# 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](https://docs.os.uk/osngd/data-and-service-status/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](https://www.ordnancesurvey.co.uk/contact-us/business-government/use-os-data).

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Any live interruptions to the availability of OS NGD API – Features and OS NGD API – Tiles will be documented on the [Service Availability Dashboard on the OS Data Hub](https://osdatahub.os.uk/support/status).
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## Generic OS NGD current known data issues

The generic data issue in the table below impacts multiple OS NGD themes:

<table data-full-width="true"><thead><tr><th width="284">Data Issue Name</th><th width="639.066650390625">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Very small number of features not being given the correct 'End of Life' change type</td><td>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.</td><td>29/09/2022</td></tr></tbody></table>

## OS NGD Address Theme current known data issues

<table data-full-width="true"><thead><tr><th width="283.199951171875">Data Issue Name</th><th width="644.266845703125">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Small numbers of UPRNs appearing across lifecycle feature types in COUs</td><td><p>We are aware of an issue that affected the OS NGD Address Theme during February and March 2026, where a small number of Unique Property Reference Numbers are appearing in more than one lifecycle feature type (i.e. present in both the Built Address Feature Type and the Pre‑Build Address Feature Type). This issue may affect customers who received either Full Supply or Change-Only Update (COU) orders containing OS NGD Address feature types across data schema versions 1.0, 2.0 or 3.0 during that time. If you believe you are affected by this issue, please <a href="https://www.ordnancesurvey.co.uk/contact-us/business-government/use-os-data">contact us for assistance</a>.</p><p> </p><p>This issue is distinct but related to a similar issue reported and resolved within February.</p></td><td>06/03/2026</td></tr><tr><td>Incorrect change type for addresses moving between feature types</td><td><p>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.</p><p><br>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'. </p><p></p><p>This issue impacts OS NGD Address feature types in both data schema versions (i.e. data schema versions 1.0 and 2.0).</p><p><br>Your COU processing will still work correctly, and your data holdings will be complete, but the address will have been incorrectly marked as 'New'. </p></td><td>May 2023</td></tr></tbody></table>

## OS NGD Administrative and Statistical Units Theme current known data issues

<table data-full-width="true"><thead><tr><th width="283">Data Issue Name</th><th width="646.4666748046875">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Retail Hierarchy attribute values not as expected in places</td><td>In a small number of cases for Retail Area Aggregated features (data schema version 1.0), published <a href="../../data-structure/administrative-and-statistical-units/functional-areas/retail-area-aggregated#retailhierarchy">Retail Hierarchy attribute</a> values are incorrect and appear to be demotions. For example, an expected Town Centre could be published with a Retail Hierarchy attribute value of Small Town Centre. We are investigating the cause of this error, and any improvements will be made available as part of the regular releases of OS Functional Areas Collection data. The Retail Hierarchy attribute is available for Retail Area Aggregated features only.</td><td>26/03/2026</td></tr><tr><td>Historic European Region Feature Type</td><td>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.<br><br><strong>Update on 26/02/2026</strong>: A fix has been implemented and should be present for the May 2026 release of data for the OS Boundaries Collection. </td><td>08/07/2024</td></tr></tbody></table>

## OS NGD Buildings Theme current known data issues

<table data-full-width="true"><thead><tr><th width="285">Data Issue Name</th><th width="644.533203125">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Incorrect building height values for some multi-storey properties with a single storey annexe</td><td>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.<br><br>This impacts data schema version 4.0 onward of the Building Feature Type.</td><td>27/03/2025</td></tr><tr><td>Minor confusion between roofs of similar appearance</td><td><p>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. </p><p></p><p>This is something we aim to address in future iterations of roof type data for the Building Feature Type.<br><br>This impacts data schema version 4.0 onward of the Building Feature Type.</p></td><td>27/03/2025</td></tr><tr><td>Inconsistent caravan roof shape</td><td><p>Large static caravans will have inconsistent roof shapes due to the shallow-pitched nature of their roofs, making it difficult to ascertain true shape.</p><p><br>This impacts data schema version 4.0 onward of the Building Feature Type.</p></td><td>27/03/2025</td></tr><tr><td>Additional in-scope buildings included in the Number of Floors data</td><td><p>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.</p><p><br>This impacts data schema versions 3.0 and 4.0 onward of the Building Feature Type.</p></td><td>25/09/2024</td></tr><tr><td>Some in-scope residential buildings are excluded from the Number of Floors data</td><td><p>Some in-scope residential buildings have no values for the Number of Floors attributes (for example, new builds, and buildings failing height validation rules).</p><p><br>This impacts data schema versions 3.0 and 4.0 onward of the Building Feature Type.</p></td><td>25/09/2024</td></tr><tr><td>Some apartment block buildings are excluded from the Number of Floors data</td><td><p>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.</p><p><br>This impacts data schema versions 3.0 and 4.0 onward of the Building Feature Type.</p></td><td>25/09/2024</td></tr></tbody></table>

