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  • OS Download Products' Documentation
  • Addressing and Location
    • Addressing and Location Portfolio Information
    • AddressBase Fundamentals
      • Release Notes
        • AddressBase Products May 2025 – Epoch 118
        • AddressBase Islands May 2025 – Epoch 118
        • AddressBase Products March 2025 – Epoch 117
        • AddressBase Islands March 2025 – Epoch 117
        • AddressBase Products February 2025 – Epoch 116
        • AddressBase Islands February 2025 – Epoch 116
        • AddressBase Products December 2024 – Epoch 115
        • AddressBase Islands December 2024 – Epoch 115
        • AddressBase Products November 2024 – Epoch 114
        • AddressBase Islands November 2024 – Epoch 114
        • AddressBase Products September 2024 – Epoch 113
        • AddressBase Islands September 2024 – Epoch 113
        • AddressBase Products August 2024 – Epoch 112
        • AddressBase Islands August 2024 – Epoch 112
        • AddressBase Products June 2024 – Epoch 111
        • AddressBase Islands June 2024 – Epoch 111
        • AddressBase Products May 2024 – Epoch 110
        • AddressBase Islands May 2024 – Epoch 110
        • AddressBase Products April 2024 – Epoch 109
        • AddressBase Islands April 2024 – Epoch 109
      • AddressBase product family
      • Future and past publication dates
      • Unique Property Reference Number (UPRN)
      • Coordinate reference systems
      • Classification scheme
      • Data sources
      • Street names and numbering
      • Currency, completeness and precision
      • Product supply
      • Code lists and enumerations
        • AddressbasePostalCode
        • BLPUStateCode
        • ChangeTypeCode
        • CountryCode
        • Date
        • FileTypeCode
        • LanguageCode
        • LogicalStatusCode
        • OfficialFlagCode
        • PostcodeTypeCode
        • RPCCode
        • StateCode
        • StreetClassificationCode
        • StreetRecordTypeCode
        • StreetStateCode
        • StreetSurfaceCode
        • Time
        • USRNMatchIndicatorCode
      • AddressBase local custodian codes
      • AddressBase Islands local custodian codes
    • AddressBase
      • Release Notes
      • AddressBase Getting Started Guide
        • Prerequisites
        • Data supply
        • Working with CSV data
        • Working with GML data
        • Working with COU data
        • Creating a single-line or multi-line address
        • Searching for addresses
      • AddressBase Technical Specification
        • Data formats
        • Supply and update
        • AddressBase structure
        • Feature types
          • Address
          • AddressBase Supply Set
        • Code list and enumerations
        • CSV to GML mapping
        • Example records
          • CSV
          • GML
      • AddressBase Downloads
      • AddressBase Known Data Issues
    • AddressBase Core
      • Release Notes
        • 20 May 2025
        • 13 May 2025
        • 07 May 2025
        • 29 April 2025
        • 23 April 2025
        • 15 April 2025
        • 08 April 2025
        • 01 April 2025
        • 25 March 2025
        • 18 March 2025
      • AddressBase Core Overview
        • Data capture and sources
        • GeoPlace
        • Unique Property Reference Number (UPRN)
        • Coordinate reference systems
        • Classification
        • Currency, completeness and precision
        • Product supply
      • AddressBase Core Getting Started Guide
        • Downloading a dataset
        • Working with CSV data
        • Working with GPKG data
        • Working with COU data
        • Working with tiled data
      • AddressBase Core Technical Specification
        • Data formats
        • Supply and update
        • Attributes
        • Enumerations
        • Example records
      • AddressBase Core Downloads
      • AddressBase Core Known Data Issues
    • AddressBase Plus
      • Release Notes
      • AddressBase Plus Getting Started Guide
      • AddressBase Plus Technical Specification
        • Data formats
        • Supply and update
        • AddressBase Plus structure
        • Feature types
          • Address
          • AddressBase Supply Set
        • Code lists and enumerations
        • CSV to GML mapping
        • Example records
          • CSV
          • GML
      • AddressBase Plus Downloads
      • AddressBase Plus Known Data Issues
    • AddressBase Plus Islands
      • Release Notes
      • AddressBase Plus Islands Getting Started Guide
      • AddressBase Plus Islands Technical Specification
        • Data formats
        • Supply and update
        • AddressBase Plus Islands structure
        • Feature types
          • Address
          • AddressBase Supply Set
        • Code lists and enumerations
        • CSV to GML mapping
        • Example records
          • CSV
          • GML
      • AddressBase Plus Islands Downloads
      • AddressBase Plus Islands Known Data Issues
    • AddressBase Premium
      • Release Notes
      • AddressBase Premium Getting Started Guide
        • Prerequisites
        • Data supply
        • Working with CSV data
        • Working with GPKG data
        • Working with GML data
        • Working with COU data
        • Creating a single-line or multi-line address
        • Searching for addresses
      • AddressBase Premium Technical Specification
