OS NGD Transport Features

A Lightning Talk

What are the layers in OS NGD Transport Features?

There are five layers in OS NGD Transport Features, all of which share geometry with OSMM Topography Layer

Road Track Path

Road, Track Path

Polygon features that include Roads, Paths, Central Reservations, Pavements, Traffic Calming and Curtilage (taken from OS MasterMap Topography Layer Roads Tracks and Paths theme)

Road Line

Cartographic Rail Detail

Rail

Street Light

Road Track Path feature type

There are now 4 different attributes in this data that allow the user to classify the polygons in the layer​

• Description: Similar to the description field in OS MasterMap Topography Layer but with expanded range of values​

• Land Cover Tier A: Gives a high-level land cover attribute, e.g. Trees​

• Land Cover Tier B: Gives a more detailed level of land cover information,​ e.g. Non-Coniferous Trees​

• Land Use Tier A: Gives a value for the use of the land, e.g. non-​coniferous trees that are on land used for ​Transport: Road, Track or Path​

The same principles also apply to Rail Feature Type.

More information on Land Cover enhancements can be found in the Land Cover Enhancements Lightning Talk

Transport Feature Type styled by Description

Road Line feature type​

​Currently contains traffic calming information in a linear form, representing two types of features. ​ This data should be used in conjunction with the Traffic Calming data from the road Track Path Feature Type​

Street Light feature type

The location of streetlights are represented by a point geometry.

Each street light point has been matched to the nearest roadlink or pathlink. The street light feature includes the following attribution about the match:

• The id of the matched link

• The feature type that it has been linked to

• The confidence of this match

Street light locations have been captured and extracted from aerial imagery.

Street Light features with attribution

Associated Structure​

The Transport Features include information about structures that the roads and rail are associated to such as a Bridge, Footbridge, Viaduct, Swing Bridge, Underpass and so on.​

• Physical Level​: There is also information on what Level the road or rail feature is on, such as Level 1 for a bridge over another road where the lower road would be at Surface Level​

• Data in other themes​: However, some features that comprise the Transport Infrastructure are stored in other themes. In the case of the Viaduct on the image this is in the Land theme for the polygon ‘on the ground’ and in the Compound Structure feature type.

Associated structure examples

What formats does the ​ OS NGD data come in?​

The OS NGD Transport Features data comes in two formats, Geopackage and CSV​

• Geopackage comes ready to load into a GIS package, with different .gpkg files for each layer.​

• CSV is more suited for loading into a database. It has the same layers and attribution as Geopackage but the geometry is stored as a POLYGON or LINESTRING attribute with vertices stored as co-ordinate pairs in the text.​

What is the attribution?​

• All OS NGD data has an OSID​

• The features have a TOID, version, version date and changetype

• Polygons feature Land Cover and Land Use as well as the evidence dates and update dates​

• Rail layers have Operational Status allowing users to identify ‘Active’ or ‘Inactive’ railway​

Transport Feature attribution

Source of the new attribution

Ordnance Survey surveyors and remote sensing teams have been capturing and maintaining information on land cover, land use and a more detailed level of description for over 10 years. ​

• In the case of Land Use, several classifications of Land Use have been captured but had not made it into the existing products​

• This data has been transformed to match attribution for existing products, such as OS MasterMap Topography Layer ​

However, in the OS NGD data it is being published at the original, more granular level

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Links that may be useful:

OS NGD Documentation | OS National Geographic Databaseosngd.gitbook.io

OS Data HubOrdnanceSurvey

https://www.ordnancesurvey.co.uk/business-government/products/os-select-buildwww.ordnancesurvey.co.uk

This content has been developed from what was originally a Lightning Talk PowerPoint slide set. These slides are available to PSGA members to view and download from the PSGA members area of the OS website