Entity vertical_datum_offset

• The offset between two vertical datums in the direction normal to the initial vertical datum. These offsets provide a vertical link to the Earth when at least one related offset is based upon a vertical datum tied to the Earth. The offset may be defined through a selected point, when appropriate.

Attribute                                 Flags   Data Type

From reference_behavior:
   source_reference                       I       ref_source_reference

                                          The reference used by source to provide the standard
                                          instance, such as Petroleum Industry Data Dictionary
                                          (PIDD), Websters Ninth New Collegiate Dictionary,
                                          etc. 

   source                                 MI      ref_source

                                          The provider of this instance of reference information.
                                          If this instance is provided by POSC, then this
                                          attribute must be "POSC". 


From transient_association:
   data_collection                        IV      set[0 .. N] of (data_collection)

                                          Indicates the data collections that include this
                                          instance of E and P data. 

   graphical_element                      IV      set[0 .. N] of (graphical_element)

                                          Specifies one or more graphical elements which
                                          are depicting this data item. 

   description                            I       ndt_comment

                                          A description of the transient association. 

   duration                               IN      ndt_time

                                          Defines the duration of the association expressed
                                          in any valid units of time. 

   end_time                               IN      ndt_date_tod

                                          End time of the association. 

   start_time                             IN      ndt_date_tod

                                          Start time of the association. 

   caused_by                              I       activity

                                          Specifies the activity which establishes this
                                          association. 

   terminated_by                          I       activity

                                          Specifies the activity which established the
                                          termination of a transient association between
                                          two objects. 


length_offset                             N       ndt_length_midrange

                                          Length of the offset from the initial vertical
                                          datum to the terminal vertical datum. This length
                                          is measured in the vertical direction, positive
                                          upwards. 

time_offset                               N       ndt_seismic_time

                                          One way travel time of the offset from the initial
                                          vertical datum to the terminal vertical datum.
                                          This travel time is measured in the vertical direction,
                                          positive upwards. 

earth_point                               U       earth_point

                                          This is an earth point that is defined as being
                                          on the line normal to the initiating datum in
                                          which the offset is described. This allows non-parallel
                                          datums to be described with offsets at various
                                          points. 

initial_datum                             MU      vertical_datum

                                          The vertical datum which is the initiation of
                                          an offset between two vertical datums. The offset
                                          is described normal to this datum. For an offset
                                          from A to B, this points to A. 

terminal_datum                            MU      vertical_datum

                                          The vertical datum which is the termination of
                                          the offset between two vertical datums. When the
                                          offset is expressed from A to B, this defines
                                          B. 

End of entity vertical_datum_offset

M - mandatory, U - unique, I - inherited, V - inverse, N - named type