> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/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/os-downloads/~/changes/AJZwzCsyrD9hiTbOxIbO/identifiers/os-open-linked-identifiers/os-open-linked-identifiers-technical-specification/orroadlink_guid_roadlink_toid_12.md). # ORRoadLink\_GUID\_RoadLink\_TOID\_12 This document aims to provide all the information to evaluate if the method of associating the respective identifiers is suitable for your needs. These identifier relationships have been extracted from existing premium products and are presented in a standalone table for easy and open access to the information. It describes which product the information was extracted from, what information was extracted and how the source product derived the original association between the identifiers.

OS Open Roads and OS MasterMap Highways products showing GUID and TOID identifier types for RoadLink and RoadNode features

## Relationship Extraction This relationship is between the unique identifier (GUID) of the RoadLink features in *OS Open Roads* and the Topographic Identifier (TOID) of RoadLink features in *OS MasterMap Highways Network* which represent the same feature. The relationship is extracted from the OS Open Roads Lookup table which is supplied with the *OS Master Map Highways Network – Roads*. This table provides the TOID of the RoadLink feature in the *OS MasterMap Highways Network* and the GUID of the ORRoadLink feature in *OS Open Roads* which represent the same feature in *OS Open Roads*. ## Correlation Method This relationship is determined using the OS Open Roads Lookup table which is supplied with the *OS Master Map Highways Network – Roads*. This table provides the TOID of the RoadLink feature in the *OS MasterMap Highways Network* and the GUID of the ORRoadLink feature in *OS Open Roads* which represent the same feature in *OS Open Roads*. This relationship is created by Ordnance Survey using a spatial match between systematically sampled points along the two line feature datasets. The two source products for these identifiers are on different refresh cycles. *OS MasterMap Highways Network - Roads* is updated monthly, whereas *OS Open Roads* is updated every six months. As this product utilises published source products, the current data available for each identifier might have changed and therefore the relationship may not still be valid. A Confidence Value is assigned to indicate the reliability of the version information provided in this product in relation to the version of the features used to form the correlation in the original product. The Confidence Value is given for each relationship, which is defined as follows:

Confidence Value	Definition
Version information is correct	The version information provided is the same as the version of the feature used to create the correlation.
Version information has potentially changed	The version information could be different from the version of the feature that was used to create the correlation.
Version information has changed	The version information provided is different from the version of the feature used to create the correlation.

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