        • Data formats
        • Supply and update
        • AddressBase Premium structure
        • Feature types
          • Street – (Type 11 Record)
          • BLPU – (Type 21 Record)
          • AddressBase supply set
          • Feature with lifecycle
        • Structured data types
          • Street Descriptor – (Type 15 Record)
          • Application Cross Reference – (Type 23 Record)
          • LPI – (Type 24 Record)
          • Delivery Point Address – (Type 28 Record)
          • Successor Cross Reference – (Type 30 Record)
          • Organisation – (Type 31 Record)
          • Classification – (Type 32 Record)
          • Entity with lifecycle
        • Dataset metadata
          • Metadata – (Type 29 Record)
          • Header – (Type 10 Record)
          • Trailer – (Type 99 record)
        • Code lists and enumerations
        • Attribute format comparison
        • Example records
          • CSV
          • GML
      • AddressBase Premium Downloads
      • AddressBase Premium Known Data Issues
    • AddressBase Premium Islands
      • Release Notes
      • AddressBase Premium Islands Getting Started Guide
      • AddressBase Premium Islands Technical Specification
        • Release Notes
          • June 2024
        • Data formats
        • Supply and update
        • AddressBase Premium Islands structure
        • Feature types
          • Street – (Type 11 Record)
          • BLPU – (Type 21 Record)
          • AddressBase supply set
          • Feature with lifecycle
        • Structured data types
          • Street Descriptor – (Type 15 Record)
          • Application Cross Reference – (Type 23 Record)
          • LPI – (Type 24 Record)
          • Delivery Point Address – (Type 28 Record)
          • Successor Cross Reference – (Type 30 Record)
          • Organisation – (Type 31 Record)
          • Classification – (Type 32 Record)
          • Entity with lifecycle
        • Dataset metadata
          • Header – (Type 10 Record)
          • Metadata – (Type 29 Record)
          • Trailer – (Type 99 record)
        • Code lists and enumerations
        • Attribute format comparison
        • Example records
          • CSV
          • GML
      • AddressBase Premium Islands Downloads
      • AddressBase Premium Islands Known Data Issues
    • Boundary-Line
      • Release Notes
        • May 2025
        • October 2024
        • June 2024
      • Boundary-Line Overview
        • Data overview
        • Product supply
      • Boundary-Line Product Information
        • Relationships of administrative areas
        • Structure of Boundary-Line
        • Boundary-Line principles and features
        • Case studies
        • Metadata
        • Glossary
        • Exception areas
        • The coastline and associated items
      • Boundary-Line Technical Specification
        • Shapefile, TAB and GKPG
          • Features - Shapefile, TAB and GPKG
            • Area - GB
            • Area - English region
            • Area - Wales region
            • Link feature type
            • Area - Polling districts England
            • Historical and ceremonial boundaries features
          • Layers - Shapefile, TAB and GKPG
            • Shapefile
            • TAB
            • GKPG
          • Code lists - Shapefile, TAB and GKPG
            • AreaCode
            • TypeCode
        • GML
          • Features - GML
            • AdministrativeUnit
          • Code lists - GML
            • AdministrativeHierarchyValue
            • NationalClassificationValue
          • Example record - GML
        • Vector tiles
      • Guide to Ceremonial County Boundaries
      • Additional Product Details
      • Boundary-Line Downloads
      • Boundary-Line Known Data Issues
    • Code-Point
      • Code-Point Overview
        • Product details
        • Product supply
      • Code-Point Products Comparison
      • Code-Point Getting Started Guide
        • Product supply
        • Data structure
        • CSV file processing
        • Data measures
        • Metadata
        • Glossary
      • Code-Point Technical Specification
        • Product structure
        • Supply formats
      • Code-Point Downloads
      • Code-Point Known Data Issues
    • Code-Point Open
      • Code-Point Open Overview
        • Product details
        • Product supply
      • Code-Point Open Products Comparison
      • Code-Point Open Getting Started Guide
        • Requirements for using the data
        • CSV file processing
        • Data measures
        • Loading the data into a GIS
        • Glossary
      • Code-Point Open Technical Specification
        • Product structure
        • Supply formats overview
      • Code-Point Open Downloads
      • Code-Point Open Known Data Issues
    • Code-Point with Polygons
      • Release Notes
        • January 2025
      • Code-Point with Polygons Overview
        • Product details
        • Product supply
      • Code-Point with Polygons Products Comparison
      • Code-Point with Polygons Getting Started Guide
        • Using the vertical street lookup
        • Creating single-space postcodes
        • Data measures
      • Code-Point with Polygons Technical Specification
        • Data supply
        • Specification
      • Code-Point with Polygons Downloads
      • Code-Point with Polygons Known Data Issues
    • 🆕OS Emergency Services Gazetteer
