GML overview

Simple Features – Level 1

The Geography Markup Language (GML) data conforms to GML Simple Features Profile Level 1. In this release of the product, the only thing that does not conform to level 0 is the inspireId.

The geometries that we use are OGC ‘simple’: points, and line strings with linear interpolation.

Schemas

XML schemas are used to define and validate the format and content of the GML. The GML 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 Ordnance Survey application schema waterNetwork.xsd, which is referenced by the data, is available on our website. It imports the INSPIRE Hydrography networks application schema, which in turn imports the GML 3.2.1 schemas. These in turn import schemas produced by the W3C. The data contains elements and attributes from a range of namespaces:

The XML namespaces used by the application schema and their definitions:

Namespace Identifier	Short Form Prefix	Application Schema
http://namespaces.os.uk/mastermap/waterNetwork/1.0	water	OS MasterMap Water Network Layer
urn:x-inspire:specification:gmlas:HydroNetwork:3.0	hy-n	INSPIRE Hydrography networks
urn:x-inspire:specification:gmlas:Network:3.2	net	INSPIRE generic network
urn:x-inspire:specification:gmlas:BaseTypes:3.2	base	INSPIRE base types
http://www.opengis.net/gml/3.2	gml	OGC GML 3.2.1
http://www.w3.org/1999/xlink	xlink	W3C XML Linking
http://www.w3.org/2001/XMLSchema-instance	xsi	W3C XML Schema instance