Birmingham completely covered with buildings

posted in: Map Improvements | 3

Today West Midlands mappers have  passed another major milestone: Birmingham has complete coverage for buildings!

Complete coverage does not mean we have EVERY building mapped, just that we’ve covered every area of the city. There will be the inevitable errors from buildings having been built and demolished and just from human error in missing a building. We welcome news from  the keen-eyed of any errors so we can improve the map even further.

It has taken two years of effort (often very tedious) tracing buildings from our own aerial imagery (supplied by Cities Revealed for the City Centre) and latterly from Bing. For new developments (new housing estates, industrial estates, supermarkets and demolitions) we have had to compare Bing with the latest release of OSSV which is newer and reveals a later state of building coverage. Nevertheless we reckon that we have the most accurate and complete coverage of any online map of Birmingham.

While we’ve been at it the other local authority areas in the West Midlands have also obtained pretty good building coverage. Estimates are:

Solihull
70%
Sandwell
30%
Coventry
20%
Dudley
10%
Wolverhampton
10%
Walsall
10%

Thanks are due to everyone who’s contributed – especially the 6 or so mappers who have contributed most of the work.

For those of you reading this outside the UK who might be thinking “ What’s the big deal?” every building has been traced by hand – we have no data import of building outlines available to us.

You can see a good visual analysis of coverage by using the excellent tools at ITOworld’s map service.

Of the 290,000 buildings added, 69,000 have full address information, complete with postcode.

The building count we estimate is under-represented by a factor of 8, as many are just represented by an outline rather than individual addressable units. For instance, a row of terraced houses of which Birmingham has hundreds, once surveyed and terraced with individual addresses can become up to 40 buildings, depending on the length of the terrace instead of one. This all depends of course on your definition of building; but we’re basing this on OSM tagging of building=residential (or similar in other circumstances) for each address.

There are over 400 tags applied to buildings; here are some of the more prevalent ones:

Tag
Qty
Listed Building
1,400
Residential
137,000
Retail
2,000
Garage/Garages
4,500
Yes
134,000
Industrial
1,000
House
5,000

Amongst the bewildering variety of tags we even have a chimney mapped! This is probably an old industrial artefact of some prominence. Anyone want to try finding it? (The person who mapped it is exempt from this challenge!)

All figures are for the West Midlands as a whole rather than just for Birmingham, and are rounded to the nearest thousand.