With a population within the city boundary of around 300,000 rule-of-thumb metrics suggest approximately 120-140,000 buildings in the city. At the time of writing there are around 40,000 buildings mapped.
Why map buildings?
Mapping buildings in the absence of an importable source of vector data is rather time-consuming and fiddly. It is therefore worth considering what the value of adding buildings may be.
- Surface area covered by buildings. Not completely a proxy for all areas with impermeable surfaces but a significant starting point.
- Building orientation for assessment of solar power potential (see OpenSolarMap
- Better visualisation & placement of address information. Particularly important for block of flats, retail areas where the location of entrances is particularly useful.
- Large building footprints give a much better overview of the actual layout of campuses or industrial areas with many large buildings.
- Lastly, one some areas have all buildings mapped this sets a standard for achievable completeness, and ultimately to maintain consistency across the city it eventually becomes necessary to add buildings.
History & Sources
Buildings have been mapped in Nottingham since availability of early Yahoo imagery. Bing imagery became available in 2010 with greatly improved resolution (to zoom 21 in much of the city). From 2013 Bing imagery resolution declined although rectification accuracy improved, as did uptodateness of the data.
Other imagery source for mapping buildings are:
- Mapbox. Less resolution than Bing and with some cloud cover
- Digital Globe layers.
- EA Lidar data (from roughly around 2008) at 1 or 2 m resolution. Most useful for better placement of buildings, but fine for larger buildings.
- OS OpenStreetView. For inner-city areas buildings are merged into single large areas. In suburban areas the building outlines are generalised. Some work was done using Tim Sheerman-Chase's tool to extract buildings from OSSV in 2011 and limited numbers were imported in the Meadows, but quality of extraction and orthorectification were too low to continue with this approach (somewhere SK53 has 600k buildings for the whole of Nottinghamshire). West Bridgford buildings were also sourced this way. The Meadows buildings were replaced as the area was systematically surveyed, but many of the Bridgford ones still remain.
- OS OpenMap. These is a vector layer, approximately congruent with OSSV: many building outlines are still too generalised for use in Nottingham.
Simple 3D Buildings
To date very few Nottingham buildings have been augmented with Simple 3D buildings tags.
- Older Churches, say (up to Victorian times)
- Other listed Grade I and Grade II* buildings
- Significant large civic or community buildings, e.g., the two large shopping centres, QMC.
- University Campuses
- Specific classes of housing (see Nottingham/Buildings/Council Housing for example)
- Industrial estates
- Retail parks
- Other larger buildings