      • 🆕OS ESG Overview
        • 🆕Product supply
        • 🆕Planned enhancements
      • OS ESG Getting Started Guide
      • OS ESG Technical Specification
        • Feature type
          • BLPU (Type 21 Record)
        • Structured data types
          • LPI (Type 24 Record)
          • Classification (Type 32 Record)
        • 🆕Code lists
          • AddressbasePostalCode
          • BLPUStateCode
          • ChangeTypeCode
          • 🆕ClassificationCode
          • CountryCode
          • FileTypeCode
          • LanguageCode
          • LogicalStatusCode
          • OfficialFlagCode
          • RPCCode
          • USRNMatchIndicatorCode
        • Dataset metadata
          • Header (Type 10 Record)
          • Metadata (Type 29 Record)
          • Trailer (Type 99 Record)
      • 🆕OS ESG FAQs
      • 🆕OS ESG Downloads
      • OS ESG Known Data Issues
    • OS Open Built Up Areas
      • Release notes
        • April 2024
      • OS Open Built Up Areas Overview
        • Product details
        • Product supply
      • OS Open Built Up Areas Technical Specification
        • Feature types
          • Built Up Areas
          • Built Up Extents
          • Non Built Up Extents
        • Structured data types
          • MultiSurfaceWithAreaType
          • NameType
        • Code list
          • LanguageValue
        • Supply formats
      • OS Open Built Up Areas Known Data Issues
    • OS Open Names
      • Release Notes
        • April 2025
        • January 2025
        • October 2024
        • July 2024
      • OS Open Names Overview
        • Product applications
        • Product details
        • Product supply
      • OS Open Names Getting Started Guide
        • Obtaining OS Open Names data
        • CSV file processing
        • Loading the data in a GIS
      • OS Open Names Technical Specification
        • Source of OS Open Names
        • Viewing resolution
        • Product structure
        • Feature type
          • NamedPlace
        • Code lists
          • LanguageValue
          • NamedPlaceTypeValue
          • LocalTypeValue
        • Structured data types
          • GeographicalName
          • Identifier
        • Local Type
        • Supply formats overview
        • Attribute naming format comparison
        • LocalType code list
      • OS Open Names Downloads
      • OS Open Names Known Data Issues
    • Points of Interest
      • Release Notes
        • March 2025
        • December 2024
        • September 2024
        • June 2024
      • Points of Interest Product Information
        • Using Points of Interest
        • Data measures and data sources
        • Classification scheme
        • Points of Interest Provenance
        • Glossary
        • Points of Interest symbology
      • Points of Interest Technical Specification
        • Using Points of Interest
        • Pipe delimited text (PDT) file format
          • Record structure
        • Code lists
          • Positional Accuracy
          • Match Indicator
        • Example records
        • Glossary
      • Points of Interest Classification Scheme
        • Accommodation, eating and drinking
        • Commercial services
        • Attractions
        • Sport and entertainment
        • Education and health
        • Public infrastructure
        • Manufacturing and production
        • Retail
        • Transport
      • Points of Interest Class Count
        • Accommodation, eating and drinking
        • Commercial services
        • Attractions
        • Sport and entertainment
        • Education and health
        • Public infrastructure
        • Manufacturing and production
        • Retail
        • Transport
      • Points of Interest Downloads
      • Points of Interest Known Data Issues
  • Contextual or derived mapping
    • Contextual or Derived Mapping Portfolio Information
    • Colour Raster Map Fundamentals
      • Colour Raster Map Overview
        • Metadata
        • Data compression
        • Data measures
        • Product supply
      • Colour Raster Map Technical Specification
        • Georeferencing
        • Image file directory (TIFF)
        • Abbreviations used on OS 1:25 000 and 1:50 000 scale mapping
        • Product glossary
    • 1:25 000 Scale Colour Raster
      • 1:25 000 Scale Colour Raster Overview
        • Product details
        • Features depicted in the product
        • Georeferencing
      • 1:25 000 Scale Colour Raster Technical Specification
      • 1:25 000 Scale Colour Raster Downloads
      • 1:25 000 Scale Colour Raster Known Data Issues
    • 1:50 000 Scale Colour Raster
      • 1:50 000 Scale Colour Raster Overview
        • Product details
        • Features depicted in the product
        • Georeferencing
      • 1:50 000 Scale Colour Raster Technical Specification
      • 1:50 000 Scale Colour Raster Downloads
      • 1:50 000 Scale Colour Raster Known Data Issues
    • 1:250 000 Scale Colour Raster
      • 1:250 000 Scale Colour Raster Overview
        • Product details
        • Georeferencing
        • Gazetteer
      • 1:250 000 Scale Colour Raster Technical Specification
      • 1:250 000 Scale Colour Raster Downloads
      • 1:250 000 Scale Colour Raster Known Data Issues
    • GB Overview Maps
      • GB Overview Maps Downloads
      • GB Overview Maps Known Data Issues
    • MiniScale
      • MiniScale Product Guide
