OS NGD Transport RAMI

A Lightning Talk

What layers are in OS NGD Transport RAMI​

There are 14 geometry layers and 8 cross-reference layers in the OS NGD Transport RAMI collection. The main feature with this data is that where Highways only referenced features, in OS NGD they have been given a geometry – restriction, routing hazard, special designation, etc.

Geometry Layers

• Maintenance Area​

• Maintenance Line​

• Maintenance Point​

• Reinstatement Area​

• Reinstatement Line​

• Reinstatement Point​

• Special Designation Area

• Special Designation Line​

• Special Designation Point​

• Restriction​

• Routing Hazard​

• Routing Structure​

• Highway Dedication​

• Average and Indicative speeds​

Cross Reference Layers

• Highway Dedication – ​Street/Road Link/Path Link​

• Restriction – Road Link​

• Restriction – Date/Time Qualifier​

• Routing Hazard - Road Link​

• Routing Structure – Road Link​

• Special Designation Area – Date/Time Qualifier​

• Special Designation Line – Date/Time Qualifier​

• Special Designation Point – Date/Time Qualifier​

OS NGD Transport RAMI

OS NGD Transport RAMI Geometry Feature Types

There are four groups in geometry tables of OS NGD Transport RAMI:

Maintenance

Maintenance

These features give information about who maintains the Street, is it at the public expense or not, to another authority or out of scope. There is information on lines replicating nearly all of the road network geometry, however whether data is recorded as a Point or an Area varies between different authorities. So Devon (left) uses Areas, Dorset (right) uses Points

Reinstatement

Reinstatement

This is information about the surface of the Street if it needs to be reinstated, such as carriageway type, coloured surface and friction coating.

Special Designation

Special Designation

These are sections of Street that have a specific remit, such as Special Engineering Difficulty, Environmentally Sensitive Areas and Structures.

Routing

Routing

This includes information about turn restrictions, vehicle restrictions, access restrictions, hazards and structures and link back to Road Nodes or Road Links. Whereas highway dedication (all vehicles, pedestrian, motorway and so on) links to Streets.

OS NGD Transport RAMI Average and Indicative Speeds

A set of RAMI data that is new to the PSGA has been added into OS NGD in March 2023. It includes Average and Indicative Speeds, with information about average speeds at different times of the day:

• 0400 – 0700

• 0700 – 0900

• 0900 – 1200

• 1200 – 1400

• 1400 – 1600

• 1600 – 1900

• 1900 – 2200

• 2200 – 0400

As well as information about different times of the week:

Monday – Friday

Saturday – Sunday

Like other RAMI data it has a geometry and also cross references back to the USRNs that the speed information applies to.

OS NGD Transport RAMI styled by speeds data

Data Cross Referencing

Although all of the features in OS NGD Transport RAMI have now got a geometry a series of cross reference table exist to link the geometry of the RAMI data to the Geometry of the underlying Road Links and Streets, as well as to link to Date and time Qualifiers that are not spatial.

data model of data cross referencing

Data cross referencing visualised on a map

What formats does the OS NGD Transport RAMI data come in?

The OS NGD Transport RAMI data comes in two formats, CSV and GeoPackage (GPKG)

• The GeoPackage format comes ready to load into the GIS package of the users choice with different gpkg files for each layer.

• The CSV format is more suited for loading into a database. It has all of the same layers in csv format and all the same attribution as the GeoPackage, however instead of storing the geometry in a GIS ready format, it is stored as a MULTIPOINT, MULTILINESTRING, MULTIPOLYGON attribute with all of the vertices stored as co-ordinate pairs in the text file.

New Data Structure

The data in OS NGD Transport RAMI is very similar to that of OS MasterMap Highways Network. However, there are two major differences:

• Features comprising several links or a Street that in OS MasterMap Highways Network are only referenced are given an explicit geometry in OS NGD data. These include the Restrictions, Hazards, Structures, Highway Dedication, Maintenance, Reinstatement and Special Designation Time Qualifiers

• In OS MasterMap Highways Network the references between restrictions and the Road Links were arrays. Due to the new OS NGD data formats of GPKG and CSV there is no longer an array data type and these are held as a row per reference

Data structure with rows for each link making up a restriction

---

Links that may be useful:

OS NGD Documentation Platform | osngd

OS Data HubOrdnanceSurvey

OS Select+Build | OS productsOrdnance Survey

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