Local Street Gazetteer
A National Street Gazetteer (NSG) is managed by Geoplace on behalf of all UK local authorities. Each Authority supplies a list of streets referenced using a Unique Street Reference Number (USRN) to Geoplace. The USRN's begin with a 2 digit code that relates to specific authorities and all of Birmingham's USRN's begin with 27. The Gazetteer holds against each USRN the Street Name, Town, centre line mapping co-ordinates and a Locality where the street passes through more than one ward or where the street name is duplicated in Birmingham. The geographic information allows reporting of the data held on a ward or street basis and allows data to be displayed within a digital mapping system.
One of the primary uses of the LSG is to assist in the management of the New Road and Street Works Act where Public Utilities such as the Gas and Electricity companies are required to notify local authorities of their intention to carry out work in a street by digitally sending a notice over the internet referenced against the USRN. Additional information regarding each road is linked to the USRN relating to its construction thickness and identifying streets with special considerations such as special construction needs, protected streets, special surfaces, environmentally sensitive areas, structures, pipe lines or traffic sensitivity. The utility companies use this information to identify reinstatement thicknesses to use when restoring the street and to plan for any special considerations they must make when carrying out the work.
The Street Gazetteer also contains information about Highways Maintained at Public Expense. This information is based on List of Streets, compiled in accordance with S36 of the Highways Act 1980, which can be accessed here.
GeoPlace carry out a series of validation checks on the LSG and the additional information and add it to the National Street Gazetteer website hub where it can be accessed by the Public Utilities.
In order to conform with BS7666 part 1, Birmingham produces a level 3 LSG that includes mapping co-ordinates at the start and end of each road and every intersecting street junction therefore breaking it down into elementary street units and the shaping vertices relating to the geometry of the street. This effectively gives a centre line representation of each street.