<?xml version="1.0" encoding="UTF-8"?>
<!--W3C Schema for VOTable  = Virtual Observatory Tabular Format
.Version 1.0 : 15-Apr-2002
.Version 1.09: 23-Jan-2004 Version 1.09
.Version 1.09: 30-Jan-2004 Version 1.091
.Version 1.09: 22-Mar-2004 Version 1.092
.Version 1.094: 02-Jun-2004 GROUP does not contain FIELD
.Version 1.1 :  10-Jun-2004 remove the complexContent
-->
<xs:schema 
   xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"
   targetNamespace="http://www.ivoa.net/xml/VOTable/v1.1" 
   xmlns="http://www.ivoa.net/xml/VOTable/v1.1"
>

<!-- Here we define some interesting new datatypes:
     - anyTEXT   may have embedded XHTML (conforming HTML)
     - astroYear is an epoch in Besselian or Julian year, e.g. J2000
     - arrayDEF  specifies an array size e.g. 12x23x*
     - dataType  defines the acceptable datatypes
     - ucdType   defines the acceptable UCDs (UCD1+)
     - precType  defines the acceptable precisions
     - yesno     defines just the 2 alternatives
-->

<xs:complexType name="anyTEXT" mixed="true">
      <xs:sequence>
        <xs:any minOccurs="0" maxOccurs="unbounded" processContents="skip"/>
      </xs:sequence>
</xs:complexType>

<xs:simpleType  name="astroYear">
  <xs:restriction base="xs:token">
    <xs:pattern  value="[JB]?[0-9]+([.][0-9]*)?"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType  name="ucdType">
  <xs:restriction base="xs:token">
    <xs:pattern  value="[A-Za-z0-9_.;\-]*"/><!-- UCD1 use also / + % -->
  </xs:restriction>
</xs:simpleType>

<xs:simpleType  name="arrayDEF">
  <xs:restriction base="xs:token">
    <xs:pattern  value="([0-9]+x)*[0-9]*[*]?(s\W)?"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType  name="encodingType">
  <xs:restriction base="xs:NMTOKEN">
    <xs:enumeration value="gzip"/>
    <xs:enumeration value="base64"/>
    <xs:enumeration value="dynamic"/>
    <xs:enumeration value="none"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="dataType">
  <xs:restriction base="xs:NMTOKEN">
    <xs:enumeration value="boolean"/>
    <xs:enumeration value="bit"/>
    <xs:enumeration value="unsignedByte"/>
    <xs:enumeration value="short"/>
    <xs:enumeration value="int"/>
    <xs:enumeration value="long"/>
    <xs:enumeration value="char"/>
    <xs:enumeration value="unicodeChar"/>
    <xs:enumeration value="float"/>
    <xs:enumeration value="double"/>
    <xs:enumeration value="floatComplex"/>
    <xs:enumeration value="doubleComplex"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="precType">
  <xs:restriction base="xs:token">
    <xs:pattern value="[EF]?[1-9][0-9]*"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="yesno">
  <xs:restriction base="xs:NMTOKEN">
    <xs:enumeration value="yes"/>
    <xs:enumeration value="no"/>
  </xs:restriction>
</xs:simpleType>

<!-- VOTable is the root element -->
  <xs:element name="VOTABLE">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="DESCRIPTION" minOccurs="0"/>
        <xs:element ref="DEFINITIONS" minOccurs="0"/><!-- Deprecated -->
	<xs:choice minOccurs="0" maxOccurs="unbounded">
          <xs:element ref="COOSYS" />
          <xs:element ref="PARAM"  />
          <xs:element ref="INFO"   />
	</xs:choice>
        <xs:element ref="RESOURCE" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="ID" type="xs:ID"/>
      <xs:attribute name="version">
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="1.1"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
    </xs:complexType>
  </xs:element>

