Supported GML Versions¶

Secondary namespace for GML 3.2.1 required¶

GML 3.2.1 WFS responses are delivered in a WFS 2.0.0 FeatureCollection. Unlike WFS 1.1.0, WFS 2.0.0 does not depend explicitly on any GML version. As a consequence, the GML namespace is secondary and must be defined explicitly as a secondary namespace. See Secondary Namespaces for details.

For example, to use the prefix gml for GML 3.2, create workspaces/gml/namespace.xml containing:

<namespace>
    <id>gml_namespace</id>
    <prefix>gml</prefix>
    <uri>http://www.opengis.net/gml/3.2</uri>
</namespace>

and workspaces/gml/workspace.xml containing:

<workspace>
    <id>gml_workspace</id>
    <name>gml</name>
</workspace>

Failure to define the gml namespace prefix with a secondary namespace will result in errors like:

java.io.IOException: The prefix "null" for element "null:name" is not bound.

while encoding a response (in this case one containing gml:name), even if the namespace prefix is defined in the mapping file.

GML 3.2.1 geometries require gml:id¶

GML 3.2.1 requires that all geometries have a gml:id. While GeoServer will happily encode WFS responses without gml:id on geometries, these will be schema-invalid. Encoding a gml:id on a geometry can be achieved by setting an idExpression in the mapping for the geometry property. For example, gsml:shape is a geometry property and its gml:id might be generated with:

<AttributeMapping>
    <targetAttribute>gsml:shape</targetAttribute>
    <idExpression>
        <OCQL>strConcat('shape.', getId())</OCQL>
    </idExpression>
    <sourceExpression>
        <OCQL>SHAPE</OCQL>
    </sourceExpression>
</AttributeMapping>

In this example, getId() returns the gml:id of the containing feature, so each geometry will have a unique gml:id formed by appending the gml:id of the containing feature to the string "shape.".

If a multigeometry (such as a MultiPoint or MultiSurface) is assigned a gml:id of (for example) parentid, to permit GML 3.2.1 schema-validity, each geometry that the multigeometry contains will be automatically assigned a gml:id of the form parentid.1, parentid.2, … in order.