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.
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.
The OS NGD is in its infancy and, as such, will be largely developed and iterated upon in its early life.
Generic OS NGD current known data issues
The generic data issues in the table below impact multiple OS NGD themes:
Interruption to the supply of Daily Updates for OS NGD Building Part (February 2025) and impact on topological data ‘surface’ of OS NGD 'Feature' Collections
We are currently deploying improvements to the Building Height data available on OS NGD Building Part (data schema v1.0 and v2.0) until 24 February 2025. During this period, daily updates to the Building Part Feature Type, such as changes captured by surveyors, will be temporarily paused. These changes will be reflected in the product data after the completion of the improvements.
Consequently, users may observe anomalies in the consistency of the topological surface when utilising various OS NGD 'Feature' Collections (such as OS NGD Land Features). These anomalies will manifest as holes or overlaps where the Building Part feature has not been updated concurrently with the surrounding features. This impact will also be visible in OS NGD API – Features and OS NGD API – Tiles.
Please note that we advise against using counts from the OS NGD Building Part Feature Type with a temporal filter set between 02 February 2025 and 24 February 2025 as the counts may not be accurate due to the impact on a small number of topographic features.
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 'XXX Features', for example, 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.
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'.
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'.
OS NGD Administrative and Statistical Units Theme current known data issues
Historic European Region Feature Type
This feature type 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.
Three Missing Parishes from the 'Parish or Community' Layer
The Margaret March, Tollard Royal and Marlow Bottom Civil Parish (CP) within the Parish or Community layer is missing from the current (October 2024) release of data. This issue is currently being investigated and we are working to fix it for a future release.
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.
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).
Some in-scope residential buildings are excluded from the Number of Floors data
Some in-scope residential buildings have no Number of Floors value (for example, new builds, and buildings failing height validation rules).
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 a Number of Floors value.
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 Buildings Feature Type.
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.
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 and other OS NGD features, so some updates are expected; these updates will be delivered through standard change-only updates (COUs).
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.
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.
OS NGD Structures Theme current known data issues
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.
Overlapping Field Boundary
features exist
Approx. 20 000 Field Boundary features are overlapping. This issue is currently being investigated.
Field Boundary data quality
At the time of launch of the Field Boundary Feature Type (March 2024), 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 contains the status of each 10km² area relating to the quality of the Field Boundary feature classification.
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.
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), the attributes will not be populated (i.e. will be ‘null’).
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.
Mersey Railway Tunnels and Westferry Circus Tunnel missing
The Mersey Railway Tunnels and Westferry Circus Tunnel are not included in the initial release of Compound Structure data schema v2.0.
OS NGD Transport Theme current known data issues
Unexpected Highway Dedication Network References to Streets
Where the Highway Dedication Network Reference references a Street feature, the Network Reference ID attribute is populated with an OSID rather than a USRN as expected for Streets. This issue is currently being investigated.
Street to Road Link and Street to Path Link reference tables refer to non-existent features
4 153 records in the Street to Road Link reference table and 1 055 records in the Street to Path Link reference table refer to Road Links or Path Links which no longer exist. This issue is currently being investigated.
Small number of referencing errors in the Road and Path Network
1 Road Link and 3 Path Links reference non-existent Road Nodes or Path Nodes, and 2 Path Nodes are unreferenced by any existing Path Link. This issue is currently being investigated.
Mismatches between Road Link directionality and Average Speed attribution
There are 854 Road Links where the directionality of the Road Link and the attribution describing average speeds are not in sympathy (for example, 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.
Rail Network referencing error
145 Railway Links are not connected to a Railway Node at one or both ends, and 188 Railway Nodes are not coincident with the start or end of the Railway Link that references them. This issue is currently being investigated.
Duplicate Street Light features
There are around 84 000 Street Light features that are duplicated in Milton Keynes, Bedford and surrounding areas. This means that in this area, each street Light geometry is replicated twice; however, each geometry will still have its own unique OSID.
We are currently working to resolve this issue.
Incorrect Street Light coverage values on Road Links
We are aware of an issue that has caused a small number of incorrect values for Street Light coverage attribution on Road Links. Impacted Road Links will have a Presence Of Street Light Coverage attribute value that does not align with the evidence of street light presence in the Street Light Feature Type.
For example, a Road Link that has Street Lights features along it may have a coverage value of 'Fully Unlit' when it does in fact have Street Light features alongside it.
This issue affects approximately 0.45% of Road Links.
We are currently working to resolve this issue.
OS NGD Water Theme current known data issues
Invalid geometries in Waterbody Catchment and River Basin District Catchment features
Some catchment polygons 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.
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.
Non-unique Waterbody Catchment IDs
Two instances occur where the Waterbody Catchment ID is not unique: GB109056040082 and GB104027063230. This is as per the third-party data from the authoritative bodies.
Certain Waterbody Catchment features do not nest exactly within a River Basin District Catchment.
A total of 14 instances occur where Waterbody Catchments do not nest exactly within their associated River Basin District Catchment. This is as per the third-party data from the authoritative bodies.
Unexpectedly null Level of Detail values for Water Links
Approximately 900 000 Water Links incorrectly have a null Level of Detail Attribute value. All Water Links should have this value populated. This issue is currently being investigated.
Unexpected Water Link names
A number of features 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.
Unexpectedly null Catchment Name and Catchment ID for Water Links
Approximately 600 000 Water Links 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.
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