<!-- RESOURCES can contain DESCRIPTION, (INFO|PARAM|COSYS), LINK, TABLEs -->
  <xs:element name="RESOURCE">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="DESCRIPTION" minOccurs="0"/>
	<xs:choice minOccurs="0" maxOccurs="unbounded">
          <xs:element ref="INFO" />
          <xs:element ref="COOSYS" />
          <xs:element ref="PARAM"  />
	</xs:choice>
        <xs:element ref="LINK" minOccurs="0" maxOccurs="unbounded"/>
        <xs:element ref="TABLE" minOccurs="0" maxOccurs="unbounded"/>
        <xs:element ref="RESOURCE" minOccurs="0" maxOccurs="unbounded"/>
	<!-- Suggested Doug Tody, to include new RESOURCE types -->
	<xs:any namespace="##other" processContents="lax"
	    minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="name" type="xs:token"/>
      <xs:attribute name="ID"   type="xs:ID"/>
      <xs:attribute name="utype" type="xs:string"/>
      <xs:attribute name="type" default="results">
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="results"/>
            <xs:enumeration value="meta"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
      <!-- Suggested Doug Tody, to include new RESOURCE attributes -->
      <xs:anyAttribute namespace="##other" processContents="lax"/>
    </xs:complexType>
  </xs:element>

  <xs:element name="DESCRIPTION" type="anyTEXT" />

  <xs:element name="DEFINITIONS">
  <xs:annotation>
    <xs:documentation>Deprecated in Version 1.1</xs:documentation>
  </xs:annotation>
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element ref="COOSYS" />
        <xs:element ref="PARAM" />
      </xs:choice>
    </xs:complexType>
  </xs:element>

<!-- INFO is a name-value pair -->
  <xs:element name="INFO">
    <xs:complexType><xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute name="ID" type="xs:ID"/>
        <xs:attribute name="name" type="xs:token" use="required"/>
        <xs:attribute name="value" type="xs:string" use="required"/>
      </xs:extension>
    </xs:simpleContent></xs:complexType>
  </xs:element>

<!-- A PARAM is similar to a FIELD, but it also has a "value" attribute -->
  <xs:element name="PARAM">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="DESCRIPTION" minOccurs="0"/>
        <xs:element ref="VALUES" minOccurs="0"/>
        <xs:element ref="LINK" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="ID" type="xs:ID"/>
      <xs:attribute name="unit" type="xs:token"/>
      <xs:attribute name="datatype" type="dataType" use="required"/>
      <xs:attribute name="precision" type="precType"/>
      <xs:attribute name="width" type="xs:positiveInteger"/>
      <xs:attribute name="ref" type="xs:IDREF"/>
      <xs:attribute name="name" type="xs:token" use="required"/>
      <xs:attribute name="ucd" type="ucdType"/>
      <xs:attribute name="utype" type="xs:string"/>
      <xs:attribute name="value" type="xs:string" use="required"/>
      <xs:attribute name="arraysize" type="arrayDEF"/>
    </xs:complexType>
  </xs:element>

<!-- A TABLE is a sequence of FIELD/PARAMs and LINKS and DESCRIPTION, 
     possibly followed by a DATA section 
-->
  <xs:element name="TABLE">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="DESCRIPTION" minOccurs="0"/>
	<xs:choice minOccurs="0" maxOccurs="unbounded">
          <xs:element ref="FIELD" />
          <xs:element ref="PARAM" />
          <xs:element ref="GROUP" />
	</xs:choice>
        <xs:element ref="LINK" minOccurs="0" maxOccurs="unbounded"/>
        <xs:element ref="DATA" minOccurs="0"/>
      </xs:sequence>
      <xs:attribute name="ID"   type="xs:ID"/>
      <xs:attribute name="name" type="xs:token"/>
      <xs:attribute name="ref"  type="xs:IDREF"/>
      <xs:attribute name="ucd"  type="ucdType"/>
      <xs:attribute name="utype" type="xs:string"/>
      <xs:attribute name="nrows" type="xs:nonNegativeInteger"/>
    </xs:complexType>
  </xs:element>

