OS MasterMap Topography Layer

The OS MasterMap Topography layer is presented seamlessly with more than 500 Million real world objects – all uniquely identified - including roads, buildings, parks and waterways all managed and maintained by Ordnance Survey within one of the world’s largest spatial databases.​

  • Topography
  • Download
  • Premium Plan
  • Public Sector Plan

This product is updated every six weeks

Representation of data provided
Representation of data provided
© Crown copyright and database rights. Ordnance Survey 2024

What OS MasterMap Topography Layer provides you with

Mapping from the ground up

In a business of any kind, OS MasterMap Topography Layer gives you the confidence to make location-based decisions about assets, services, environmental risks, customers and operations.

Accurate referencing

Geo-tag your assets, with the topographic identifier (TOID) at the heart of OS MasterMap products. This makes it ideal for monitoring assets such as pipelines, pylons, bridges and warehouses.

Enhanced features

OS MasterMap Topography Layer includes enhanced features - Building Height Attribute to analyse the built environment and Sites Layer showing the main points of access to key sites.

The foundation of the OS MasterMap family

With OS MasterMap Topography Layer, each feature is a record in a database. Each of these records has information about the feature’s position and shape on Earth – its geometry – as well as details about it termed ‘attributes’. It provides an accurate visual context to help you interpret addresses, routes and imagery provided by the other layers.

Try this product with free sample data

Give it a try

Download a small area of OS MasterMap Topography Layer.

Or try out the real thing by applying for a Data Exploration Licence

Need more technical information?

Read product guides, technical specification and further documents and support.

OS MasterMap Topography Layer

Technical information

© Crown copyright and database rights. Ordnance Survey 2024


Use cases

The user may use the Topography Layer in a wide variety of ways, including:

  • improving a user’s data capture processes and the accuracy of a user’s own derived data
  • aiding the visual clarity of data and the visual interpretation of data
  • achieving consistency and maintainable standards within geographic data holdings
  • enhancing the queries that can be run on their data and so providing better information for decision making
  • establishing a common reference between a user’s own datasets and data they may wish to share with other organisations
  • using the products in an integrated manner to derive additional information
  • identifying and managing change in their area of interest
  • creating historical views of their area of interest

A common use for the product is by organisations who have their own GI and wish to examine it in relation to the real world around them. An example would be utility companies that have assets both at surface and below surface level. They frequently need to visit these assets, either for repair, maintenance or to add new assets. By viewing their infrastructure against the features in OS MasterMap Topography Layer, it will help their crews locate the assets, become familiar with the area before they leave their depot and allow them to provide a better user service by identifying those nearby premises that need to be notified about the works.

  • Download
Data theme
  • Buildings
  • Land
  • Land Use
  • Structures
  • Transport
  • Water
  • Administrative and Statistical Units
Data structure
Vector - Identifiers
Great Britain
1:1250 to 1:10,000
  • GML 2.1.2
  • GeoPackage
  • Vector Tiles
Ordering area
  • All of Great Britain or customisable area (5km2 tiles or user defined polygon)
OS Data Hub plan
  • Premium Plan
  • Public Sector Plan

Documents and Support

Getting started guides

  • OS MasterMap Topography Layer - Overview
    The overview introduces the product and gives context for all users. It highlights key features, provides examples of potential uses for the product and lists details like file sizes, supply formats, etc.
    897 kb
    March 27, 2023
  • OS MasterMap Topography Layer - Getting started guide
    The getting started guide provides instructions for using the product in different software applications. Users with limited technical knowledge will be able to follow this guide.
    3.3 mb
    February 10, 2023
  • Getting started with GeoPackage
    This guide helps you to get started using GeoPackage - a lightweight format that can contain large amounts of complex data in a single, easy to distribute and ready to use file.
    1.11 mb
    September 30, 2021
  • Getting started with vector tiles
    This guide will help you to get started using vector tiles (MBTiles) – lightweight tiles that are efficient and quick to render in your software, letting you create customised, high-resolution, beautiful mapping.
    845 kb
    September 23, 2022

Technical specification

Supporting documents

Release notes

Additional information

The need for a national topographic dataset

OS MasterMap Topography Layer was developed in response to the need for a national topographic dataset that offers users a more sophisticated type of data that represented the world in a more realistic way and was more aligned to the increasing use and functionality of GIS and spatial technology with organisations.

The advantages of TOIDs as a referencing system

Every feature within OS MasterMap has a TOID (TOpographic IDentifier) as the unique reference. This makes it possible to identify any single feature within the dataset with no ambiguity.

Alternative referencing systems can be subject to interpretation between organisations and users, leading to challenges in accurately matching data when exchanging information with others. TOIDs provide a persistent reference throughout a features lifecycle; even if a feature undergoes change the TOID remains the same. This allows customers to link their own data and track change over time.

Having unique references is essential to making the most out of storing data within a national data repository, as these rely on unique referencing to be able to store, sort, manage, query and retrieve data efficiently.

Types of real-world objects represented in the Topography Layer

Please see our real-world object catalogue (PDF). It lists every type of real-world object in the OS MasterMap Topography Layer specification, and details how it is represented by Topography Layer features.

Accuracy of OS Mastermap Topography Layer

We define accuracy in three ways:

  • Absolute accuracy – how closely the coordinates of a point in the dataset agree with the coordinates of the same point on the ground (in the British National Grid reference system).
  • Relative accuracy – positional consistency of a data point or feature in relation to other local data points or features within the same or another reference dataset.
  • Geometric fidelity – the ‘trueness’ of features to the shapes and alignments of the objects they represent when testing the data according to the dataset specification against the ‘real world’ or reference dataset.

Available scales for OS MasterMap Topography Layer data

For cartographic representation, OS MasterMap Topography Layer is captured and designed for display at 1:1250, 1:2500 and 1:10 000 scales in urban, rural and mountain/moorland areas respectively.

In GIS OS MasterMap can be viewed over a considerable range of scales. The most scale-sensitive feature types, such as cartographic text and symbol features, are fixed in size and rapidly become less clear at smaller display scales (that is, when zoomed out).

OS MasterMap Topography Layer is also suitable for use in non–cartographic applications where the concept of scale is less applicable.

OS MasterMap revision policy

Read information about our policy for updating large-scale data, directly affecting OS MasterMap Topography Layer. Learn how we prioritise revision activity, and view the currency, definition, and criteria of categories of change.

View the OS MasterMap revision policy

OS MasterMap Topography Layer

Get this product

What you get

Key features
  • Mapping from the ground up
  • Accurate referencing
  • Enhanced features
  • The foundation of the OS MasterMap family
  • Download
Data structure
Vector - Identifiers
Update frequency
Every six weeks

Try this product with free sample data

Give it a try

Download a small area of OS MasterMap Topography Layer.

Or try out the real thing by applying for a Data Exploration Licence

How to access


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