be defined by/define a part of be measured from/be used by zero time measured from/be used by be measured from/be used by be defined normal to/define the orientation of be parallel to/define the orientation of be initiated with/initiate be terminated at/terminate be defined at/be used to define be defined using/intersect utilize/be referenced by be based upon/be used to define coordinate system earth point general coordinate system axis geodetic datum geoid geoid model local vertical datum measured depth system axis vertical datum offset vertical depth system axis vertical reference datum vertical time system axis coordinate system axis vertical datum