## OS Geographical Names Theme current known data issues&#x20;

<table data-full-width="true"><thead><tr><th width="285">Data Issue Name</th><th width="651.7333984375">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Poor linking between Crowd Sourced Name Point features and other OS NGD features</td><td>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).</td><td>27/03/2025</td></tr></tbody></table>

## OS NGD Land Theme current known data issues&#x20;

<table data-full-width="true"><thead><tr><th width="285">Data Issue Name</th><th width="656.6668701171875">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Nullified Access Purpose attribute for certain Site Access Location features</td><td>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).</td><td>27/03/2025</td></tr></tbody></table>

## OS NGD Land Use Theme current known data issues

No current known data issues to note for this theme.

## OS NGD Structures Theme current known data issues

<table data-full-width="true"><thead><tr><th width="286">Data Issue Name</th><th width="664.7335205078125">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Completeness for bridge interactions</td><td>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 onward), the attributes will not be populated (i.e. will be ‘null’).</td><td>25/09/2024</td></tr><tr><td>Mersey Railway Tunnels and Westferry Circus Tunnel missing</td><td>The Mersey Railway Tunnels and Westferry Circus Tunnel are not included in data schema v2.0 onward of the Compound Structure Feature Type.</td><td>25/09/2024</td></tr><tr><td>Overlapping of stacked bridges</td><td>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 onward). </td><td>25/09/2024</td></tr><tr><td><p>Overlapping Field Boundary</p><p>features exist</p></td><td>Approximately 20 000 Field Boundary Feature Type features (data schema version 1.0) are overlapping. This issue is currently being investigated.</td><td>27/03/2024</td></tr></tbody></table>

