Current Known Data Issues
This page lists known current live data issues in relation to the OS National Geographic Database (NGD) themes, collections and feature types.
As and when we resolve a known data issue, we will move it to the Resolved Data Issues page. To report an issue that's not currently listed on these pages, please use the 'Contact us' section of the OS website.
Generic OS NGD current known data issues
The generic data issue in the table below impacts multiple OS NGD themes:
Very small number of features not being given the correct 'End of Life' change type
There are 319 features (out of 600+ million) which reside within the 'features' collections (i.e. any OS NGD collection which has a name of 'OS NGD XXX Features', for example, OS NGD Transport Features) that have not been given the correct 'End of Life' change type. This means that these features still reside within the supply but should be deleted.
29/09/2022
OS NGD Address Theme current known data issues
Incorrect change type for addresses moving between feature types
In a very small number of cases, when an address moves between feature types, such as moving from Pre-Build Address to Built Address, the change type given is incorrect.
The address 'leaving' the Pre-Build Address Feature Type is correctly marked 'Moved To', but when it enters the Built Address Feature Type, it is incorrectly marked as 'New' rather than 'Moved From'.
This issue impacts address feature types in both data schema versions (i.e. data schema versions 1.0 and 2.0).
Your Change-Only Update (COU) processing will still work correctly, and your data holdings will be complete, but the address will have been incorrectly marked as 'New'.
May 2023
OS NGD Administrative and Statistical Units Theme current known data issues
Three missing parishes from the Parish Or Community Feature Type
The Margaret March, Tollard Royal and Marlow Bottom Civil Parish (CP) within the Parish Or Community Feature Type (data schema version 1.0) are missing from the current (May 2025) release of data.
This issue is currently being investigated and we are working to fix it for a future release.
July 2024
Historic European Region Feature Type
This feature type (data schema version 1.0) contains updates made to the boundaries post 01 April 2021 (when the feature type was frozen in the Boundary-Line product). This means that there will be differences between the boundaries accessed via our OS OpenData pages and those accessed via OS NGD.
08/07/2024
OS NGD Buildings Theme current known data issues
Incorrect building height values for some multi-storey properties with a single storey annexe
Some residential two-storey properties with a large adjoining single storey are returning as a single storey when created using machine learning (due to incorrect building height values), for example, two-storey houses with attached garages or large rear extensions.
TBC
Minor confusion between roofs of similar appearance
When capturing roof type data through our aerial capture program, there can be some confusion between buildings with glass roofs or an evacuated tube collector and those with solar panels present. As a result, buildings with glass roofs may be incorrectly attributed with solar panel presence.
This is something we aim to address in future iterations of roof type data for the Building Feature Type.
27/03/2025
Inconsistent caravan roof shape
Large static caravans will have inconsistent roof shapes due to the shallow-pitched nature of their roofs, making it difficult to ascertain true shape.
27/03/2025
Additional in-scope buildings included in the Number of Floors data
Some notable non-residential and non-office buildings that meet the scope will be included (for example, several cathedrals and arenas) and will have values for the Number of Floors attributes.
25/09/2024
Some in-scope residential buildings are excluded from the Number of Floors data
Some in-scope residential buildings have no values for the Number of Floors attributes (for example, new builds, and buildings failing height validation rules).
25/09/2024
Some apartment block buildings are excluded from the Number of Floors data
Apartment blocks that have their address geometry situated in the stairwell of the building and have their building geometry segregated due to the Land Use Site Feature Type will not get values for the Number of Floors attributes.
25/09/2024
OS Geographical Names Theme current known data issues
Poor linking between Crowd Sourced Name Point features and other OS NGD features
We are actively improving the linking between Crowd Sourced Name Point features (data schema version 1.0) and other OS NGD features, so some updates are expected; these updates will be delivered through standard change-only updates (COUs).
27/03/2025
OS NGD Land Theme current known data issues
Nullified Access Purpose attribute for certain Site Access Location features
Some key public sites have refused access to surveyors and so will have their Access Purpose attribute nullified for the Site Access Location feature (data schema version 2.0 only as this attribute is not available for data schema version 1.0).
27/03/2025
OS NGD Land Use Theme current known data issues
Uppercase and lowercase variations of two description values in Site Feature Type data schema v1.2
Two description values in data schema v1.2 of the Site Feature Type contain duplicates with uppercase and lowercase variations. Data schema v1.0 of Site was launched incorrectly with two description values that did not align with OS casing standards, and on 25 September 2024 the data and related code list were updated to fix this issue.
