> 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/cycle-lanes/how-cycle-lane-data-are-created.md). # How cycle lane data are created ## How does OS source cycle lane data? Cycle lane data are sourced from OS aerial imagery, where cycle lanes exist alongside publicly accessible Road Links and Path Links. Where features are not visible from aerial imagery (for example, where there is no visible evidence of a cycle lane or where it is obscured by tree cover), these will not be included; please see [known limitations](/osngd/using-os-ngd-data/os-ngd-transport/cycle-lanes/known-limitations.md) for more information on completeness limitations for cycle lane data. Some additional capture using targeted ground surveying based on intelligence sources has also been used to capture cycle lanes. ## How are Cycle Lane features linked to Road Link and Path Link features? An algorithm is used to link the Cycle Lane feature to a Road Link or Path Link. This algorithm uses a buffer from the Cycle Lane feature and analyses the angle of Road Links and Path Links within that buffer to determine which Road Link or Path Link the Cycle Lane feature is alongside. This is then referenced in the Link ID attribute. In order to provide a one-to-one relationship between Cycle Lane features and Road Links or Path Links, Cycle Lane features are split into links in line with Road and Path Link geometry. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.os.uk/osngd/using-os-ngd-data/os-ngd-transport/cycle-lanes/how-cycle-lane-data-are-created.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.