## OS NGD Transport Theme current known data issues

<table data-full-width="true"><thead><tr><th width="289.9998779296875">Data Issue Name</th><th width="658.5999755859375">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Restriction referencing errors</td><td>6 Restriction features (data schema version 1.0) reference non-existent Road Link (data schema versions 2.0, 3.0, 4.0 and 5.0) features. This issue is currently being investigated</td><td>01/02/2026</td></tr><tr><td>Highway Dedication to Network Feature cross reference table refers to non-existent features.</td><td>14 records in the Highway Dedication to Network Feature cross reference table reference Road Link (data schema versions 2.0, 3.0, 4.0 and 5.0) features which do not exist. 113 records reference Path Link (data schema versions 1.0, 2.0, 3.0) features which do not exist and 17 records reference Street (data schema version 1.0) features which do not exist. This issue is currently being investigated.</td><td>01/02/2026</td></tr><tr><td>Incorrect modal or minimum width values for Cycle Lane features</td><td>There are 85 Cycle Lane features (data schema version 1.0) that have a modal and minimum width values of 0m (Cycle Lane Info Modal Width M, and Cycle Lane Info Minimum Width M attributes).</td><td>25/09/2025</td></tr><tr><td>Incorrect evidence dates for Cycle Lane features</td><td>There are 24 Cycle Lane features (data schema version 1.0) with an incorrect Geometry Evidence Date attribute date value of 01-01-2000.</td><td>25/09/2025</td></tr><tr><td>Superfluous Road and Path Nodes</td><td>92 superfluous Road Nodes and 400 Path Nodes are unexpectedly present in OS NGD Transport Networks. These nodes are not referenced by any existing links. This issue is currently being investigated.</td><td>24/09/2025</td></tr><tr><td>Missing records in Street to Road Link cross reference table</td><td>Approximately 110 000 Road Links with a Match Status of 'Matched' do not appear in trn_ntwk_street_rdlinkref as expected.</td><td>01/05/2025</td></tr><tr><td>Rail Network referencing errors</td><td>2 Railway Link features (data schema version 1.0) are not connected to a Railway Node feature (data schema version 1.0) at one or both ends, and 97 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.</td><td>01/03/2025</td></tr><tr><td>Unexpected references for Street features in the Highway Dedication Network Reference cross reference table</td><td>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), there are 378 instances of the Network Reference ID attribute referencing a USRN which does not exist. This issue is currently being investigated.</td><td>24/05/2024</td></tr><tr><td>Mismatches between Road Link Directionality attribution and Average Speed attribution</td><td>There are 971 Road Link features (data schema versions 1.0, 2.0, 3.0, 4.0 and 5.0) 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.</td><td>01/04/2024</td></tr><tr><td>Street to Path Link reference table refers to non-existent features</td><td>19 records in the Street to Path Link reference table refer to Path Link features which no longer exist. This issue is currently being investigated.</td><td>01/03/2024</td></tr><tr><td>Referencing errors in the Road and Path Network</td><td><p>2 Road Link features (data schema versions 2.0, 3.0, 4.0 and 5.0) reference non-existent Road Node (data schema version 1.0) features. <br></p><p>17 Road features (data schema version 1.0) reference non-existent Road Link (data schema versions 1.0, 2.0, 3.0, 4.0 and 5.0) features.</p><p></p><p>4 Path features (data schema version 1.0) reference non-existent Path Link (data schema versions 1.0, 2.0 and 3.0) features.<br></p><p>130 Connecting Link features (data schema version 1.0) reference non-existent Connecting Node (data schema version 1.0) features and 1 Connecting Link feature (data schema version 1.0) references a non-existent Road Node feature (data schema version 1.0).<br></p><p>These issues are currently being investigated.</p></td><td>01/09/2023</td></tr><tr><td>Feature Count discrepancies compared to OS MasterMap Highways Network</td><td>A small number of features in the following feature types are missing when compared to the comparable tables in OS MasterMap Highways Network: Connecting Node (data schema version 1.0), Highway Dedication (data schema version 1.0), Maintenance feature types (data schema version 1.0), Path Link (data schema versions 1.0, 2.0 and 3.0), Path Node (data schema version 1.0), Reinstatement feature types (data schema version 1.0), Restriction (data schema version 1.0), Road Node (data schema version 1.0), Routing Hazard (data schema version 1.0), Special Designation feature types (data schema version 1.0) and Street (data schema version 1.0). This issue is currently being investigated.</td><td>14/08/2023</td></tr></tbody></table>

## OS NGD Water Theme current known data issues

<table data-full-width="true"><thead><tr><th width="291.7333984375">Data Issue Name</th><th width="652.2666015625">Data Issue Description</th><th>Data Issue Identification Date</th></tr></thead><tbody><tr><td>Unexpectedly high maximum width values for Water Links</td><td>There are a small number of Water Link features (data schema version 2.0) that have unexpectedly high Width Maximum attribute values.</td><td>30/10/2025</td></tr><tr><td>Unexpected Width Derivation Method for Water Links</td><td>There are 158 Water Link features (data schema version 2.0) that have been assigned a Width Average attribute value based on a 'Default Value For Geographic Region', when they are expected to receive a Width Average attribute value that is derived either from 'Modelled From Network' or 'Calculated from Polygon'.</td><td>30/10/2025</td></tr><tr><td>Invalid geometries in Waterbody Catchment and River Basin District Catchment features</td><td>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.</td><td>28/03/2023</td></tr><tr><td>Incorrect representation of a Waterbody Catchment name</td><td>The Barlings Eau Upper catchment name is incorrectly displayed. This is as per the third-party data from the authoritative bodies.</td><td>28/03/2023</td></tr><tr><td>Non-unique Waterbody Catchment IDs</td><td>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.</td><td>28/03/2023</td></tr><tr><td>Certain Waterbody Catchment features do not nest exactly within a River Basin District Catchment</td><td>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.</td><td>28/03/2023</td></tr></tbody></table>