- Where does the OS MasterMap Address Layer 2 data come from?
Similarly to OS MasterMap Address Layer data, Address Layer 2 data is based upon matching the Royal Mail Postcode Address File (PAF) to the buildings in the Topography Layer. The link between the Address and the Topography Layer building is twofold: firstly, implicitly based upon spatial intersection of the matched address feature coordinate position and the topographic area building feature it relates to; and secondly, explicitly since the Address Layer 2 attributes include the TOID of that related building feature. New or changed addresses are notified to Ordnance Survey via a monthly update to PAF and are matched to the Topography Layer, either by field visits or by relating to information already captured.
OS MasterMap Address Layer 2 also offers significant enhancements to Address Layer, such as geographic alternatives, building name aliases, Welsh alternatives and two new datasets – Objects without postal addresses (OWPAs) and Multi-occupancy without postal addresses (MOWPAs). This data is sourced from Royal Mail and Ordnance Survey.
- Are all addresses in OS MasterMap Address Layer 2?
OS MasterMap Address Layer 2 contains addresses supplied to Ordnance Survey in the Royal Mail’s PAF and Multi-Residence File (Multi-occupancy without postal addresses or MOWPAs), together with addresses for the Objects without postal addresses (OWPAs) that have been derived from a number of different Ordnance Survey datasets.
- Are the OS MasterMap Address Layer 2 addresses in the right place?
Each address is coordinated on the National Grid, with eastings and northings normally quoted to a resolution of 0.1 metre. The coordinate is positioned within the building the address applies to (if applicable) and the TOID of that building is provided; the coordinate does not reflect the precise location of the delivery point to the building. The positional quality of the coordinate is specified by the positionalQuality component of the addressStatus attribute of the address feature as follows:
Final – Surveyed: addresses that are matched to a final position.
Provisional – Approximate: addresses matched to an approximate position (usually within 50 m); for example, a temporary building such as a site office.
Provisional – Estimate: addresses matched to the centre of a postcode unit (for example, SO40 8EY).
Provisional – Postcode Sector Mean: addresses matched to the centre of a postcode sector (for example, SO40 8).
Provisional – Postcode Unit Mean: addresses that have only estimated positions, usually because they have a new postcode that does not correlate with any existing postcode.
Some addresses are non-geographic, such as Post Office boxes, which are usually matched to the relevant Royal Mail sorting office; this will not be the point where the mail is actually delivered.
While addresses and buildings are maintained simultaneously (both in capture of real-world change and in positional accuracy improvement processes), it is not yet possible to generate the OS MasterMap Address Layer 2 and Topography Layer products from the maintained database simultaneously. This may mean that, very occasionally, a user may find an address coordinate outside a topographic building, even though they downloaded both layers on the same day.
Post Office is a registered trademark of Royal Mail Group plc.
- Are there any plans to withdraw ADDRESS-POINT or Address Layer?
Yes- from 31 October 2014 we have announced the formal withdrawal of all these products. Please see the questions and answers. Current customers will continue to get updates until 31 October 2015. The deadline for any new contracts or orders for new areas is 1 April 2015.
Address Layer 2 provides precise coordinates for more than 27 million residential and commercial properties in Great Britain.