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Maintaining the National Address Gazetteer infrastructure

Providing and maintaining a national address data set that is robust, consistent and accurate enough for users such as the emergency services and commercial organisations necessitates a complex infrastructure able to take data feeds from hundreds of different organisations.

There are a number of tasks involved in maintaining such high quality information, including: data validation; data modelling; quality assurance; systems and data integration; information security; performance optimisation; stakeholder and user engagement. 

There is also a significant number of addressing experts who support both the National Address Gazetteer infrastructure and the use of AddressBase products by customers of Ordnance Survey. This ranges from database experts, GIS / database technical support and consultants, as well as Relationship Managers - all of whom work towards ensuring that customers of AddressBase products get the best value out of the data content.

We receive over 5,000 update files per month from local authorities in Great Britain.  Across local authorities as a whole, there are around 2 million records modified and sent to us each month, with the majority of records sent on a daily basis.

Once the records are received, we undertake a large data validation exercise.  This involves testing local authority data against published data compliance conventions though a series of around 500 ‘health checks'. Further checks are carried out on logical data consistency, classification and address mismatches between local authority address data, Ordnance Survey, Valuation Office Agency and Royal Mail's Postcode Address File (PAF).

By taking data from these multiple sources and validating it against each other, users can be confident that change intelligence on the ground is captured.  The role of the local authorities is particularly important in this area. While we undertake the ‘data crunching', local authorities produce the bulk of the data and verify any anomalies in their area.  Of particular value is that the data provided by the local authorities is also used in local business critical applications such as collecting council tax and electoral registration.

The resulting data includes the information from local authorities who have the statutory responsibility to create addresses, postal information from Royal Mail, topographic features from Ordnance Survey and property information from the Valuation Office Agency.  The data also contains geographic coordinates and a unique identifier – the Unique Property Reference Number- for each record which is utilised by many users as a ‘golden thread' to link different datasets together.

The expertise of staff at Ordnance Survey and GeoPlace combined with the close arrangements with local authorities presents one of the most successful large-scale government IT projects that has existed to date.