CoordinateSystemTypes

<xs:simpleType name="CoordinateSystemTypes">
  <xs:annotation>
    <xs:documentation>
      <P>Standard celestial coordinate systems:
        <UL>
          <LI>ICRS="International Celestial Reference System";</LI>
          <LI>FK4="mean place (old Bessel/Newcomb system)";</LI>
          <LI>FK5="mean place (IAU 1984)";</LI>
          <LI>FK4-no-e="FK4 without e-terms";</LI>
          <LI>GAPPT="Geocentric Apparent Place (IAU 1984)".</LI>
        </UL>See WCS/FITS discussion by Calabretta & Greisen, A&A 395, 1077 (2002). (e.g. http://www.edpsciences.org/articles/aa/full/2002/45/aah3860/node3.html).</P>
    </xs:documentation>
  </xs:annotation>
  <xs:restriction base="xs:string">
    <xs:enumeration value="ICRS"/>
    <xs:enumeration value="FK4"/>
    <xs:enumeration value="FK4-no-e"/>
    <xs:enumeration value="FK5"/>
    <xs:enumeration value="GAPPT"/>
    <xs:enumeration value="other"/>
  </xs:restriction>
</xs:simpleType>