        • Supply and formats
        • Georeferencing
        • Depiction of roads and towns
        • Data compression
        • Features, layers and styles
      • MiniScale Technical Specification
        • National Grid
        • MiniScale file management
      • MiniScale Downloads
      • Miniscale Known Data Issues
    • OS Open Zoomstack
      • OS Open Zoomstack Getting Started Guide
        • Zoomstack vector tiles
        • Zoomstack GeoPackage format
      • OS Open Zoomstack Technical Specification
        • List of Layers
        • Description of the cartographic styles
        • Sea Extent and Name Languages
        • Vector Tiles Schema
        • GeoPackage Schema
      • OS Open Zoomstack Known Data Issues
    • OS OpenMap – Local
      • Release Notes
        • April 2025
      • OS OpenMap – Local Overview
        • Product applications and uses
        • Product details
        • Product supply
      • OS OpenMap – Local Getting Started Guide
        • Loading raster data
        • Loading vector data
        • Loading and displaying GML Data
        • POSTGIS
        • Loading and displaying Shapefile supply
        • Viewing the data in QGIS
        • Using shapefiles in PostGIS
        • Using MapInfo Professional
      • OS OpenMap – Local Technical Specification
        • Data structure
        • Feature types
          • Building
          • ElectricityTransmissionLine
          • Glasshouse
          • RailwayStation
          • RailwayTrack
          • RailwayTunnel
          • Road
          • RoadTunnel
          • Roundabout
          • MotorwayJunction
          • CarChargingPoint
          • Foreshore
          • SurfaceWater_Area
          • SurfaceWater_Line
          • TidalBoundary
          • TidalWater
          • Woodland
          • FunctionalSite
          • ImportantBuilding
          • NamedPlace
        • Code lists
          • RailwayStationClassification
          • RailwayTrackClassification
          • DrawLevelValue
          • OverrideValue
          • RoadClassification
          • RoundaboutClassification
          • CarChargingType
          • RatedVoltage
          • ChargeMethod
          • TidalBoundaryClassification
          • BuildingTheme
          • BuildingClassification
          • SiteClassification
          • FontHeightClassification
          • NamedPlaceClassification
      • OS OpenMap – Local Downloads
      • OS OpenMap – Local Known Data Issues
    • OS VectorMap District
      • OS VectorMap District Overview
        • Generalisation
        • Feature types
        • Style definition
        • Product supply
      • OS VectorMap District Technical Specification
        • GML Overview
        • Raster Specification
        • Georeferencing
        • Feature types
          • Building
          • ElectricityTransmissionLine
          • Glasshouse
          • RailwayStation
          • RailwayTrack
          • RailwayTunnel
          • MotorwayJunction
          • Road
          • RoadTunnel
          • Roundabout
          • Foreshore
          • SurfaceWater_Area
          • SurfaceWater_Line
          • TidalBoundary
          • TidalWater
          • Ornament
          • Woodland
          • FunctionalSite
          • NamedPlace
          • SpotHeight
          • AdministrativeBoundary
        • Code lists
          • RailwayStationClassification
          • RailwayTrackClassification
          • RoadClassification
          • RoundaboutClassification
          • DrawLevelValue
          • OverrideValue
          • TidalBoundaryClassification
          • FunctionalSiteClassification
          • NamedPlaceClassification
          • FontHeightClassification
          • AdministrativeBoundaryClassification
        • Attributes
        • Feature Codes
        • Styling of Land and Sea
      • Vector Simple Guide
        • Downloading OS OpenData
        • Opening OS OpenData in QGIS
        • Styling vector data
        • Opening and saving maps in Composer
      • Raster Simple Guide
        • Downloading OS OpenData
        • Opening OS OpenData in QGIS
        • Opening and saving a map in composer
      • OS VectorMap District Downloads
      • OS VectorMap District Known Data Issues
    • OS VectorMap Local
      • Release Notes
        • January 2025
      • OS VectorMap Local Overview
        • Product details
        • Features represented in the product
        • Product style definition
        • Product supply
        • National Grid coverage for OS VectorMap Local
      • OS VectorMap Local Technical Specification
        • GeoPackage overview
        • GML overview
        • Raster data
        • Feature types
          • Area
          • Line
          • VectorMapPoint
          • RoadCLine
          • RailCLine
          • Text
        • Code lists
          • DrawLevelValue
          • AnchorPositionValue
          • TextFontValue
        • Structured data types
          • textRenderingType
        • Feature codes and descriptions
        • Vector tiles overview
        • Important Buildings classification
      • OS VectorMap Local Downloads
      • Supporting documents
        • OS VectorMap Local Cartographic Style Definitions
      • OS VectorMap Local Known Data Issues
  • Networks
    • Networks Portfolio Information
    • OS Detailed Path Network
      • OS Detailed Path Network Overview
        • Product details
