> 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/products/maps-and-imagery-portfolio/os-openmap-local/os-openmap-local-technical-specification.md). # OS OpenMap – Local Technical Specification This technical specification provides detailed technical information about OS OpenMap – Local. It is targeted at technical users and software developers. OS OpenMap – Local (OML) is the most detailed ‘street level’ open mapping product available and is designed to provide contextual mapping for your applications or web pages. It offers customers and OS Partners a clear contextual view of the world, whilst also enabling the undertaking of analytical activities. OS OML data is available as either pre-styled static images (raster) or interactive vectorised features in a selection of pre-defined or customisable styles. The vectorised format of the product consists of multiple layers of feature information which can be individually interrogated, displayed and styled to suit your needs. [Stylesheets](https://github.com/OrdnanceSurvey/OS-OpenMap-Local-stylesheets) are available for this product in GitHub. The rasterised layers provide pre-defined static contextual mapping that is designed to allow customers to overlay their own data clearly. More information on styling can be found in the [Getting Started Guide](/os-downloads/products/maps-and-imagery-portfolio/os-openmap-local/os-openmap-local-getting-started-guide.md). OS OML contains functional sites, greenspace, important buildings and Department for Transport (DfT) numbers in order to facilitate alignment with other OS products. When using OS OML for contextualised mapping, the nominal viewing scale is 1:10 000, with a recommended viewing scale range of 1:3 000 to 1:20 000. ## Index The OS OML technical specification is broken down into the following topics: * [Data structure](/os-downloads/products/maps-and-imagery-portfolio/os-openmap-local/os-openmap-local-technical-specification/data-structure.md) * [Feature types](/os-downloads/products/maps-and-imagery-portfolio/os-openmap-local/os-openmap-local-technical-specification/feature-types.md) * [Code lists](/os-downloads/products/addresses-and-names-portfolio/os-open-names/os-open-names-technical-specification/code-lists.md) --- # 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 by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-openmap-local/os-openmap-local-technical-specification.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. 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.