UK OS MasterMap Topography Layer (GML) Writer Parameters

OS MasterMap GML Version

Select from the locally installed schema, identified by the http://namespaces.ordnancesurvey.co.uk/mastermap/sites/v1.0 namespace, or by specifying an external XML schema file, via the Application Schema parameter.

A GML instance document specifies the namespace and the location of its application schema through its root element xsi:schemaLocation attribute. This field allows the GML (or GML-based) reader to use a different GML schema document from the one specified in the xsi:schemaLocation attribute.

The XML Schema specification states that the xsi:schemaLocation attribute value consists of a set of pairs: The first member of each pair is the namespace for which the second member is the hint describing where to find an appropriate schema document. The presence of this hint does not require the processor to obtain or use the cited schema document, however, the processor is free to use other schemas obtained by other suitable means.

Note  This only takes effect if the target namespace of the dataset is not in the Safe fixed schema namespace http://www.safe.com/xml/schemas/FMEFeatures. The GML2 writer in Fixed Schema Mode writes out documents that belong to that namespace.

SRS Parameters

This parameter can overwrite the CRS value that is written in the GML instance’s srsName attributes.

By default, the FME coordinate system name in a feature is transferred directly onto the srsName attribute. Using this parameter allows you to provide your own URN CRS string for the srsName attributes.

This parameter specifies the axis order for a coordinate tuple in a GML <pos> or <posList> element.

The valid values are

  • 1,2
  • 2,1
  • 1,2,3
  • 2,1,3

There is no default value.

Pretty Printing

Setting this parameter to Yes ensures the output is neatly formatted. This promotes easier reading on screen and in print output.

  • Indent Size – Select a value from 0 to 9.
  • Replace Tabs with Spaces  – By default, the Tab character is used to for indentations. Select Yes to substitute the Tab character with a Space.
  • Text Indent  – By default, the text in a tag is left untouched. Select Yes to include pretty printing in the text.
Note  Enabling this option produces a considerably larger output file due to added whitespace.

Feature Collection

The root collection element is influenced by this parameter.

  • FeatureCollection – In GML 3.1.1 mode, the default collection element is <gml:FeatureCollection>; the Feature Collection NS URI parameter may be used in conjunction with this parameter to change the collection element to <wfs:FeatureCollection>.
Note  <wfs:FeatureCollection> is not supported when writing in GML v3.2.1 mode.
  • target-namespace – Changes the root element to <[target-ns-prefix]:FeatureCollection>, where [target-ns-prefix] is the prefix that is bound to the output document target namespace, e.g., <fme:FeatureCollection>. The output xsd document will also include a custom FeatureCollection declaration and FeatureCollectionType definition.

Feature Collection and the Application Schema Parameter

This parameter can also be used to specify the local-name of the element that should be used as the feature collection when used in conjunction with Application Schema. The specified feature collection must exist in the set of parsed schemas, otherwise FeatureCollection in the GML namespace will be assumed.

If the parameter is left empty and if the parent/child relationship for the features in the writer are assembled into several rooted trees, then FeatureCollection will be assumed as the wrapper collection; parent/child relationships are maintained with the gml_id and gml_parent_id attributes.

Note   An XML document must have a single rooted element.

If the parameter has the local-name of the element and this element corresponds to a feature collection in the set parsed schemas, and:
  • if the specified collection is passed in as a feature, then the writer will use this feature as the feature collection of the dataset. The parent/child relationships should be set up so that this feature ends up as the single rooted element of the output. If the single rooted tree does not have the same element name as the specified feature collection, then the writer will automatically create the specified feature collection to serve as the root element of the GML output. Note that the writer will also force any features without a gml_parent_id to be children of the specified collection. This means that users may skip the extra step of assigning a gml_parent_id to all features belonging to that collection.
 OR
  • if the specified collection is NOT passed in as a feature, then the writer will automatically create the specified feature collection to serve as the root element of the GML output. Note that this may not be ideal, as the feature collection may have some required properties that the GML writer cannot automatically populate.

This parameter allows you to supply a custom gml:id value to replace UUID that is automatically assigned for the feature collection under GML v3.2.1.

This parameter is used to specify the XML Namespace URI for the element name that is specified as the feature collection in the Feature Collection parameter.

For example, to specify the WFS 2.0 "FeatureCollection", set this parameter to http://www.opengis.net/wfs/2.0 and Feature Collection to FeatureCollection (as specified above, in Feature Collection when GML Version is Application Schema).

Feature Properties

Specifies whether the default and optional GML feature properties, name and description, should be read.

The FME feature type and/or attribute names may include the XML Namespace prefixes used in the GML application schema. The prefix will be separated from the names with an underscore.

By default, the prefixes are not added to the names. To include the prefixes in the feature types, select Feature Types. To include the prefixes in both the feature types and attributes select Feature Types and Attributes.

Setting this parameter to Feature Types is necessary when a GML dataset contains feature types with the same name in different namespaces.

Advanced

Specify the maximum number of decimal places to write to the GML file when writing coordinates.