        • Attribution
        • Product supply
        • Coordinate reference system
      • OS Detailed Path Network Getting Started Guide
        • Downloading the data
        • Loading GML data
      • OS Detailed Path Network Technical Specification
        • OS Detailed Path Network structure
        • Feature types
          • Route
          • RouteLink
          • RouteNode
        • Structured data types
          • VerticalGainType
        • Code lists
          • LevelCodeValue
          • PotentialHazardValue
          • RightOfWayValue
          • RouteDescriptiveGroupValue
          • RouteDescriptiveTermValue
          • RouteLinkDescriptiveTermValue
          • RouteNodeDescriptiveTermValue
          • SurfaceTypeValue
        • Data quality
        • GML overview
        • GeoPackage overview
          • Route
          • RouteLink
          • RouteNode
        • Vector Tiles overview
          • Route
          • RouteLink
        • GML examples
      • OS Detailed Path Network Downloads
      • OS Detailed Path Network Known Data Issues
    • OS MasterMap Highways Network Fundamentals
      • Release Notes
        • May 2025
        • April 2025
        • March 2025
        • February 2025
        • January 2025
        • December 2024
        • November 2024
        • October 2024
        • September 2024
        • August 2024
        • July 2024
        • June 2024
      • OS MasterMap Highways Network Product Family
      • OS MasterMap Highways Network Overview
        • Standards
        • Coordinate reference system
        • Feature types
          • Road Link (present in Roads & RAMI products)
          • Road Node (present in Roads & RAMI products)
          • Path Link (present in Paths product)
          • Path Node (present in Paths product)
          • Connecting Link (present in Paths product)
          • Connecting Node (Present in Paths product)
          • Road (present in Roads & RAMI products)
          • Path (present in Paths product)
          • Street (present in all OS MasterMap Highways Network products)
          • Road Junction (present in Roads & RAMI products)
          • Ferry Link (present in all OS MasterMap Highways Network products)
          • Ferry Node (present in all OS MasterMap Highways Network products)
          • Ferry Terminal (present in all OS MasterMap Highways Network products)
          • Access Restrictions (present in RAMI product)
          • Turn Restrictions (present in RAMI product)
          • Restrictions For Vehicles (present in RAMI product)
          • Hazards (present in RAMI product)
          • Structures (present in RAMI product)
          • Maintenance (present in RAMI & Paths products)
          • Reinstatement (present in RAMI & Paths products)
          • Highways Dedication (present in RAMI & Paths products)
          • Special Designations (present in RAMI & Paths products)
        • Product supply
        • Product packaging
        • File naming
        • Feature validation data set
        • Volume feature count
        • OS Open Roads Lookup Table
      • OS MasterMap Highways Network Getting Started Guide
        • What do I need to use this data?
        • Product supply
        • Coverage
        • Product packaging
        • File naming
        • Unzipping GML, GeoPackage, and vector tiles files
        • Loading OS MasterMap Highways Network products into a GIS
        • Relationships between Highways tables
      • OS MasterMap Highways Network Playbook
        • Connecting to Address Data
        • Identifying Change in the Network
        • Highlighting Roads Under Construction
        • Creating a Map of Winter Gritting Routes
        • Adding Road Names and Numbers to a Map
        • Merging Tables and Dropping Geometry
        • Creating a Routable Network
      • OS MasterMap Highways Network Downloads
      • OS MasterMap Highways Network Known Data Issues
    • OS MasterMap Highways Network – Roads
      • OS MasterMap Highways Network Overview
      • OS MasterMap Highways Network – Roads Technical Specification
        • Specification changes
        • Structure
        • How the product fits together
        • Change-Only Update (COU) supply
        • Feature types
          • RoadLink
          • RoadNode
          • Road
          • Street
          • RoadJunction
          • FerryLink
          • FerryNode
          • FerryTerminal
        • Structured data types
          • identifier
          • OperationalStateType
          • DesignatedNameType
          • ResponsibleAuthority
          • CycleFacilityType
          • ElevationGainType
          • RoadWidthType
        • Code lists and Enumerations
          • ChangeValue
          • RoadClassificationValue
          • RoadFunctionValue
          • MatchStatusValue
          • OperationalStateValue
          • ProvenanceSourceValue
          • RoadStructureValue
          • LinkDirectionValue
          • FormOfWayValue
          • CycleFacilityValue
          • RoadWidthConfidenceLevelValue
          • FormOfRoadNodeValue
          • RoadNodeClassificationValue
          • AccessPointValue
          • StreetTypeValue
          • JunctionTypeValue
          • ConnectionTypeValue
          • FormOfWaterwayNodeValue
        • GML overview
        • GeoPackage overview
          • ferry_link
          • ferry_node
          • ferry_terminal