The two affected values are:
Education Support Site
Public Waste Disposal Site
The OS NGD access services of OS NGD API – Features and OS Select+Build validate against the data schema, meaning both versions of the description values must be retained to facilitate filtering.
The lowercase values (i.e. Education Support site and Public Waste Disposal site) should be used to filter and retrieve historical features (before 25/09/24), while the uppercase values (i.e. Education Support Site and Public Waste Disposal Site) should be used for records after this date.
This issue only affects data schema version 1.2 of Site; data schema v2.0 of Site was launched with the casing standards consistently applied.
November 2023
OS NGD Structures Theme current known data issues
Duplicate features in the OS NGD Structures and OS NGD Land Themes, and duplicate features in OS NGD Structures and OS NGD Building Themes
Following a recent update, not all features which were due to move themes fully migrated from one OS NGD theme to another. There are 3 595 duplicate features in the below themes:
3 584 ‘slipway’ features are in both the OS NGD Structures Theme and the OS NGD Land Theme. These features should only be available in the OS NGD Land theme.
11 ‘Grandstand’ features are in both the OS NGD Structures Theme and the OS NGD Buildings Theme. These features should only be available in the OS NGD Building Part Feature Type.
The duplicated features have the same ID when represented in the more than one Feature Type.
This duplication is present in OS NGD Structure Feature Type data schema v1.0, v2.0 and v3.1.
29/07/2025
Temporal differences to data currency for bridge interactions
Bridges in the OS NGD Structure Features Collection are updated daily, whereas networks in the OS NGD Transport Network Collection and the OS NGD Water Network Collection are updated monthly and quarterly, respectively.
25/09/2024
Completeness for bridge interactions
On rare occasions where Network Over and Network Under attribution cannot be identified (i.e. disused bridges or viaducts over dry valleys) for Compound Structure Feature Type features (data schema version 2.0), the attributes will not be populated (i.e. will be ‘null’).
25/09/2024
Overlapping of stacked bridges
Where bridges cross one other, it can be difficult to identify the correct networks running over and / or under each bridge. This impacts Compound Structure Feature Type features (data schema version 2.0).
25/09/2024
Mersey Railway Tunnels and Westferry Circus Tunnel missing
The Mersey Railway Tunnels and Westferry Circus Tunnel are not included in the initial release of data schema v2.0 of the Compound Structure Feature Type.
TBC
Some underground Structure features are missing from the Habitat Coverage cross reference table
Three underground Structure features with an OS Land Cover Tier B attribute of ‘Coniferous Trees’, ‘Non-Coniferous Trees’, ‘Scattered Coniferous Trees’ or ‘Scattered Non-Coniferous Trees’ are missing from the corresponding Habitat Coverage Reference cross reference table. This issue impacts the Land Feature Type.
15/04/2024
Overlapping Field Boundary
features exist
Approximately 20 000 Field Boundary Feature Type features (data schema version 1.0) are overlapping. This issue is currently being investigated.
27/03/2024
Field Boundary data quality
At the time of launch of the Field Boundary Feature Type (March 2024; data schema version 1.0), areas of Great Britain were still to be quality checked and will be improved as part of OS’s continuous quality review programme when updated imagery is available. Most of the known data quality errors are either in Moorland areas or where imagery was captured earlier in the year and vegetated features are ‘leaf-off’. The downloadable file below (last updated in August 2024) contains the status of each 10km² area relating to the quality of the Field Boundary feature classification.
27/03/2024
OS NGD Transport Theme current known data issues
Unexpected Effective Start Date or Effective End Date attributes in Street and RAMI Collection tables
Effective Start Date and Effective End Date attributes are not being populated as expected in some Street, Maintenance Area, Maintenance Line, Maintenance Point, Reinstatement Area, Reinstatement Line, Reinstatement Point and Highway Dedication features (data schema version 1.0).
29/05/2025
Missing records in Street to Road Link cross reference table
Approximately 900,000 Road Links with a Match Status of 'Matched' do not appear in trn_ntwk_street_rdlinkref as expected.
01/05/2025
Rail Network referencing errors
1 Railway Link feature (data schema version 1.0; OSID of e14ea5cf-0d9c-4417-884d-16604d5b3208) is not connected to a Railway Node feature (data schema version 1.0) at one or both ends, and 100 Railway Node features (data schema version 1.0) are not coincident with the start or end of the Railway Link features (data schema version 1.0) that reference them. This issue is currently being investigated.