<!-- FIELD is the definition of what is in a column of the table -->
  <xs:element name="FIELD">
    <xs:complexType>
      <xs:sequence> <!-- minOccurs="0" maxOccurs="unbounded" -->
        <xs:element ref="DESCRIPTION" minOccurs="0"/>
        <xs:element ref="VALUES" minOccurs="0"/> <!-- maxOccurs="2" -->
        <xs:element ref="LINK" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="ID" type="xs:ID"/>
      <xs:attribute name="unit" type="xs:token"/>
      <xs:attribute name="datatype" type="dataType" use="required"/>
      <xs:attribute name="precision" type="precType"/>
      <xs:attribute name="width" type="xs:positiveInteger"/>
      <xs:attribute name="ref" type="xs:IDREF"/>
      <xs:attribute name="name" type="xs:token" use="required"/>
      <xs:attribute name="ucd" type="ucdType"/>
      <xs:attribute name="utype" type="xs:string"/>
      <xs:attribute name="arraysize" type="xs:string"/>
      <xs:attribute name="type">
	<!-- type is not in the Version 1.1, but is kept for
	     backward compatibility purposes
	-->
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="hidden"/>
            <xs:enumeration value="no_query"/>
            <xs:enumeration value="trigger"/>
            <xs:enumeration value="location"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
    </xs:complexType>
  </xs:element>

<!-- GROUP groups columns; may include descriptions, fields/params/groups -->
  <xs:element name="GROUP">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="DESCRIPTION" minOccurs="0"/>
        <xs:choice minOccurs="0" maxOccurs="unbounded">
	  <xs:element ref="FIELDref"/>
	  <xs:element ref="PARAMref"/>
	  <xs:element ref="PARAM"/>
	  <xs:element ref="GROUP"/>
        </xs:choice>
      </xs:sequence>
      <xs:attribute name="ID"   type="xs:ID"/>
      <xs:attribute name="name" type="xs:token"/>
      <xs:attribute name="ref"  type="xs:IDREF"/>
      <xs:attribute name="ucd"  type="ucdType"/>
      <xs:attribute name="utype" type="xs:string"/>
    </xs:complexType>
  </xs:element>

<!-- FIELDref and PARAMref are references to FIELD or PARAM defined
     in the parent TABLE or RESOURCE -->
  <xs:element name="FIELDref">
    <xs:complexType>
      <xs:attribute name="ref" type="xs:IDREF" use="required"/>
      <!-- utype and maybe ucd could well be added there,
	   will be if necessary -->
    </xs:complexType>
  </xs:element>
  <xs:element name="PARAMref">
    <xs:complexType>
      <xs:attribute name="ref" type="xs:IDREF" use="required"/>
      <!-- utype and maybe ucd could well be added there,
	   will be if necessary -->
    </xs:complexType>
  </xs:element>
    
<!-- VALUES expresses the values that can be taken by the data 
     in a column or by a parameter
-->
  <xs:element name="VALUES">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="MIN" minOccurs="0"/>
        <xs:element ref="MAX" minOccurs="0"/>
        <xs:element ref="OPTION" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="ID" type="xs:ID"/>
      <xs:attribute name="type" default="legal">
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="legal"/>
            <xs:enumeration value="actual"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name="null" type="xs:token"/>
      <xs:attribute name="ref"  type="xs:IDREF"/>
      <!-- xs:attribute name="invalid" type="yesno" default="no"/ -->
    </xs:complexType>
  </xs:element>
  <xs:element name="MIN">
    <xs:complexType>
      <xs:attribute name="value" type="xs:string" use="required"/>
      <xs:attribute name="inclusive" type="yesno" default="yes"/>
    </xs:complexType>
  </xs:element>
  <xs:element name="MAX">
    <xs:complexType>
      <xs:attribute name="value" type="xs:string" use="required"/>
      <xs:attribute name="inclusive" type="yesno" default="yes"/>
    </xs:complexType>
  </xs:element>
  <xs:element name="OPTION">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="OPTION" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="name" type="xs:token"/>
      <xs:attribute name="value" type="xs:string" use="required"/>
    </xs:complexType>
  </xs:element>

