Hi All, At the bottom of this email is an extract from an W3C XML Schema file. When I try to validate this XSD I get the following error: "E src-resolve: Cannot resolve the name 'gml:AbstractGeometryType' to a(n) 'type definition' component." The line to which this errors refers is: " <xs:element name="TM_Object" type="gml:AbstractTimeObjectType"/>" I'm not quite sure what this error message means. I have tried looking at the relevant W3C XML Schema documentation but it doesn't make sense to me. I have looked at the temporal.xsd, which is the file referred to by the "gml" namespace. The relevant code looks like this: " <complexType name="AbstractTimeObjectType" abstract="true"> <annotation> <documentation xml:lang="en"> The abstract supertype for temporal objects. </documentation> </annotation> <complexContent> <extension base="gml:AbstractGMLType"/> </complexContent> </complexType> " All I can think of is that the complexType name mentioned above should be "gml:AbstractTimeObjectType" to make it relate to the "gml" namespace. Can anyone tell me how I must change the code below to get rid of the error? Thanks in advance for any help. John <?xml version="1.0" encoding="UTF-8"?> <xs:schema targetNamespace="http://www.isotc211.org/stXML" xmlns:stXML="http://www.isotc211.org/stXML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:scXML="http://www.isotc211.org/scXML" xmlns:gml="http://www.opengis.net/gml" version="0.1"> <!-- ================================== Imports ================================== --> <xs:import namespace="http://www.opengis.net/gml" schemaLocation="../../GML3.1/GML-3.1.0-Draft-Schemas/base/temporal.xsd"/> <xs:import namespace="http://www.isotc211.org/scXML" schemaLocation="basicTypes.xsd"/> <!-- ================================== Classes ================================= --> <!-- ........................................................................ --> <xs:element name="TM_Primitive" type="gml:AbstractTimePrimitiveType" substitutionGroup="stXML:TM_Object"/> <!-- ........................................................................ --> <xs:complexType name="TM_Primitive_PropertyType"> <xs:sequence> <xs:element ref="gml:_TimePrimitive" minOccurs="0"/> </xs:sequence> <xs:attributeGroup ref="scXML:ObjectReference"/> </xs:complexType> <!-- =========================================================================== --> <!-- ........................................................................ --> <xs:element name="TM_Object" type="gml:AbstractTimeObjectType"/> <!-- ........................................................................ --> <xs:complexType name="TM_Object_PropertyType"> <xs:sequence> <xs:element ref="gml:_TimeObject" minOccurs="0"/> </xs:sequence> <xs:attributeGroup ref="scXML:ObjectReference"/> </xs:complexType>