guelph Buildings

A reference layer of the building outlines published by the City of Guelph — 38,944 footprints, almost all traced from the City's own high-resolution aerial photography — ready to add to the OpenStreetMap editors iD and JOSM while you map.

City data: 2026-10-09 · tiles rebuilt: 2026-10-09

Contains information licensed under the Open Government Licence – City of Guelph. Source: Buildings.

Preview

The raster layer drawn over OpenStreetMap, from zoom 15: violet outlines were traced from aerial photography, orange ones drawn from a site plan.

Coverage vs OpenStreetMap: see which City buildings have no OSM building on them — a mapper's worklist with an interactive map and table.

Two layers — which to use

Vector layer	Interactive. Click an outline to read its tags (`bldid`, `source`, `area` in m²). Best in iD.
Raster layer	Outlines drawn directly on the tiles. A tracing backdrop over aerial imagery. Best in JOSM.

Add to iD

Vector layer (interactive)

Open the iD editor and press U for the Map Data panel.
Under Custom Map Data, open the settings and paste this URL:

https://guelph-maps.github.io/guelph-buildings-layer/tiles/vector/{z}/{x}/{y}.pbf

Zoom in, then click any outline to see its tags in the inspector.

Raster layer

Open the Background panel and choose Custom.
Paste this URL template:

https://guelph-maps.github.io/guelph-buildings-layer/tiles/raster/{z}/{x}/{y}.png

As a background it replaces the imagery; the vector layer is the one to use over imagery in iD.

Add to JOSM

Raster layer (recommended for JOSM)

Open Preferences → Imagery and click +TMS.
Paste this entry (the tms[15,18] prefix sets the zoom range; JOSM scales it up past z18):

tms[15,18]:https://guelph-maps.github.io/guelph-buildings-layer/tiles/raster/{zoom}/{x}/{y}.png

Give it a name such as Guelph Buildings, click OK, then enable it from the Imagery menu above your aerial imagery. Note JOSM's placeholder is {zoom}, not {z}.

Vector layer (optional)

JOSM can also add the vector tiles via Preferences → Imagery → +MVT:

https://guelph-maps.github.io/guelph-buildings-layer/tiles/vector/{zoom}/{x}/{y}.pbf

Notes

Every building the City publishes is drawn. The City's SOURCE field says how each was captured: all but a few hundred were traced from aerial photography; the rest (orange) were drawn from a submitted site plan, so the building may not be built yet, or not as drawn.
The City captures outbuildings down to a few square metres. Sheds and garages are in the layer; whether they belong in OSM is your call.
Vector tiles are pre-rendered through zoom 19; raster tiles for z15–18 (the editor overzooms them further).
Tiles are refreshed weekly from the City's service.
This is a reference layer — check it against current imagery before copying anything into OpenStreetMap. Where a building in OSM already exists, improve it in place rather than replacing it, so its history and tags survive.