> For the complete documentation index, see [llms.txt](https://docs.os.uk/osngd/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/osngd/using-os-ngd-data/os-ngd-transport/transport-networks-in-the-os-ngd/national-street-gazetteers-geoplace-and-improvement-service.md).
# National Street Gazetteers, GeoPlace and Improvement Service
This page describes the authoritative data sources for the OS NGD Transport Theme.
The [OS Transport Network](/osngd/data-structure/transport/transport-network.md) and [OS Routing and Asset Management Information (RAMI)](/osngd/data-structure/transport/rami.md) Collections integrate Ordnance Survey's detailed road and path information with the authoritative sources of the National Street Gazetteer, Trunk Road Street Gazetteer, and National Street Gazetteer for Scotland. These sources contain the definitive information provided by the Local and National Roads and Highways Authorities.
Each highway authority in England and Wales is required to create and maintain its own Local Street Gazetteer (LSG) and Associated Street Data; these are then compiled into the National Street Gazetteer by GeoPlace. GeoPlace is a limited liability partnership jointly owned by the Local Government Association and Ordnance Survey.
In Scotland, the National Street Gazetteer for Scotland is compiled by Improvement Service.
In addition to this, National Highways, Transport Scotland and Traffic Wales provide information on trunk roads in England, Scotland and Wales.
Data sources for the OS NGD Transport Theme.
Streets as defined by Local Highway Authorities and National Transport Agencies are matched with OS Road Links and Path Links, combining the authoritative gazetteer information on street naming, numbering and maintenance with detailed OS-surveyed geometry and attribution.
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