          • road
          • road_junction
          • road_link
          • road_node
          • street
        • Vector tiles overview
          • ferry_link
          • ferry_node
          • ferry_node
          • road_link
          • road_node
          • street
        • GML examples
      • OS MasterMap Highways Network Getting Started Guide
      • OS MasterMap Highways Network Known Data Issues
    • OS MasterMap Highways Network – Routing and Asset Management Information
      • OS MasterMap Highways Network Overview
      • OS MasterMap Highways Network – Routing and Asset Management Information Technical Specification
        • Specification changes
        • How the product fits together
        • Routing and Asset Management feature information
          • Data types
            • NetworkReference
            • NodeReference
            • LinkReference
            • PointReference
            • Multiple Link Reference
            • Point Reference
        • Common attribution
        • Rights and Restrictions
          • Feature types
            • AccessRestriction
            • HighwayDedication
            • TurnRestriction
            • RestrictionForVehicles
        • Advisory information
          • Feature types
            • Hazard
            • Structure
        • Asset management
          • Feature types
            • Maintenance
            • Reinstatement
            • Special Designation
        • Change-Only Update (COU) supply
        • Code lists and enumerations
          • ChangeValue
          • UseTypeValue
          • VehicleTypeValue
          • LoadTypeValue
          • NamedDateValue
          • NamedDayValue
          • NamedPeriodValue
          • NamedTimeValue
          • AccessRestrictionValue
          • DedicationValue
          • TurnRestrictionValue
          • RestrictionTypeValue
          • HazardTypeValue
          • StructureTypeValue
          • ReinstatementTypeValue
          • SpecialDesignationTypeValue
          • LinkDirectionValue
          • MaintenanceValue
        • Data types
          • TemporalPropertyType
          • DateRangeType
          • DayPropertyType
          • TimePropertyType
          • TimeRangeType
          • TrafficRegulationOrderType
          • VehicleQualifier
          • ResponsibleAuthority
          • Identifier
        • GML overview
        • GeoPackage overview
          • Access Restriction
          • Highway Dedication
          • Turn Restriction
          • Restriction for Vehicles
          • Hazard Point
          • Hazard
          • Structure Point
          • Structure
          • Maintenance
          • Maintenance Point
          • Maintenance Line
          • Maintenance Area
          • Reinstatement
        • GML examples
      • OS MasterMap Highways Network Getting Started Guide
      • OS MasterMap Highways Network Known Data Issues
    • OS MasterMap Highways Network – Paths
      • OS MasterMap Highways Network Overview
      • OS MasterMap Highways Network – Paths Technical Specification
        • Specification changes
        • Structure
        • How does the product fit together?
        • Change-Only Update (COU) Supply
        • Feature types
          • PathLink
          • PathNode
          • ConnectingLink
          • ConnectingNode
          • Path
          • Street
          • FerryLink
          • FerryNode
          • FerryTerminal
          • Maintenance
          • Reinstatement
          • SpecialDesignation
          • HighwayDedication
        • Structured data types
          • Identifier
          • CycleFacilityType
          • ElevationGainType
          • OperationalStateType
          • DesignatedNameType
          • ResponsibleAuthority
          • TemporalPropertyType
          • DateRangeType
          • DayPropertyType
          • TimePropertyType
          • TimeRangeType
        • Data types
          • NetworkReferenceLocation
          • Temporal Properties
        • Code lists and Enumerations
          • ChangeValue
          • FormOfWayValue
          • SurfaceTypeValue
          • MatchStatusValue
          • ProvenanceSourceValue
          • CycleFacilityValue
          • FormOfRoadNodeValue
          • RoadNodeClassificationValue
          • OperationalStateValue
          • StreetTypeValue
          • ConnectionTypeValue
          • FormOfWaterwayNodeValue
          • DedicationValue
          • ReinstatementTypeValue
          • SpecialDesignationTypeValue
          • MaintenanceValue
        • GML Overview
        • GeoPackage overview
          • connecting_link
          • connecting_node
          • ferry_link
          • ferry_node
          • ferry_terminal
          • highway_dedication
          • maintenance
          • path
          • path_link
          • path_node
          • reinstatement
          • special_designation
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On this page
  • Creation of polygon features due to real-world change
  • Deletion of polygon features due to real-world change
  • Modification of polygon features due to real-world change
  • Changes to geometry of polygon features
  • Examples
  • Splitting of polygon features
  • Examples
  • Joining of polygon features
  • Examples
  • Change of polygon feature classification
  • Examples
  • Modification of polygon features due to error correction
  • Examples

