> For the complete documentation index, see [llms.txt](https://docs.os.uk/more-than-maps/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/more-than-maps/using-addressing/a-guide-to-using-os-ngd-address-for-emergency-services.md). # A Guide to Using OS NGD Address for Emergency Services ## Introduction Accurate location information is fundamental to emergency response. Whether handling a 999 call, mobilising resources, supporting operational planning, or conducting post-incident analysis, emergency services rely on authoritative and up-to-date address data. OS NGD Address is part of the [Ordnance Survey National Geographic Database (OS NGD)](https://docs.os.uk/osngd/introduction-to-os-ngd/os-ngd-explained) and provides a modern address dataset designed to support operational and strategic use cases across blue lights and other resilience organisations. This guide outlines how emergency services can maximise the value of OS NGD Address and adopt best practice when integrating address data into operational systems.
Image showing buildings with address seed for each
## What is OS NGD Address? OS NGD Address is Ordnance Survey's next-generation addressing dataset. It provides definitive addressing information for the United Kingdom, built around the Unique Property Reference Number (UPRN) and integrated with other OS geospatial datasets. OS NGD Address contains all the address data found in the [OS AddressBase Premium](https://docs.os.uk/os-downloads/addressing-and-location/addressbase-premium) product and more. Key benefits include: * Up-to-daily currency * Representation of Local Authority and Royal Mail addresses * Address lifecycle information, including pre-build and historic address * Accessible ‘plug-and-play’ CSV format with no pre-processing * Interoperable with other OS NGD themes including buildings and land-use * Persistent unique identifiers across all feature types – including UPRN, USRN, and UDPRN * Full UK coverage when accessing OS GB Address and OS Islands Address together. ## Why adopt OS NGD Address? ### Comprehensive addressing The OS NGD Address theme includes authoritative and trusted Local Authority derived addresses across five feature types and is served alongside the Royal Mail Address feature type, integrating the full Royal Mail Postcode Address File (PAF) with additional Ordnance Survey address attribution. PAF is Royal Mail’s address database, which captures delivery point addresses identified as able to receive post. It is the PAF that supplies local authority addresses with official postcodes. Royal Mail use the Unique Delivery Point Reference Number (UDPRN) as a unique identifier. Including the full PAF into OS NGD Address provides greater visibility of the relationship between UPRNs and Royal Mail UDPRNs, including the ability for multiple UDPRNs to be associated with a single UPRN and the identification of unmatched UDPRNs. Unlike previous OS addressing products, which did not expose these relationships, the Royal Mail Address feature type enables users to identify addresses captured by Royal Mail that have not been matched to a corresponding local authority address. This delivers a more complete view of the national addressing landscape and helps cover potential gaps in local authority address records. ### Up-to-daily currency OS NGD Address offers daily updates and a Change Only Update (CoU) service, significantly reducing the time between local authority or Royal Mail address changes being received by Ordnance Survey and becoming available to users in product. Compared with AddressBase Plus and AddressBase Premium, update latency is reduced from approximately eight weeks to around five days, enabling faster access to the most current address information. ### Connectivity across the NGD OS NGD Address allows for linking UPRNs directly to buildings, land use sites, and other NGD themes, removing the need to maintain and join multiple datasets. Users can enrich addresses with building attributes such as height, number of storeys, and construction materials, and connect addresses to complex sites such as hospitals, universities, and industrial estates. Previously, deriving these relationships from OS data required users to source, maintain, and join multiple datasets. The NGD provides these connections out of the box, reducing complexity and offering faster insight into the relationship between operations and geographies. ## How is OS NGD Address structured? *Note, reflective of latest schema versions as of October 2026* OS NGD Address is broken into two collections – GB and Islands. Both collections contain six feature types: * **Historic Address** – Local authority addresses that are no longer in existence. * **Pre-Build Address** – Local authority addresses yet to be built but have been granted planning permission or are under construction. * **Non-Addressable Object** – Local authority and Ordnance Survey captured objects that would not be expected to be able to receive mail or deliveries. * **Street Address** – Address locating the Street that Property and Non-Addressable Objects are located on or near to. * **Royal Mail Address** – Royal Mail delivery point addresses with additional attribution describing their relationship with local authority addresses. Each feature type (excluding Street Address and Royal Mail Address) is also supported the following three related component tables, which provide supplementary information against each UPRN: * **Alternate Address** – Alternative address labels where they exist for the ‘current’ address represented on a given feature type. * **Other Classification** – Additional VOA classification information. * **Related Entity** – Cross-reference relationship information between addresses and features in other OS NGD themes (such as buildings, sites, roads and boundaries) or third-party data sets. Royal Mail Address is supported by three other related component tables that provide supplementary information against each UDPRN: * **Multiple Residence** – Identify addresses with a shared delivery point. i.e. one front door for subdivided flats, units, or other separate occupancies. * **Delivery Point Alias** – Alias data related to a delivery point address, sourcing data from Royal Mail's Delivery Point Alias (DPA) table. * **Other Alias** – Alternate names for counties, localities and thoroughfares.