<!-- The LINK is a URL (href) or some other kind of reference (gref) -->
  <xs:element name="LINK">
    <xs:complexType mixed="true">
      <xs:attribute name="ID" type="xs:ID"/>
      <xs:attribute name="content-role">
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="query"/>
            <xs:enumeration value="hints"/>
            <xs:enumeration value="doc"/>
            <xs:enumeration value="location"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name="content-type" type="xs:token"/>
      <xs:attribute name="title" type="xs:string"/>
      <xs:attribute name="value" type="xs:string"/>
      <xs:attribute name="href" type="xs:anyURI"/>
      <xs:attribute name="gref" type="xs:token"/><!-- Deprecated in V1.1 -->
      <xs:attribute name="action" type="xs:anyURI"/>
    </xs:complexType>
  </xs:element>

<!-- DATA is the actual table data, in one of three formats -->
  <xs:element name="DATA">
    <xs:complexType>
      <xs:choice>
        <xs:element ref="TABLEDATA"/>
        <xs:element ref="BINARY"/>
        <xs:element ref="FITS"/>
      </xs:choice>
    </xs:complexType>
  </xs:element>

<!-- Pure XML data -->
  <xs:element name="TABLEDATA">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="TR" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="TD">
    <xs:complexType><xs:simpleContent>
      <xs:extension base="xs:string">
        <!-- xs:attribute name="ref" type="xs:IDREF"/ -->
        <xs:attribute name="encoding" type="encodingType"/>
      </xs:extension>
    </xs:simpleContent></xs:complexType>
  </xs:element>

  <xs:element name="TR">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="TD" maxOccurs="unbounded"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

<!-- FITS file, perhaps with specification of which extension to seek to -->
  <xs:element name="FITS">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="STREAM"/>
      </xs:sequence>
      <xs:attribute name="extnum" type="xs:positiveInteger"/>
    </xs:complexType>
  </xs:element>

<!-- BINARY data format -->
  <xs:element name="BINARY">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="STREAM"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

<!-- STREAM can be local or remote, encoded or not -->
  <xs:element name="STREAM">
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base="xs:string">
          <xs:attribute name="type" default="locator">
            <xs:simpleType>
              <xs:restriction base="xs:NMTOKEN">
                <xs:enumeration value="locator"/>
                <xs:enumeration value="other"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
          <xs:attribute name="href" type="xs:anyURI"/>
          <xs:attribute name="actuate" default="onRequest">
            <xs:simpleType>
              <xs:restriction base="xs:NMTOKEN">
                <xs:enumeration value="onLoad"/>
                <xs:enumeration value="onRequest"/>
                <xs:enumeration value="other"/>
                <xs:enumeration value="none"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
          <xs:attribute name="encoding" type="encodingType" default="none"/>
          <xs:attribute name="expires" type="xs:dateTime"/>
          <xs:attribute name="rights" type="xs:token"/>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>

<!-- Expresses the coordinate system we are using -->
  <xs:element name="COOSYS">
    <xs:complexType><xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute name="ID" type="xs:ID" use="required"/>
        <xs:attribute name="equinox" type="astroYear"/>
        <xs:attribute name="epoch" type="astroYear"/>
        <xs:attribute name="system" default="eq_FK5">
          <xs:simpleType>
            <xs:restriction base="xs:NMTOKEN">
              <xs:enumeration value="eq_FK4"/>
              <xs:enumeration value="eq_FK5"/>
              <xs:enumeration value="ICRS"/>
              <xs:enumeration value="ecl_FK4"/>
              <xs:enumeration value="ecl_FK5"/>
              <xs:enumeration value="galactic"/>
              <xs:enumeration value="supergalactic"/>
              <xs:enumeration value="xy"/>
              <xs:enumeration value="barycentric"/>
              <xs:enumeration value="geo_app"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
      </xs:extension></xs:simpleContent></xs:complexType>
  </xs:element>

</xs:schema>