To specify an exact number of decimal places to write, use this parameter in conjunction with the Minimum Decimal Places parameter.

Value

An integer greater than or equal to 0.

Default value: 15

Specify the minimum number of decimal place write to the GML file when writing coordinates.

To specify an exact number of decimal places to write, use this parameter in conjunction with the Maximum Decimal Places parameter.

Value

An integer greater than or equal to 0.

Default value: 0

This parameter suppresses the output of the xsi:schemaLocation attribute in the GML instance’s root element. The xsi:schemaLocation in an XML document instance is not a mandatory attribute – it is merely a hint that an XML processor may choose to ignore.

Setting this parameter to Yes suppresses the output of the xsi:schemaLocation attribute in the output GML instance. The default setting is No.

The legal values for this parameter are whitespace-separated XML namespace declarations as they would appear in an XML element.

When an Application Schema mode is not selected, this parameter allows elements in different namespaces, other than the GML and the document target namespace, to be included in the output file. A schema file is not written when this parameter is used – that is, the output XSD file is suppressed. To control the namespace of a particular element, the FME feature type and/or attribute name must carry the corresponding namespace prefixes declared by this parameter.

When an Application Schema mode is selected, this parameter allows different namespace declarations other the ones extracted from the parsed XSD documents be used in the output document. The parameter may be used to control prefixes (for example, to use the default namespace), and also to trim the number of namespace declarations written to the top level element.

One use of this namespace declaration parameter is to set the default namespace in order to remove the namespace prefix from the element names.

For example, consider <gn:NamedPlace>. To remove the gn namespace prefix, you will have to make the namespace associated with gn the default namespace. Looking at the namespace header of the default output, you will see that:

xmlns:gn="urn:x-inspire:specification:gmlas:GeographicalNames:3.0"

To remove this namespace, you will have to set Override XSD and Use Namespace Declarations to: xmlns="urn:x-inspire:specification:gmlas:GeographicalNames:3.0"

Thereafter, the output will contain <NamedPlace>, not <gn:NamedPlace>.

Determines if FME writes the Geometries as a gml:Polygon or a gml:PolygonPatch.

  • No (default value): prints out gml:Surface geometries.
  • Yes: FME creates the geometry as a gml:Polygon in the output.

This optional parameter performs validation of the output file against the schemas referenced in that file:

is set to the XML Namespace URI http://www.ordnancesurvey.co.uk/xml/namespaces/osgb, the schema used for validating the output file is determined by the URI

Yes:

  • If OS MasterMap GML Version is set to the XML Namespace URI http://www.ordnancesurvey.co.uk/xml/namespaces/osgb, the schema used for validating the output file is determined by the URI.
  • If OS MasterMap GML Version is set to Other, the specified Application Schema is used for validation.

No (default):

  • Validation is not performed.

A gml_id geometry trait, if present, is used to populate the gml:id attribute of a GML geometry element. For example, an FME Point with the gml_id trait will be written as <gml:Point gml:id="…">.

  • Yes – A gml:id will be automatically generated for GML geometries without a corresponding gml_id geometry trait.
  • No – This is the default value.

By default, the URL for the target namespace URI-URL location pair in the instance document’s xsi:schemaLocation attribute is the GML application schema’s relative filename. This parameter allows you to overwrite the .xsd filename by supplying a custom URL.

The parameter only affects the value of the URL for the target namespace in the xsi:schemaLocation. It does not affect where the application schema will be written (for this, see the Application Schema parameter). The parameter should have exactly one URL value indicating the XSD location for the target namespace URI.

If the parameter has multiple values, then they must be whitespace-separated URI–URL pairs. This option allows the user to provide a complete custom xsi:schemaLocation for the output document.

Example:

http://www.conurl/ns.xsd

Specifies the encoding to use for the output XML documents, which include both the GML instance and the GML application schema.

If this parameter is left blank, the value UTF-8 will be used.

Use Network Authentication

Note  This parameter is always visible in some formats, and visible in other formats only when the dataset is a URL.

Authentication Method

Specify the authentication method to use when accessing a password-protected server.

  • Basic (default) – Basic access authentication is designed to allow a client to provide credentials to a server on the assumption that the connection between them is trusted and secure. Note that any credentials passed from client to server can be easily intercepted through an insecure connection.
  • Digest – Digest authentication is one of the agreed-upon methods a web server can use to negotiate credentials, such as username or password, with a user's web browser.
  • NTLM – A challenge-response protocol that is used to provide compatibility with versions of Windows earlier than the Windows 2000 operating systems.
  • Web Connection – Web connections provide a convenient and secure way to store and reuse previously established connection parameters. See Web Connection below.
  • Single Sign-on – FME will use the credentials of the current user to authenticate the HTTP request. This authentication method currently works only on the Windows operating system.
Note  To access datasets using a proxy server, use the Network tools in FME Options. From the FME Workbench menu, select Tools > FME Options > Network. For more information, see "Network Proxy" in FME Workbench Help.

Web Connection

Using Web Connections

FME Options: Web Connections