orientation

<xsd:attribute name="orientation" default="horizontal">
  <xsd:annotation>
    <xsd:documentation>
      <p>The orientation attribute is used to express how to draw asymmetric glyphs. In PD, the orientation of Process Nodes is either horizontal or vertical. It refers to an (imaginary) line connecting the two in/out sides of the PN. In PD, the orientation of Tags and Terminals can be left, right, up or down. It refers to the direction the arrow side of the glyph is pointing at.</p>
    </xsd:documentation>
  </xsd:annotation>
  <xsd:simpleType>
    <xsd:restriction base="xsd:string">
      <!-- horizontal / vertical are for process nodes -->
      <xsd:enumeration value="horizontal"/>
      <xsd:enumeration value="vertical"/>
      <!-- left / right / up / down are for tags and terminals -->
      <xsd:enumeration value="left"/>
      <xsd:enumeration value="right"/>
      <xsd:enumeration value="up"/>
      <xsd:enumeration value="down"/>
    </xsd:restriction>
  </xsd:simpleType>
</xsd:attribute>