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Our public task

Understand what we're here to do.

Ordnance Survey (OS) is Great Britain’s mapping agency. We create, maintain and disseminate consistent, definitive and authoritative geospatial and cartographic data and products of Great Britain in the national interest.

With effect from 1 April 2015 we have operated as a Government owned limited company, the entire issued share capital of which is held by the Secretary of State for Business, Energy and Industrial Strategy.

This statement describes our current Public Task for the purposes of the Re-Use of Public Sector Information Regulations 2015 (the Re-use Regulations).

Our Public Task

  • We maintain and develop the underlying physical infrastructure which is needed to support mapping applications; including to maintain a national grid and the national geodetic and height frameworks and to link these to international systems.
  • We create, maintain and provide governance for the National Geographic Database (NGD) made up of geographic information datasets with coverage of all of Great Britain to a consistent specification.
  • We make the content of the relevant datasets widely available as products which can be used by customers of all types for a wide range of purposes.
  • We provide advice and support to the UK Government on all aspects of survey, mapping and geographic information (e.g. in relation to national security issues and provision of the mapping for emergency services).

In order to deliver our Public Task we collect and record the following information:

  • The topography and topology of natural and man-made features of the landscape.
  • Descriptive annotations and distinctive names/postal numbers of buildings, places and features.
  • The connectivity of water and communication networks including the routing attribution of road, tracks and paths.
  • The alignment of administrative and electoral boundaries.
  • The extent and classification of certain types of land cover and use.

The Ordnance Survey Act 1841 provides powers to enable the collection of this information.

Published on 1 February 2016.

Public Task Dataset

Brief description of Dataset

Products currently produced from the Dataset which are within the Public Task




Precise Positioning Data

A dataset of real time readings taken from a network of permanent GNSS receivers across Great Britain. The combined data is used to generate corrections that enable precise positions to be defined by a GNSS roving receiver.

OS Net services


Content and unique identifiers regarding the topography of Great Britain, ‘topography’ meaning the surface, shape and composition of the landscape, comprising both natural and artificial features. Constitutes the only nationally topologically consistent, fully maintained and authoritative large scale topographic data available for the whole of Great Britain.


Populated directly from surveys collected at precisions and root mean square error accuracy (RMSE) of:

-          Urban areas 0.4m

-          Rural areas 1.1m

-          Mountain and moorland 4.2m

OS MasterMap® Topography Layer

Communications networks

Authoritative, geometrically precise and nationally consistent large scale communications (road, track and path) network data together with traffic flow, height and weight restriction attributes for all of Great Britain. The dataset comprises:

-          Roads network data

-          Urban Path network data

OS MasterMap®

Integrated Transport Network layer

OS MasterMap® Networks – Water Layer

OS Open Rivers

OS Open Roads


Authoritative and fully maintained database of precisely grid referenced addresses providing consistently attributed detailed data for the whole of Great Britain, and forming the core addressing content of NGD, and containing Land and Property Address Data.


AddressBase™ Plus

AddressBase™ Premium


OS MasterMap Address Layer

OS MasterMap Address Layer 2


Code-Point with Polygons

Code-Point Open

OS Locator

1:50 000 Scale Gazetteer

OS Open Names

National Height data

The Integrated Digital Terrain Model (iDTM) contains information about the terrain and features of Great Britain. It is an authoritative and nationally consistent dataset stored and maintained in three dimensions as a Triangulated Irregular Network (TIN).


The model is accurate to RMSE of 1.5m in urban areas, and 2.5m in rural areas and mountainous and moorland regions.


The height model has been interrogated to output digital terrain models (bare earth) at two resolutions with horizontal resolutions of 5 metres and 50 metres respectively.

OS Terrain 5

OS Terrain 50

Administrative Boundaries

The authoritative reference dataset of administrative area polygons complementing other formal management (e.g. health service; utility services) and statistical analysis areas.


The data is derived from the surveyed alignments and Boundary Order attribution contained within the NGD Topography, and presented at a resolution commensurate with a nominal scale of 1:10 000, comprising:


European and UK Parliamentary Constituency Boundaries within Great Britain;

National Boundaries within Great Britain; and

Local Authority administration boundaries.


Mid-Scales Databases


Datasets derived from the large scale topographic database using nationally consistent generalisation rules.

OS VectorMap Local Vector

OS VectorMap Local Raster

OS StreetView

OS VectorMap District Vector

OS VectorMap District Raster

1:25,000 Scale Colour Raster

OS Open Map Local

OS Explorer Map series

1:50,000 Scale Height data


A database of contours created from height elements depicted in the OS Landranger 1:50 000 scale map series. These were originally generated from stereo aerial photography flown during the 1970s.


Contours: 10m vertical interval – national cover with an accuracy of 3.0m RMSE; and

Digital Terrain Model with a 50m horizontal rectangular grid.

Land-Form PANORAMA® Contours


Small-Scales Vector database


A multi-sourced geographical reference dataset at a nominal scale of circa 1:50 000.



1:250 000 Scale Database


Consistent national small scales database of communications, settlements, major hydrology and significant vegetation providing selected topographic information at the regional level.


1:250,000 Scale Colour Raster

Administrative Boundary Maps

1:1 000 000 dataset


A simple graphical dataset of Great Britain with geographical and topographical content appropriate to a small scales national geographical overview map.