SOSI GML Writer Parameters

SOSI GML Themes

  • by Themes(default) – Enables the SOSI GML Themes parameter.
  • by XSD – Enables the Application Schema parameter, where you can specify a different schema (other than the built-in themes).

Browse a list of the available SOSI GML themes. (Note that themes are based on the v4.6 schemas.)

Note  An explicit path to a different SOSI GML schema with the definitions for the appropriate theme or layer can be specified in 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.

Pretty Printing

Setting this parameter to Yes ensures the output is neatly formatted. This promotes easier reading on screen and in print output. Note, however, that it also produces a considerably larger output file size due to the added whitespace.

  • 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.

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.

This parameter controls whether XML Namespace prefixes are applied to feature types, attributes, or both. The prefix will be separated from the names by an underscore.

  • Feature Types – Includes the prefixes in the feature types. Setting this parameter to Feature Types is necessary if the XSD Schemas contains feature types with the same name in different namespaces.
  • Feature Types (On Conflict) – Includes the prefixes in feature types only when the XSD Schemas contain feature types with the same name in different namespaces.
  • Feature Types and Attributes – Includes the prefixes in both the feature types and attributes.
Note  By default, this reader/writer does not add prefixes to the names.

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.

Feature Properties – Attribute Handling

Specifies whether GML properties that are defined as a complex type with complex content (that is, those that have embedded child elements) should be expanded into Nested Attributes within FME features, or stored as XML Fragments.

  • If set to XML Fragments, complex properties are not expanded. Instead, their entire content is stored as XML text within a single attribute. This produces smaller, simpler feature structures and is suitable when detailed access to individual child elements is not needed.
  • If set to Nested Attributes, complex properties are expanded into nested list attributes wherever possible, exposing their child elements directly as FME attributes. This option is useful when detailed access to individual elements or values is required for mapping or transformation, although it can produce large or deeply nested attribute structures.

When using Nested Attributes, some complex properties that contain embedded objects or geometry elements may still be stored as XML fragments, depending on schema structure or other mapping limits.

Certain complex properties, such as those that are recursively defined or that would otherwise cause circular references, are always mapped as XML fragments regardless of this setting.

This optional parameter applies only when Map Complex Properties As is set to Nested Attributes. It limits how many consecutive levels of multivalued nested list attributes (for example, lists within lists) are preserved before deeper levels are converted into XML fragments.

When the nesting of list elements exceeds this number, expansion automatically stops at that level and deeper content is stored as XML fragments. This helps prevent extremely deep or repetitive data hierarchies from consuming excessive memory or producing unwieldy nested attribute structures.

If this parameter is not specified, all levels of nested lists are expanded up to the general safety limits. Setting a lower value restricts expansion to shallower lists, while a higher value allows deeper nesting at the cost of larger, more complex features.

Note  A value of 0 disables depth-based truncation but does not make this setting behave the same as setting Map Complex Properties As to XML Fragments. When Limit Number of Lists in Nested Attributes is set to 0, complex properties that contain embedded objects or geometry elements may be stored as XML fragments if those elements occur beyond the current nesting depth, so their embedded geometries or objects are not interpreted. Using a higher limit allows traversal to reach these deeper elements, enabling their geometry or object content to be recognized and mapped before any limits are applied. In contrast, setting Map Complex Properties As to XML Fragments stores all complex properties as XML text after any embedded geometries or objects have been interpreted.

Spatial

Coordinate systems may be extracted from input feature data sources, may come predefined with FME, or may be user-defined. FME allows different output and input coordinate systems, and performs the required coordinate conversions when necessary.

How FME Processes Coordinate Systems in the Workspace

If a coordinate system is specified in both the source format and the workspace, the coordinate system in the workspace is used. The coordinate system specified in the source format is not used, and a warning is logged. If a source coordinate system is not specified in the workspace and the format or system does not store coordinate system information, then the coordinate system is not set for the features that are read.

If a destination coordinate system is set and the feature has been tagged with a coordinate system, then a coordinate system conversion is performed to put the feature into the destination system. This happens right before the feature enters into the writer.

If the destination coordinate system was not set, then the features are written out in their original coordinate system.

If a destination coordinate system is set, but the source coordinate system was not specified in the workspace or stored in the source format, then no conversion is performed. The features are simply tagged with the output system name before being written to the output dataset.

For systems that know their coordinate system, the Coordinate System field will display Read from Source and FME will read the coordinate system from the source dataset. For most other input sources, the field will display Unknown (which simply means that FME will use default values). In most cases, the default value is all you'll need to perform the translation.

You can always choose to override the defaults and choose a new coordinate system. Select More Coordinate Systems from the drop-down menu to open the Coordinate System Gallery.

Changing a Reprojection

To perform a reprojection, FME typically uses the CS-MAP reprojection engine, which includes definitions for thousands of coordinate systems, with a large variety of projections, datums, ellipsoids, and units. However, GIS applications have slightly different algorithms for reprojecting data between different coordinate systems. To ensure that the data FME writes matches exactly to your existing data, you can use the reprojection engine from a different application.

Note  To use this feature, you must have a supported GIS application installed on your system (for example, Esri ArcGIS®).

To change the reprojection engine, Select Workspace Parameters > Spatial > Reprojection Engine. In the example shown, you can select Esri (but the selection here depends on your installed applications):

For more information, see the links below:

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.

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>.

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

Yes:

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 application schema’s relative filename. This parameter allows you to overwrite the .xsd filename by supplying a custom URL.

The parameter affects only the value of the URL for the target namespace in the xsi:schemaLocation. It does not affect where the application schema will be written. The parameter should have exactly one URL value indicating the XSD location for the target namespace URI. For example:

http://www.conurl/ns.xsd

To add multiple values, they must be whitespace-separated URI–URL pairs. This option allows you to provide a complete custom xsi:schemaLocation for the output document.

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 Utilities > FME Options > Network Proxy. For more information, see Network Proxy in FME Workbench Help.

Web Connection

Using Web Connections

FME Options: Web Connections