01/03/2025
Road Links with unexpected pavement update dates
76 Road Link features (data schema versions 2.0, 3.0 and 4.0) with an incorrect Presence of Pavement Update Date attribute date value in the future (2999). The update date should reflect when the attribute was last updated, so it should never be a future date. This issue is currently being investigated.
01/05/2024
Mismatches between Road Link Directionality attribution and Average Speed attribution
There are 2 307 Road Link features (data schema versions 1.0, 2.0, 3.0 and 4.0) where the Directionality attribution of the Road Link and the attribution describing average speeds are not in sympathy (for example, the Road Link is in Both Directions, but average speed attribution is only available for one of the directions). Some instances of this are a result of the Road Network being updated monthly and speed information being updated six-monthly; however, the remaining instances where this does not apply are being investigated.
01/04/2024
Road Links with unexpected 0 values for pavement width attributes
212 Road Link features (data schema versions 2.0, 3.0 and 4.0) where we would expect their Presence of Pavement Minimum Width M and Presence of Pavement Average Width M attributes to be populated have a value of 0 for these attributes. This issue is currently being investigated.
01/04/2024
Unexpected references for Street features in the Highway Dedication Network Reference cross reference table
Where the Highway Dedication Network Reference cross reference table (used by Highway Dedication features, data schema v1.0) references a Street feature (data schema version 1.0), the Network Reference ID attribute is populated with an OSID rather than a USRN as is expected for Street features. This issue is currently being investigated.
01/03/2024
Street to Road Link and Street to Path Link reference tables refer to non-existent features
3 919 records in the Street to Road Link reference table and 1 184 records in the Street to Path Link reference table refer to Road Link or Path Link features which no longer exist. This issue is currently being investigated.
01/03/2024
Small number of referencing errors in the Road and Path Network
1 Road Link feature (data schema version 4.0), 3 Path Link features (data schema version 2.0), and 17 Connecting Link features (data schema version 1.0) reference non-existent Road Node features (data schema version 1.0), Path Node features (data schema version 1.0), or Connecting Node features (data schema version 1.0), and 2 Path Node features (data schema version 1.0) are unreferenced by any existing Path Link features. This issue is currently being investigated.
01/09/2023
OS NGD Water Theme current known data issues
Unexpectedly null Level of Detail values for Water Links
4 065 Water Link features (data schema version 1.0) incorrectly have a null Level of Detail attribute value. All Water Links should have this value populated. This issue is currently being investigated.
05/10/2023
Unexpectedly null Catchment Name and Catchment ID for Water Links
Approximately 19 000 Water Link features (data schema version 1.0) incorrectly have a null Catchment Name and Catchment ID. Only links which straddle catchment boundaries or sit entirely outside catchments should have null values in these attributes. This issue is currently being investigated.
03/10/2023
Unexpected Water Link names
Approximately 4 000 Water Link features (data schema version 1.0) are not being named as expected: Name 1 Text / Name 2 Text attribute populated with the name from the longest (by length) named waterway; Name Secondary 1 Text attribute populated with the name of the next longest named waterway, etc. This issue is currently being investigated.
24/07/2023
Water Link features with an End Node attribute value of 'MissingXRef'
3 667 Water Link features (data schema version 1.0) erroneously have an End Node attribute value of 'MissingXRef'. This may cause problems with validation as the value is not a valid OSID. This issue is currently being investigated.
04/04/2023
Orphaned Water Nodes
1 007 Water Node features (data schema version 1.0) are not referenced by any extant Water Link. This issue is currently being investigated.
01/07/2025
Invalid geometries in Waterbody Catchment and River Basin District Catchment features
Some polygons for Waterbody Catchment and River Basin District Catchment features (data schema version 1.0) have invalid geometries in the form of self-intersections, holes, and gaps. Instances of self-intersection are primarily due to the gridded digital terrain model (DTM) used to generate the catchment data provided by the third-party data from authoritative bodies.
28/03/2023
Incorrect representation of a Waterbody Catchment name
The Barlings Eau Upper catchment name is incorrectly displayed. This is as per the third-party data from the authoritative bodies.
28/03/2023
Non-unique Waterbody Catchment IDs
Two instances occur where the Waterbody Catchment ID is not unique for Waterbody Catchment features (data schema version 1.0): GB109056040082 and GB104027063230. This is as per the third-party data from the authoritative bodies.
28/03/2023
Certain Waterbody Catchment features do not nest exactly within a River Basin District Catchment
A total of 14 instances occur where Waterbody Catchment features (data schema version 1.0) do not nest exactly within their associated River Basin District Catchment features (data schema version 1.0). This is as per the third-party data from the authoritative bodies.
28/03/2023
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