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Chapter 1: Unique Property Reference Number (UPRN)#

Imagine you're working on a building project using BIM (Building Information Modeling). Your model contains lots of information about the design, materials, and structure. But what about connecting this detailed model to information outside your project? Like, has this building had planning permission? What utilities connect to it? Who owns the land?

This external information is often stored in many different databases, and they might all describe the same building or location using slightly different addresses ("10 High St", "Ten High Street", "High Street 10"). How can you be sure you're looking at the same place every time?

This is where the Unique Property Reference Number (UPRN) comes in!

What is a UPRN?#

Think of the UPRN like a permanent, official ID number specifically for places. Just like you have a unique ID (maybe a passport number, social security number, or national insurance number) that identifies you uniquely, a UPRN identifies a specific addressable location in Great Britain uniquely.

The UPRN is a special number managed by Ordnance Survey (OS), the national mapping agency, in partnership with local authorities.

Here's what makes a UPRN special:

  • Unique: No two addressable locations have the same UPRN.
  • Persistent: Once a UPRN is assigned to a place, it stays with that place forever, even if the street name changes, the building is modified, or even if it's demolished and rebuilt later. It refers to the location, not just the current building on it.
  • Comprehensive: It's assigned to more than just houses and shops. It covers almost any place that can receive mail or needs to be officially referenced, like building entrances, pieces of land, and sometimes even temporary structures or other features.

As the OS Open UPRN Overview Summary tells us, the OS Open UPRN dataset provides this number along with the location (coordinates) for every addressable point in Great Britain. It's designed specifically to help people link different datasets together.

Why is the UPRN Important for Linking Data?#

Because the UPRN is unique and persistent, it acts as a reliable common key or connector between different datasets.

Let's go back to our BIM project example.

  1. Your BIM model represents a building at a certain physical location. You might have its street address.
  2. You can use a dataset like OS Open UPRN (which provides UPRNs for addresses/locations) to find the official UPRN for your building's location.
  3. Once you have that UPRN, you can then look up information in other datasets that also use UPRNs, like:

So, instead of trying to match messy address text, you match a simple, reliable number: the UPRN. This makes finding and connecting information much easier and more accurate.

How Do You "Use" a UPRN?#

In practice, using a UPRN often involves two main steps:

  1. Finding the UPRN: Given an address, a location (coordinates), or perhaps a record from another dataset, you find the corresponding UPRN using a UPRN lookup service or dataset (like OS Open UPRN).
    • Example Input: Address: "10 High Street, Anytown, AB1 2CD"
    • Process: Look up this address in a UPRN database.
    • Example Output: UPRN: 10002331234
  2. Using the UPRN to Link: Once you have the UPRN, you use it to query other datasets that contain information indexed by UPRN.
    • Example Input: UPRN: 10002331234
    • Process: Search a planning application database for this UPRN.
    • Example Output: A list of planning applications submitted for the location with UPRN 10002331234.

This process lets you pull together relevant information from many different sources, all related to the same physical place.

The basic structure of the OS Open UPRN data that enables this linking is quite simple, as shown in the OS Open UPRN bSDD Data Dictionary:

| PropertyUnit | `uprn`         | Unique Property Reference Number                        | Integer | none |
| PropertyUnit | `geometry`     | Point location of the UPRN                              | Geometry| none |
| PropertyUnit | `theme`        | Dataset classification (e.g. Property, Address)         | String  | none |
| PropertyUnit | `postcode`     | Associated postcode                                     | String  | none |
... (other attributes)

The key fields are uprn and geometry (which includes location coordinates like latitude/longitude or easting/northing).

Behind the Scenes: A Simple Workflow#

How does using the UPRN connect things? Here's a simplified look at what happens when you use a UPRN dataset to find information:

sequenceDiagram
    participant YourSystem as Your BIM/GIS System
    participant OSOpenUPRN as OS Open UPRN Data
    participant ExternalData as External Planning/Utility Data

    YourSystem->>OSOpenUPRN: I know the location (coordinates) or address of my building. What's its UPRN?
    OSOpenUPRN-->>YourSystem: Looks up the location/address in its database.
    OSOpenUPRN->>YourSystem: Here is the UPRN: 10002331234.
    YourSystem->>ExternalData: I have UPRN 10002331234. Give me all records related to this UPRN.
    ExternalData-->>YourSystem: Finds matching records by UPRN.
    ExternalData->>YourSystem: Here are the planning applications and utility connections for UPRN 10002331234.

This diagram shows how the UPRN acts as the bridge, allowing you to start with information you have (in your system) and find related information in other places.

The OS Open UPRN data itself is quite straightforward. It's often provided in formats like CSV or GeoPackage. Let's imagine looking at the start of a simple CSV file from the OS Open UPRN dataset (referencing the attributes mentioned in OS Open UPRN Overview Summary):

UPRN,X_COORDINATE,Y_COORDINATE,LATITUDE,LONGITUDE
10002331234,530100,180450,51.5074,-0.1278
10002331235,530110,180460,51.5075,-0.1276
10002331236,530120,180470,51.5076,-0.1274
...

This simple table is the core of the OS Open UPRN dataset. Each row links a unique UPRN to a specific point location (X_COORDINATE, Y_COORDINATE, LATITUDE, LONGITUDE). You can use the coordinates to find nearby UPRNs, or if you know the address and can get the coordinates, you can find the specific UPRN. Then, you use that UPRN value to search other datasets that also contain a UPRN column.

For example, in a data analysis tool, you might read this data:

# This is example Python code showing the concept
# Imagine 'uprn_data.csv' is the OS Open UPRN data

import pandas as pd

# Read the first few rows of the data
df = pd.read_csv('uprn_data.csv', nrows=5)

# Display the data
print(df)

This small code snippet would just load and show the first few lines of the UPRN data, letting you see the UPRN column and its associated coordinates. This data is what allows you to look up a UPRN based on a location.

Then, if you had another dataset, say planning_applications.csv, which also had a UPRN column:

PLANNING_REF,UPRN,DESCRIPTION
APP/2023/1234,10002331234,Erection of rear extension
APP/2024/5678,10002331236,Change of use
...

You could use the UPRN to link them:

# Imagine 'planning_applications.csv' is the external data

# Read the planning data
df_planning = pd.read_csv('planning_applications.csv')

# Find all planning applications for the UPRN 10002331234
relevant_applications = df_planning[df_planning['UPRN'] == 10002331234]

# Print the result
print(relevant_applications)

This minimal example shows the power of the UPRN: finding the number in one place (OS Open UPRN data) and using it to filter or join data from another place (planning applications).

Conclusion#

The Unique Property Reference Number (UPRN) is a fundamental building block for connecting information about locations and properties in Great Britain. By providing a standard, persistent ID for addressable places, it allows you to reliably link your BIM projects and other location-based data to a wealth of external information, like planning records, utility networks, and ownership details.

Understanding and using UPRNs is key to working with many UK datasets that are relevant to the built environment.

However, sometimes you need to identify the features on the ground – like the outline of a specific building, a road, or a fence – which might not always align perfectly with a single address point. For that, we often use a different identifier.

In the next chapter, we'll explore the Topographic Identifier (TOID) and how it complements the UPRN by identifying specific geographic features.

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