Following user feedback, the method for populating the POSTCODE_LOCATOR attribute in the AddressBase Plus and Premium products has been improved. Prior to Epoch 21, released February 2014, the values in the POSTCODE_LOCATOR field were derived spatially by plotting the BLPU coordinate against Code-Point with polygons.
In some cases this was affecting the usability of the product, most notably:
Ø Where there were 'NULL' values in some records; and
Ø When searching for and matching against local authority addresses that have not been matched to a PAF address.
From Epoch 21 the production rules have changed so that:
Ø If the BLPU is matched to a Royal Mail Delivery Point Address, then the Postcode_Locator shall contain the Postcode from the Delivery Point Address.
Ø If the BLPU is not matched to a Royal Mail Delivery Point Address, the postcode that the Local Authority hold will be used when:
- it is deemed to be 'postally addressable'; and
- it matches the distinct set of postcodes in the current PAF file.
If the BLPU is not PAF matched or the Local Authority does not hold a postcode, then the POSTCODE_LOCATOR is derived spatially by plotting the BLPU coordinate against Code-Point with polygons. Additional care is taken for records:
- falling within 'Vertical Streets';
- on the boundary of two or more Codepoint polygons; or
- outside of the CodePoint with Polygons representation of the coastline.
As a result of these changes, approximately 1.9 million POSTCODE_LOCATOR values have been improved. If you have further questions please contact your Ordnance Survey Relationship Manager.