Improvements to AddressBase Representative Point Codes

Improvements to AddressBase Representative Point Codes

Beginning in October 2018 (Epoch 62) and concluding in December 2018 (Epoch 64), you’ll notice some changes to the way Representative Point Codes (RPCs) are calculated in our AddressBase products.

Jump to:
What's changing? | Why now? | Which records are in scope? | New RPC code descriptions | Do I need to do anything? | Current RPC code descriptions | Help using the products | FAQs

What's changing?

For these changes we'll use our large-scale topographic data with additional information provided by local authorities, to validate the RPC assigned to a UPRN. This will mean that where Unique Property Reference Numbers (UPRNs) fall inside a building present on our large-scale mapping, the RPC will automatically be calculated to form a relationship with that building. Additionally, improved validation will be put in place for Street Records (PS) to form a relationship between the UPRN and the street start and end coordinates in product.

These RPC changes to our AddressBase products will:

  • Enhance analytical capability.
  • Improve cross-product relationships.
  • Ultimately allow you to make better informed decisions when using the AddressBase products portfolio.

Why now?

Many customers have asked us to improve this attribute, with it being a valuable filter and indicator of quality. The new method of calculation and improved descriptions mean customers will be able to use this attribute with confidence.

The three epochs between 62-64 represent a rare opportunity to make these changes without affecting other important product improvement programmes. If this opportunity is not taken it will result in a significant delay to the roll-out of these improvements.

Which records are in scope?

It's important to note that not all UPRNs will have their RPC value assigned using this new methodology. For records correctly captured outside of buildings (e.g. Advertising Hoardings, Parks and Caravans), local authority information will continue to be used. This is also true for historic and provisional records (only contained in AddressBase Premium).

New RPC descriptions

As we're going to introduce complete product consistency to the RPC attribute, we also wanted to take the opportunity to improve our descriptions. These descriptions don't currently reflect how the data has been captured. Therefore by introducing a set of clarified descriptions at the same time as applying a new calculation, the RPC attribute will be clearer and easier to use.

It's important to note the codes these descriptions correspond to haven't changed.

Code within AddressBase data (unchanged)
Code description

Central Internal Position

The address seed is contained within, and not further than 2.5m away from, the calculated centre of the OS MasterMap Topography Layer surveyed building it is contained within.
The seed is in the best possible position based on the nature of the premises e.g. Development Land, House Boat, Wind Farm.


General Internal Position

The address seed is contained within an OS MasterMap Topography Layer surveyed building but is further then 2.5m away from the centre.
The seed is in an internal position based on the nature of the premises e.g. Development Land, House Boat.


Transitional Position

The address seed has been changed from provisional to live in the last six months. It has been captured to a high level of positional accuracy but the OS Mastermap Topography Layer building is not present.

The address seed will only be moved pending any imminent mapping updates.


Street Location

The address seed is plotted in accordance with the declared street start or end coordinates.
Please note this is the highest accuracy possible for Street Records.


Postcode Unit Position

The address seed has been captured to Postcode Unit level. It will be updated when more information becomes available.

9 This address seed has been captured to a lower level of accuracy and will be updated as a priority over the coming releases.

In summary, we are now calculating the central point of each building and checking the address seed against it.

    • If an address is inside a building and is within 2.5m of the central point it will be assigned an RPC of 1.
    • If the address is located in a building but not within 2.5m of the centre it will be assigned an RPC of 2.
    • For newly created live addresses yet to be contained within a building, instead of downgrading the value assigned to these records, they will be allocated an RPC = 3 for six months to allow time for potential large scale mapping updates.
    • If the location of the address matches the declared street start or end coordinates it will be assigned an RPC = 4.

  • If the location does not match the street coordinates but is contained within the appropriate postcode area it will be assigned an RPC = 5.
  • Lastly if the UPRN has still not been allocated a value at this point it will be assigned an RPC = 9.

Do I need to do anything?

No. The RPC improvements will result in larger volumes of data than normal for Change Only Update customers. These will be managed to ensure supply volumes are manageable, with increased changes limited to approximately 4 million across the whole of GB per epoch. You should not need to make any changes in advance as the codes within the products will remain unchanged.

See our AddressBase release notes for details on the amount of changes completed in each epoch.

Current RPC code descriptions

You can find information on the current RPC code descriptions in our AddressBase technical specification documents:

More help using AddressBase products

You can also visit our support pages for more guides, useful links and FAQs:


What do I need to do beforehand?

Nothing. Familiarise yourself and your organisation with the new definitions that will be used, and ensure you are ready for a larger-than-usual volume of COU, but as the data structure and schema remain the same there should be no need to change any databases or processes to accommodate this change.

Do I need to take a new baseline (Full Supply) of data?

No. We will provide you the updates in line with your current contract; therefore if you are a Change Only Update (COU) customer you will receive these changes within your normal COU.

Can you tell me how much larger the updates will be?

In total there will be approximately 12 million changes across the 3 epochs, but some of these records would have changed as part of the normal update cycles.

I take a Full Supply, how will this affect me?

You'll see the same changes as Change Only customers as we want to ensure you are synchronised with all AddressBase users. Therefore you should familiarise yourself with the updates being made, but you will see no changes in data volumes.

How are the new codes being calculated?

We're using OS large-scale data to ensure that the relationship between a building and the address point within it is correctly attributed with the relevant RPC code. These will be guided by a consistent set of rules across GB.