# OS VectorMap Local Technical Specification

OS VectorMap Local is a mapping dataset designed for providing contextual mapping output on paper, PCs, hand-held devices or the Internet. The vector format of the product consists of layers to enable you to customise and style the output to suit your needs.

The product is generated automatically from the OS Large-Scale Topographic Database with no manual cartographic input. This database is used to update other OS products, including [OS MasterMap Topography Layer](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/broken-reference).

This Technical Specification contains detailed technical information about the data in both raster and vector formats. For basic information required to understand and use OS VectorMap Local, please refer to the [product overview page](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-overview).

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FPmqZTksx32GUpdKPc327%2F1.png?alt=media" alt="OS VectorMap Local Full Colour Raster map example."><figcaption><p><em>OS VectorMap Local Full Colour Raster map example.</em></p></figcaption></figure>

## Vector data <a href="#id-4.-vector-data" id="id-4.-vector-data"></a>

### Available formats <a href="#id-4.1-available-formats" id="id-4.1-available-formats"></a>

OS VectorMap Local is available in three vector formats:

* Geography Markup Language (GML) 3.2.1
* GeoPackage
* Vector tiles (MBTiles)

These file formats contain a set of features and identifiers which conform to the data structures outlined in the following sub-sections.

## Identifiers <a href="#id-4.2-identifiers" id="id-4.2-identifiers"></a>

In OS VectorMap Local vector data for GML, vector tiles and GeoPackage formats, each feature is given a unique identifier: a featureID. The featureIDs are maintained between iterations. For GML only, this allows feature-level change-only updates (COUs) to be delivered. The COUs will consist of a selection of inserts and deletes related to real-world and generalisation generated change (see the [GML overview](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/gml-overview) page of this document for more information). Vector tiles and GeoPackage formats do not have a COU option.

## UML class diagrams and table conventions <a href="#id-4.3-uml-class-diagrams-and-table-convent" id="id-4.3-uml-class-diagrams-and-table-convent"></a>

The data structure is described below by means of unified modelling language (UML) class diagrams and accompanying tables containing text. The UML diagrams conform to the approach specified in the ISO 19103 Conceptual Schema.

Colour conventions have been used in the diagrams and tables to distinguish the properties that have been added in this specification. In the UML class diagrams, feature types in the Ordnance Survey product specification are coloured orange. The tables which follow in this Technical Specification use orange for a feature type, blue for a code list and purple for a data type.

### Stereotypes <a href="#id-4.4-stereotypes" id="id-4.4-stereotypes"></a>

The following stereotypes are used on UML elements:

#### *The stereotypes used on UML elements.*

| Stereotype  | UML element | Description                                                                |
| ----------- | ----------- | -------------------------------------------------------------------------- |
| FeatureType | Class       | A spatial object type \[ISO 19136].                                        |
| Codelist    | Class       | A controlled set of values for a free text data type that may be extended. |
| DataType    | Class       | Structured data type.                                                      |

## Index

* [GeoPackage overview](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/geopackage-overview)
* [GML Overview](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/gml-overview)
* [Raster data](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/raster-data)
* [Feature types](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/feature-types)
* [Code lists](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/code-lists)
* [Structured data types](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/structured-data-types)
* [Feature codes and descriptions](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/feature-codes-and-descriptions)
* [Vector tiles overview](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/vector-tiles-overview)
* [Important Buildings classification](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-local/os-vectormap-local-technical-specification/important-buildings-classification)


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