<complexType name="PlungeMeasureType">
  <annotation>
    <documentation>A measure type for plunge angles of linear geological features. Plunge is the vertical angle between a line and the horizontal plane, measured downward from horizontal. The angle is positive for features dipping below horizontal and negative for features pointing upward above horizontal. Values are constrained to the range -90° to +90° (or equivalent in other angular units), where 0° represents horizontal, +90° represents vertically downward, and -90° represents vertically upward. Plunge is used extensively in structural geology to describe the orientation of fold axes, lineations, drill holes, mineral elongations, and other linear features. When combined with trend (the horizontal direction), plunge provides complete three-dimensional orientation of a line in space.</documentation>
  </annotation>
  <simpleContent>
    <restriction base="diggs:PlaneAngleMeasureType">
      <minInclusive value="-90">
        <annotation>
          <documentation>Minimum plunge value (-90 degrees or equivalent): vertically upward orientation</documentation>
        </annotation>
      </minInclusive>
      <maxInclusive value="90">
        <annotation>
          <documentation>Maximum plunge value (+90 degrees or equivalent): vertically downward orientation</documentation>
        </annotation>
      </maxInclusive>
    </restriction>
  </simpleContent>
</complexType>