<simpleType name="LinearReferencingMethodTypeEnum">
  <restriction base="string">
    <enumeration value="absolute">
      <annotation>
        <documentation>Position is the distance from a fixed origin, typically the first coordinate of the linear extent, for example measured depth from the kelly bushing, distance along a geophysical trackline from its start, or distance from the top of a core sample.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="relative">
      <annotation>
        <documentation>Position is the distance from a referent point along the linear element, for example depth below ground surface, distance from a line intersection point, or distance from a kickoff point in directional drilling.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="interpolative">
      <annotation>
        <documentation>Position is found by interpolating between known control points (anchor points) along the linear element, for example core positions adjusted for stretch or compression between the top and bottom of the core, trackline positions interpolated between GPS waypoints, or borehole positions adjusted with downhole survey stations.</documentation>
      </annotation>
    </enumeration>
  </restriction>
</simpleType>