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  1. Topography
  2. OS MasterMap Topography Layer
  3. OS MasterMap Topography Layer Technical Specification
  4. Feature lifecycles and tracking change

Polygon feature lifecycle rules

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Last updated 8 months ago

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The flowchart below shows the process followed whenever a real-world object represented as an OS MasterMap Topography Layer polygon feature appears, changes, or is removed from the physical environment (i.e. referred to as Inserts, Updates and Deletes). The rules are described in more detail in the following sub-sections, particularly the guidelines used to answer the question in the centre of the flowchart (i.e. 'Is it still the same real-world object?').

Creation of polygon features due to real-world change

When a new real-world object with an area (for example, a building or pond) comes into being, a new polygon feature is created in the data, with a new TOID and version number. Users with local holdings of OS MasterMap Topography Layer data will be informed of new features in their holding via Change-Only Update (COU).

Deletion of polygon features due to real-world change

When an object represented as a polygon feature no longer exists in the real world, the polygon feature is deleted from the database. A record is kept in the database to indicate that a feature with this TOID used to exist and when it was deleted. Users with local holdings of OS MasterMap data are informed of the deletion in their next COU.

Modification of polygon features due to real-world change

When an object represented as a polygon feature changes but is considered to be still the same real-world object, the corresponding modified feature is retained in the database. The version number is incremented and the date on which the new version became current is stored.

If, however, the real-world object has undergone change to such a degree that it is not considered to be the same object as before, the polygon feature representing it is deleted and one or more new features created.

Changes to geometry of polygon features

When a real-world polygon object expands or contracts, due to alteration to its bounding lines, it is considered to be the same real-world object, and as such retains its TOID. For example, the polygon feature representing the back garden of a property is retained, even if it is greatly reduced in size due to extension work done to the house. This is because its identity and association to a property remains unchanged despite extensive changes to its geometry.

If it is not clear whether the real-world object after modification is the same object or a new one, the following considerations are used as a guideline:

  • Is there topographic information to suggest the function of the resultant real-world object is the same as that of the original?

  • Is the resultant real-world object more than half the size and less than twice the size of the original?

  • Does the majority of the extent of the resultant real-world object lie within the bounds of the original?

  • Is the resultant real-world object the obvious logical successor to the original?

If the continuation of the feature cannot be justified on one or more of these grounds, the feature is deleted and replaced with a new feature.

Examples

  • A private house is extended. The building and garden features are retained.

  • A field changes shape and reduces in size due to the realignment of one of its boundary fences alongside a road. The field feature and the adjacent road features are retained.

Splitting of polygon features

When a real-world polygon object is split into two or more separate real-world objects, one of the features may be clearly recognisable as the original real-world object. If this is the case, then the feature is retained.

If it is not clear whether one of the resultant features represents the same real-world object as the original feature, then the following considerations are used as a guideline:

  • Is the function of one of the resultant real-world objects the same as the original?

