OGC GML Writer Parameters

The GML writer can write a dataset according to an existing GML Application Schema, or create the GML Application Schema along with the written dataset.

The GML Application Schema option is used in conjunction with the Application Schema parameter. The resulting GML Application Schema mode allows the writer to write GML datasets according to existing GML-based standard formats such as AIXM v5.1 or INSPIRE.

The Application Schema parameter is used to specify the appropriate XML Schema document.

Setting the parameter to either 3.1.1 or 3.2.1 instructs the writer to create an XSD that is based on the writer feature type definitions. A new XSD document will be created every time.

Note: The GML writer will not write to an existing GML-based standard such as AIXM v5 or INSPIRE in this mode.

Specifies the location of the GML Application Schema .xsd document.

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.

Setting this parameter to Yes allows GML geometry xlink references to be written. The corresponding FME geometry must have a non empty xlink_href trait.

For example, if a surface component, such as a Face in a Composite Surface, has an xlink_href trait with value #GML_d3981803-d4b0-4b5b-969c-53f657594757, then the writer will produce the following geometry reference:

<gml:surfaceMember xlink:href="#GML_d3981803-d4b0-4b5b-969c-53f657594757"/>

Including the gml_orientation boolean trait with a "-" or "+" value along with the xlink_href trait causes the writer to output an OrientableSurface with a base surface geometry reference. For example:

<gml:surfaceMember>

<gml:OrientableSurface orientation="-">

<gml:baseSurface xlink:href="#GML_d3981803-d4b0-4b5b-969c-53f657594757"/>

</gml:OrientableSurface>

</gml:surfaceMember>

The directive specifies the GML application schema target namespace prefix. The default value for this directive is fme.

This parameter specifies the GML application schema target namespace URI. The default value for this parameter is http://www.safe.com/gml/fme.

Note that a URI is a label only (usually an ownership identifier), and the XML Namespace specification does not require that the URI be used for information retrieval. Using a URI (rather than a simple string) to identify a namespace reduces the probability of different namespaces having duplicate identifiers.

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.

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.

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 the "FeatureCollection" (as specified above, in Feature Collection when GML Version is Application Schema).

This parameter specifies how embedded GML objects (those containing a gml:id), that are not geometries should be mapped.

By default, these embedded objects are mapped into FME Attributes.

If the parameter is set to Geometries, the embedded objects are mapped into FME Geometries, and the embedded object properties are loaded into geometric traits. In turn, nested embedded objects are mapped into nested aggregate geometries.

If the parameter is set to Feature Types, the embedded objects will be mapped into separate FME feature types, and these feature types will have an additional gml_parent_id attribute whose value refers back to its parent feature.

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

The GML writer will automatically substitute concrete elements that are substitutable for abstract GML properties. Some GML formats declare properties that are not abstract but are nevertheless head of substitution groups.

Selecting this parameter instructs the GML writer to also generate FME attributes for member elements belonging to the substitution group headed by these non-abstract GML properties.

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.

There are many different feature types with many possible geometries per feature type.

Nameless geometries are ignored by writers in Application Schema mode because they do not correspond to any properties in the .xsd documents.

When this option is checked, the writer will attempt to write out nameless geometries to geometrically compatible properties.

This parameter specifies whether GML Coverages should be mapped into FME features.

Note: No special geometrical interpretation is attempted with the contents of the GML coverage; therefore, most coverage content will be mapped as nested attribute lists and/or xml fragments.

Specifies whether GML properties that are defined as a complex type with complex content (that is, those that have embedded children elements) should be mapped as nested list attributes within FME features.

If the value is set to XML Fragments, then the complex properties with complex content are mapped as XML fragments.

Some complex properties, such as those that are recursively defined, cannot be mapped as nested lists. These complex properties will always be mapped as XML fragments, regardless of the setting for this parameter.

This optional parameter can control the depth of nested list attributes.

This parameter may be used to optionally specify the XML document that is to be written out as output. Any XML element created from a rooted feature by the writer will be inserted into this document. By default, the XML elements are inserted right before the end tag of the XML document’s root element.

