Buildings on the parcel

What we use

Overture Maps Buildings, the open map of buildings published by the Overture Maps Foundation. It brings together the ground plan of each building drawn by three sources: OpenStreetMap, the map made by volunteers, and the maps that Microsoft and Google trace from aerial images. Where the source gives them, it also has height, number of floors and type of building. Overture publishes a new edition every month and the report states which one it used. Licence ODbL 1.0.

How we use it

The report takes the plot of the address, that is the cadastral parcel (particella), and looks for the buildings drawn on it. Cadastral maps and open maps do not match to the metre, so a building counts as "on the plot" if at least half of its ground plan falls inside, or if it covers at least half of the plot: this happens in historic centres, where a whole block is drawn as a single building. In that case the measurements only use the part on the plot.

For the plot it shows:

• how many buildings there are;
• the ground footprint, that is how many square metres they cover together, without counting overlapping parts twice;
• how much of the plot they cover;
• the tallest height and the highest number of floors, if the source gives them.

It then lists the buildings from the largest, up to 10 (the total is always given), with the type in plain words (block of flats, house, garage, warehouse and so on), the footprint, the height, the floors, the map it comes from and which building contains the address.

Where there is no cadastral parcel, as in the provinces of Trento and Bolzano, the block describes the building that contains the address point or, if the point falls outside, the nearest one within 15 metres.

The same ground plan is also used to estimate the roof on the page about sun and solar panels. It is an information block: it gives no score.

Limits

• It is not an official source: some buildings may be missing or drawn roughly, especially those traced from aerial images.
• Measurements are taken from the map, not from the cadastral floor plan. The plot area is also measured on the cadastral map drawing and is approximate.
• Height and floors are only available for some buildings. When they are missing, the report says so and does not estimate them.
• A building that has just been built or demolished may not yet be updated on the maps.
• The block is about the whole building, never a single flat: for flats you need a visura catastale, the official land registry record.
• If no building shows up on the plot, it may be open land, a courtyard or a building that has not been drawn yet: the report says exactly that.

The plot and its boundaries come from the cadastral maps.

Official page: Overture Maps, buildings.