<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema
   targetNamespace="http://www.opengis.net/ogc"
   xmlns:ogc="http://www.opengis.net/ogc"
   xmlns:gml="http://www.opengis.net/gml"
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"
   elementFormDefault="qualified"
   version="1.1.0">
   <xsd:annotation>
      <xsd:documentation>
         This XML Schema defines OGC query filter capabilities documents.
         Copyright (c) 2002, 2003, 2004 OpenGIS, All Rights Reserved. 
      </xsd:documentation>
   </xsd:annotation>
   <xsd:element name="Filter_Capabilities">
      <xsd:complexType>
         <xsd:sequence>
            <xsd:element name="Spatial_Capabilities"
                         type="ogc:Spatial_CapabilitiesType"/>
            <xsd:element name="Scalar_Capabilities"
                         type="ogc:Scalar_CapabilitiesType"/>
            <xsd:element name="Id_Capabilities"
                         type="ogc:Id_CapabilitiesType"/>
         </xsd:sequence>
      </xsd:complexType>
   </xsd:element>
   <xsd:complexType name="Spatial_CapabilitiesType">
      <xsd:sequence>
         <xsd:element name="GeometryOperands"
                      type="ogc:GeometryOperandsType"/>
         <xsd:element name="SpatialOperators"
                      type="ogc:SpatialOperatorsType"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:complexType name="GeometryOperandsType">
      <xsd:sequence>
         <xsd:element name="GeometryOperand"
                      type="ogc:GeometryOperandType" maxOccurs="unbounded"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:simpleType name="GeometryOperandType">
      <xsd:restriction base="xsd:QName">
         <xsd:enumeration value="gml:Envelope"/>
         <xsd:enumeration value="gml:Point"/>
         <xsd:enumeration value="gml:LineString"/>
         <xsd:enumeration value="gml:Polygon"/>
         <xsd:enumeration value="gml:ArcByCenterPoint"/>
         <xsd:enumeration value="gml:CircleByCenterPoint"/>
         <xsd:enumeration value="gml:Arc"/>
         <xsd:enumeration value="gml:Circle"/>
         <xsd:enumeration value="gml:ArcByBulge"/>
         <xsd:enumeration value="gml:Bezier"/>
         <xsd:enumeration value="gml:Clothoid"/>
         <xsd:enumeration value="gml:CubicSpline"/>
         <xsd:enumeration value="gml:Geodesic"/>
         <xsd:enumeration value="gml:OffsetCurve"/>
         <xsd:enumeration value="gml:Triangle"/>
         <xsd:enumeration value="gml:PolyhedralSurface"/>
         <xsd:enumeration value="gml:TriangulatedSurface"/>
         <xsd:enumeration value="gml:Tin"/>
         <xsd:enumeration value="gml:Solid"/>
      </xsd:restriction>
   </xsd:simpleType>
   <xsd:complexType name="SpatialOperatorsType">
      <xsd:sequence>
         <xsd:element name="SpatialOperator"
                      type="ogc:SpatialOperatorType"
                      maxOccurs="unbounded"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:complexType name="SpatialOperatorType">
      <xsd:sequence>
         <xsd:element name="GeometryOperands"
                      type="ogc:GeometryOperandsType"
                      minOccurs="0"/>
      </xsd:sequence>
      <xsd:attribute name="name" type="ogc:SpatialOperatorNameType"/>
   </xsd:complexType>
   <xsd:simpleType name="SpatialOperatorNameType">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="BBOX"/>
         <xsd:enumeration value="Equals"/>
         <xsd:enumeration value="Disjoint"/>
         <xsd:enumeration value="Intersects"/>
         <xsd:enumeration value="Touches"/>
         <xsd:enumeration value="Crosses"/>
         <xsd:enumeration value="Within"/>
         <xsd:enumeration value="Contains"/>
         <xsd:enumeration value="Overlaps"/>
         <xsd:enumeration value="Beyond"/>
         <xsd:enumeration value="DWithin"/>
      </xsd:restriction>
   </xsd:simpleType>
   <xsd:complexType name="Scalar_CapabilitiesType">
      <xsd:sequence>
         <xsd:element ref="ogc:LogicalOperators"
                      minOccurs="0" maxOccurs="1"/>
         <xsd:element name="ComparisonOperators"
                      type="ogc:ComparisonOperatorsType"
                      minOccurs="0" maxOccurs="1"/>
         <xsd:element name="ArithmeticOperators"
                      type="ogc:ArithmeticOperatorsType"
                      minOccurs="0" maxOccurs="1"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:element name="LogicalOperators">
      <xsd:complexType/>
   </xsd:element>
   <xsd:complexType name="ComparisonOperatorsType">
      <xsd:sequence maxOccurs="unbounded">
         <xsd:element name="ComparisonOperator"
                      type="ogc:ComparisonOperatorType"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:simpleType name="ComparisonOperatorType">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="LessThan"/>
         <xsd:enumeration value="GreaterThan"/>
         <xsd:enumeration value="LessThanEqualTo"/>
         <xsd:enumeration value="GreaterThanEqualTo"/>
         <xsd:enumeration value="EqualTo"/>
         <xsd:enumeration value="NotEqualTo"/>
         <xsd:enumeration value="Like"/>
         <xsd:enumeration value="Between"/>
         <xsd:enumeration value="NullCheck"/>
      </xsd:restriction>
   </xsd:simpleType>
   <xsd:complexType name="ArithmeticOperatorsType">
      <xsd:choice maxOccurs="unbounded">
         <xsd:element ref="ogc:SimpleArithmetic"/>
         <xsd:element name="Functions" type="ogc:FunctionsType"/>
      </xsd:choice>
   </xsd:complexType>
   <xsd:element name="SimpleArithmetic">
      <xsd:complexType/>
   </xsd:element>
   <xsd:complexType name="FunctionsType">
      <xsd:sequence>
         <xsd:element name="FunctionNames" type="ogc:FunctionNamesType"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:complexType name="FunctionNamesType">
      <xsd:sequence maxOccurs="unbounded">
         <xsd:element name="FunctionName" type="ogc:FunctionNameType"/>
      </xsd:sequence>
   </xsd:complexType>
   <xsd:complexType name="FunctionNameType">
      <xsd:simpleContent>
         <xsd:extension base="xsd:string">
            <xsd:attribute name="nArgs" type="xsd:string" use="required"/>
         </xsd:extension>
      </xsd:simpleContent>
   </xsd:complexType>
   <xsd:complexType name="Id_CapabilitiesType">
      <xsd:choice maxOccurs="unbounded">
         <xsd:element ref="ogc:EID"/>
         <xsd:element ref="ogc:FID"/>
      </xsd:choice>
   </xsd:complexType>
   <xsd:element name="EID">
      <xsd:complexType/>
   </xsd:element>
   <xsd:element name="FID">
      <xsd:complexType/>
   </xsd:element>
</xsd:schema>