  • Is one of the resultant real-world objects the obvious logical successor to the original?

  • Does one of the resultant real-world objects occupy more than half the area of the original?

If the continuation of the feature cannot be justified on one or more of these grounds, the original feature is deleted and replaced with new features.

Examples

  • A new housing development is completed within an agricultural field. Part of the field remains and continues to be used for agriculture. The feature representing the remainder of the field is recognisable as the original with the same function, therefore it is retained. New polygon features are created to represent the new housing development.

  • An agricultural field is subdivided into three approximately equal parts that continue to be in similar usage. Using the guidelines above, none of the fields can be considered the obvious successor to the original field: all have an area less than half of the original; therefore, the original feature is deleted and three new features are created.

  • A house is divided equally in two by an externally surveyable division. The original feature is deleted and new features are created. This is because neither of the resultant houses is the obvious successor to the original.

  • A large agricultural building is split into two by the addition of an externally surveyable division enclosing approximately 25% of the original area. The original feature is retained to represent the larger part, and a new feature is created to represent the smaller part.

  • Most of the large garden of a residential property is sold off for development. The garden feature is retained to represent the much-reduced garden.

Joining of polygon features

When two or more real-world polygon objects are merged by the removal of physical boundaries, it may be that one of the original real-world objects is clearly recognisable as subsuming the other. If that is the case, the feature representing the dominant real-world object is retained and the other feature is deleted.

If one of the original real-world objects is not clearly dominant, the following considerations are used as a guideline to determine whether a feature is retained:

  • Is the function of the resultant real-world object the same as one of the originals?

  • Can one of the original real-world objects be considered the obvious predecessor to the resultant real-world object?

  • Is the area of the resultant real-world object less than twice that of one of the original real-world objects?

If the continuation of the feature cannot be justified on one or more of these grounds, all the original features are deleted and replaced with new features.

Examples

  • Two fields, one of which is larger than the other, are merged into one, such that the resultant real- world object is recognisable as the larger field subsuming the smaller field. The feature representing the larger field is retained. The smaller field feature is deleted.

  • Three fields, which are broadly similar in size, are merged into one, such that none of the original fields are recognisable as the obvious predecessor of the resultant field. The original features are deleted, and a new feature is created to represent the field.

  • A pond within a field is filled in. The feature representing the pond is deleted and the field feature is retained.

  • Two semi-detached cottages of equal size are combined into one dwelling, with no alteration to the external geometry of the building. Both of the original features are deleted, and a new feature is created.

  • A large greenhouse lies within a parcel of land only marginally larger than itself. The greenhouse is demolished. The feature representing the greenhouse is deleted, and the feature representing the land parcel is deleted as it has increased significantly and can no longer be considered as the same object.

Change of polygon feature classification

When a real-world object represented by a polygon feature changes such that the nature of the feature changes, the feature is retained, unless changes to its geometry indicate deletion of the feature under the guidelines above.

Examples

  • An area of agricultural land is wholly planted with trees; there are no changes to its bounding features. The descriptive group of the feature changes but its geometry is unchanged. The feature is retained.

  • An area of woodland is felled, and the area now consists of rough grass and scrub. The feature is retained.

  • A barn is converted into a private dwelling. There is no change to the nature of the building (it is still a building) and the feature is retained.

Modification of polygon features due to error correction

When a polygon feature is changed solely to correct errors either in geometry or other attributes, the feature is retained. If the feature has been moved to correct an error and simultaneously modified for real-world change; for example, when natural movement of a physical feature occurs, such as a riverbank or foreshore, then the feature modification rules above are followed.

Examples

  • A line feature representing an old fence is found to have an error in its position and is corrected. The line feature and the polygon features bounded by it are retained. The version numbers of the features are incremented.

  • The feature representing an area of road has been assigned an incorrect descriptive group. The feature is reclassified and retained. The feature version number is incremented.

  • An area of non-coniferous trees has been incorrectly assigned the descriptive term 'coniferous trees' by photogrammetric revision techniques. The feature is reclassified and retained. The feature version number is incremented.

  • A building foundation captured as a feature with a descriptive group of ‘unclassified’ is completed, and the feature is reclassified to a descriptive group of ‘building’. The feature is retained. The feature version number is incremented.

  • A feature is no longer included within Ordnance Survey’s capture specification. The feature is not retained.

Polygon feature creation process in OS MasterMap Topography Layer.
Flowchart outlining the polygon feature creation process in OS MasterMap Topography Layer.