GML

Boundary-Line layers are supplied in Geography Markup Language (GML) v.3.2.1.

GML is based on XML (eXtensible Mark-up Language) and an understanding of the XML schema will be helpful in understanding the GML format.

See the following Geography Markup Language v3.2.1 OpenGIS® Geography Markup Language (GML) Encoding Standard (PDF download) document by the Open Geospatial Consortium (OGC) for full details about GML.

Boundary-Line GML files are only created for the following layers:

• County

• District_borough_unitary

• Parish

Schema overview and location

XML schemas are used to define and validate the format and content of the GML. The GML v.3.2.1 specification provides a set of schemas that define the GML feature constructs and geometric types. These are designed to be used as a basis for building application-specific schemas, which define the data content.

The AdministrativeUnits.xsd application schema which is referenced by the data, is available on the INSPIRE website. It imports the GML 3.2 schemas which rely on XML as defined by W3C.

Style sheets have been created and provided for Boundary-Line GML. You can find these in the Ordnance Survey GitHub repository at https://github.com/OrdnanceSurvey/Boundary-Line-stylesheets.