XML Document Append Path

This parameter specifies a single element via a QName, or a path to a single element via a path of QNames, in the XML Document.

Each element in the path is separated by a forward slash (/). An asterisk wildcard (*) may also be used as the prefix or local-name of the element’s QName. For example, *:e, p:*, or just * (which is a shorter version of *:*).

This parameter specifies a single insertion point in the XML Document. To append into multiple sections, use the xml_document_append_path format attribute – this format attribute overrides this parameter if present.

XML Document Append As

This parameter controls how the features that are mapped into XML are inserted into the XML Document in relation to the XML Document Append Path.

The possible values for the parameter are:

• Succeeding Children (default)
• Preceding Children
• Preceding Siblings
• Succeeding Siblings

The values are to be understood in relation to the selected or matched element.

Each individual root feature may override this parameter by using the xml_document_append_as format attribute. The possible values for xml_document_append_as are preceding_children, succeeding_children, preceding_siblings, and succeeding_siblings.

Note: To dynamically control the contents of the XML Document (for example, to be able to generate its contents within the workspace with an XMLTemplater transformer), you can add a special writer feature type – _XML_DOCUMENT_ – whose xml_document, xml_document_append_path, and xml_document_append_as format attributes (if present) overwrite their corresponding writer’s parameter values. The possible values for xml_document_append_as are preceding_children, succeeding_children, preceding_siblings, and succeeding_siblings.

Note: XML Fragments having no corresponding feature types may be appended to the XML Document via the special writer feature type – _XML_FRAGMENT_ – the xml fragment is specified with the xml_fragment attribute. The xml_document_append_path, and xml_document_append_as format attributes specify where and how the fragment is appended in the XML Document.

This parameter may be used to optionally specify a wrapper XML fragment for the XML elements that are created from the XSD Schema.

Each individual feature may override this parameter by using the xml_wrapper format attribute.

XML Wrapper Append Path

This parameter specifies a single element via a QName, or a path to a single element via a path of QNames, in the XML Fragment.

Each element in the path is separated by a forward slash (/). An asterisk wildcard (*) may also be used as the prefix or local-name of the element’s QName. For example, *:e, p:*, or just * (which is a shorter version of *:*).

Each individual feature may override this parameter by using the xml_wrapper_append_path format attribute.

XML Wrapper Append As

This parameter controls how the features that are mapped into XML are inserted into the XML Wrapper in relation to the XML Wrapper Append Path.

The possible values for the parameter are:

• Succeeding Children (default)
• Preceding Children
• Preceding Siblings
• Succeeding Siblings

The values are to be understood in relation to the selected or matched element.

• Yes – Every GML writer feature type is translated to the output GML application schema document as an XML Schema element declaration and a corresponding complex type definition.
• No (Default) – Directs the writer to ignore those feature types that have no corresponding feature instances.

Specify the maximum number of decimal place 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 decimal places.

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 decimal places.

Instructs the writer to write out only the .xsd document, only the .gml document, or both documents.

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.

Specify an XSLT stylesheet to be applied to the final output document.

The Stylesheet Result parameter may be used in conjunction with this parameter to specify the location and filename of the resulting transformation.

This parameter is valid only in conjunction with the XSLT Stylesheet to Apply parameter.

When this parameter is not defined, the resulting XSLT transformation will have the same location and filename as the output dataset, with the exception that the filename will be prefixed with transformed_.

This parameter is valid only if XSLT Stylesheet to Apply is specified, and it takes precedence over Stylesheet Result.

Note: This parameter suppresses the XML schema .xsd document for output.

When set to Yes, a temporary file is written in the same folder at the location specified in the writer, the stylesheet is applied to the to temporary file, and the result of the transformation is stored in the output dataset file.

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.

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="…">.

This parameter can be set to Yes or No:

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

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

Yes:

• If GML Version is set to 3.1.1 or 3.2.1, the schema used for validating the output file is determined by the version specified.
• If GML Version is set to GML Application Schema, 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="…">.

This parameter can be set to Yes or No:

• 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.

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 Workbench menu, select Tools > FME Options > Network. For more information, see "Network Proxy" in the FME Workbench Help.

Using Web Connections

FME Options: Web Connections