OS NGD Transport Features
A Lightning Talk
What are the layers in OS NGD Transport Features?
There are four layers in OS NGD Transport Features, all of which share geometry with OSMM Topography Layer
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 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
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
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.
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
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
Links that may be useful:
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
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