Diagram showing structure of address data
## How is OS NGD Address supplied? ### File Formats OS NGD Address feature types are available in two file formats – GeoPackage and CSV (comma-separated values). For gazetteers in the emergency services, the CSV format is recommended for both software compatibility and familiarity. ### Currency & Filtering OS NGD Address offers three order frequencies; Daily, Monthly, and Annual Supply. Data can also be ordered based on geography; taking all of Great Britain or an area-of-interest, which can be specified or predefined. Change-Only Updates (COUs) are available for CSV supplies of OS NGD Address. These files come with the benefit of providing only the features which have changed since your last supply, reducing the overall size of the files you receive. Note, COU files are only available daily and monthly with unfiltered data (full GB coverage, with no [OS Select+Build](https://docs.os.uk/osngd/getting-started/downloading-with-os-select+build) filters applied). For gazetteers in the emergency services, a daily COU supply is recommended in order to ensure that the most up-to-date address information possible is available at all times. A COU file will contain any changes which have been made to the underlying data within the selected time frequency. If no changes have been made to that feature type, then the COU file will be blank. This will always occur for files released on a Sunday, when no local authority changes have been received. A single feature may be updated multiple times in a single COU file. This would happen where a single feature has changes committed in OS’ product databases more than since the last COU. Instead of suppressing all changes other than the last edit, your COU will contain all edits made to that feature. This is likely to occur more commonly if you choose to take a monthly supply but could also occur in a daily COU. ## Best practice for emergency services Like any addressing dataset, there is guidance for getting the most out of the OS NGD Address theme. ### Use UPRNs Wherever Possible Adopt the Unique Property Reference Number (UPRN) as the primary identifier for locations across operational systems. Where practical, incidents, assets, premises risks, and operational records should be linked using UPRNs ### Exploit Address Lifecycle Information Whilst Built Address may meet most gazetteer requirements, utilising lifecycle feature types (Pre-Build and Historic) will add additional coverage of the address landscape in GB, including new housing developments under construction / not yet occupied, and historic addresses that may still be known to the public. ### Incorporate Royal Mail Addressing Adopt Royal Mail Address to ensure coverage of unmatched postal addresses. The public may provide an address that local authority records. By including the unmatched records of Royal Mail address, such a scenario can be accounted for. ### Adopt Daily Updates Minimise lag between local authority address updates and your gazetteer by adopting daily COU ingest. Note, COU files do not necessarily need be ingested daily as long as they are ingested in order of release when they are loaded into a gazetteer. ### Establish Data Governance Assign ownership of gazetteer updates and processes to ensure updates are regularly applied and validated. Ensure every operational system uses the same address source & currency, so that every responder sees the same location. Be resilient – maintain backups and the ability to rollback your gazetteer if required. Escalate issues – report observed errors to OS and / or to your CAD supplier. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.os.uk/more-than-maps/using-addressing/a-guide-to-using-os-ngd-address-for-emergency-services.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.