A reference object that describes the position, orientation and scale relationships of a reference ellipsoid to the Earth. Modern geodetic datums are defined with respect to the center of the Earth, while historical geodetic datums are defined with respect to fundamental points on the surface of the Earth.

identifier (M, K: ndt_long_name) (1144)

The code or full name of a geodetic datum. This should be the code of the geodetic datum, when available, or may be the full name of the geodetic datum when a code is not defined.


ellipsoid (M: ellipsoid(geodetic_datum))

This designated the ellipsoid that describes the surface of the geodetic datum. This ellipsoid is positioned with respect to the Earth to define the geodetic datum. Each geodetic_datum must be based upon one ellipsoid.


source (M, I: ref_source)

The provider of this instance of reference information. If this instance is provided by POSC, then this attribute must be "POSC". Each geodetic_datum must provided by one ref_source. Inherited from reference_behavior.


description (O: ndt_comment)

The definition of the geodetic datum.


status (O, I: ndt_instance_status) (0644)

The status of this instance in the version of Epicentre running in a data store. This is an enumerated datatype for which the following are the possible values: current, provisional, deprecated. Current - use without restriction. Provisional - use with caution, this value is for comment and may not appear in future releases of Epicentre. Deprecated - avoid use if possible, it is planned to remove this value in the next major release of Epicentre. Inherited from reference_behavior.


bounding_ring (O, I: SET[0:?] ring(face))

Defines the set of rings which form the boundary of the face. For example, a polygon can be bounded by one ring while a face with a hole in it can be bounded by two rings. Each geodetic_datum may be bounded by one or more ring. Inherited from face.


data_collection (I, V: SET[0:?] data_collection(collection_content))

Indicates the data collections that include this instance of E and P data. Each geodetic_datum may be a member of one or more data_collection. Inherited from e_and_p_data.


datum_for_axis (I, V: SET[0:?] vertical_depth_system_axis(measurement_datum))

The set of vertical depth system axes that use this vertical datum as their measurement datum. Each geodetic_datum may be used by one or more vertical_depth_system_axis. Inherited from vertical_datum.


datum_for_ranking (I, V: SET[0:?] object_ranking(base_object))

Indicates that an object is being used as a basis for comparison with another object. Each geodetic_datum may datum for ranking one or more object_ranking. Inherited from object_of_interest.


earth_model (I, V: SET[0:?] earth_model(spatial_object))

Indicates various earth models which include this spatial representation. Each geodetic_datum may be part of one or more earth_model. Inherited from spatial_object.


geocentric_coordinate_system (V: BAG[0:1] geocentric_coordinate_system(geodetic_datum))

This describes a geocentric coordinate system that is based upon this geodetic datum. Each geodetic_datum may be used to define one geocentric_coordinate_system.


geodetic_datum_alias (V: SET[0:?] geodetic_datum_alias(geodetic_datum))

Indicates the various identifiers by which this geodetic datum is known. Each geodetic_datum may be known as one or more geodetic_datum_alias.


geographic_coordinate_system (V: SET[0:?] geographic_coordinate_system(geodetic_datum))

This describes the geographic coordinate systems that are based upon this geodetic datum. Each geodetic_datum may be used to define one or more geographic_coordinate_system.


geoid_model (V: SET[0:?] geoid_model(geodetic_datum))

These are the geoid models that whose descriptions are based upon this geodetic datum. These geoid models describe one or more geoids using this geodetic datum as a reference. Each geodetic_datum may be referenced by one or more geoid_model.


graphical_element (I, V: SET[0:?] graphical_element(depicted_object))

Specifies one or more graphical elements which are depicting this data item. Each geodetic_datum may be depicted by one or more graphical_element. Inherited from e_and_p_data.


initiate_offset (I, V: SET[0:?] vertical_datum_offset(initial_datum))

The set of vertical datum offsets that define this datum as the initial datum. These offsets are described as being normal to this vertical datum. For an offset being defined as from A to B, this describes the datum as being used as A. Each geodetic_datum may initiate one or more vertical_datum_offset. Inherited from vertical_datum.


intersection_role (I, V: SET[0:?] space_time_operation(intersecting_object))

Indicates a space/time operation for which the object is involved as an intersecting agent. For projection, this is the screen on which an object is being projected. For proximity, this is the magnet object. Each geodetic_datum may be the intersecting object for one or more space_time_operation. Inherited from topological_object.


local_vertical_datum (I, V: SET[0:?] local_vertical_datum(vertical_datum))

The local vertical datums that are defined to be parallel to this vertical datum. Each geodetic_datum may define the orientation of one or more local_vertical_datum. Inherited from vertical_datum.


measured_depth_system_axis (I, V: SET[0:?] measured_depth_system_axis(vertical_datum))

These are the measured depth axes that use this vertical datum as the reference for vertical measurements, meaning measured depth is zero at this datum. Each geodetic_datum may be used by one or more measured_depth_system_axis. Inherited from vertical_datum.


object_of_ranking (I, V: SET[0:?] object_ranking(ranked_object))

Indicates that an object is being classified in a rank order based on its characteristics. Each geodetic_datum may object of ranking one or more object_ranking. Inherited from object_of_interest.


orient_axis (I, V: SET[0:?] vertical_depth_system_axis(normal_to_datum))

The set of vertical depth system axes that are defined to be oriented normal to this vertical datum. Each geodetic_datum may define the orientation of one or more vertical_depth_system_axis. Inherited from vertical_datum.


other_composite_spatial_object (I, V: SET[0:?] other_composite_spatial_object(composite_object))

Defines the set of composite spatial objects of which this spatial object is a component. Each geodetic_datum may be a component of one or more other_composite_spatial_object. Inherited from spatial_object.


primary_role (I, V: SET[0:?] space_time_operation(primary_object))

Indicates a space/time operation for which the object is involved as a primary agent. For degeneration, this object is being degenerated. For projection, this object is being projected onto another object. For proximity, this is the container object. Each geodetic_datum may be the primary object for one or more space_time_operation. Inherited from topological_object.


primary_topological_relationship (I, V: SET[0:?] topological_relationship(primary_topological_object))

Indicates a topological relationship in which the topologic object has the role of primary agent. For an object intersection type of "inside" this is the containing role (e.g., if a city is inside a county then the county would be the primary agent). For all other object intersection types the roles are symmetrical and both relationships must be searched for a particular object. For example, if a wellbore and a formation overlap then either could be chosen as the primary agent with the other chosen as the secondary agent. Each geodetic_datum may be primarily involved in one or more topological_relationship. Inherited from topological_object.


pty_area (I, V: SET[0:?] pty_area(face))

Each geodetic_datum may have a property of one or more pty_area. Inherited from face.


pty_geometry_2d_face (I, V: SET[0:?] pty_geometry_2d_face(face))

Each geodetic_datum may have a property of one or more pty_geometry_2d_face. Inherited from face.


pty_geometry_3d_face (I, V: SET[0:?] pty_geometry_3d_face(face))

Each geodetic_datum may have a property of one or more pty_geometry_3d_face. Inherited from face.


ref_naming_system (O: ref_naming_system)

The naming system in which the identifier is defined.


secondary_topological_relationship (I, V: SET[0:?] topological_relationship(secondary_topological_object))

Indicates a topological relationship in which the object is in the role of secondary agent. For an object intersection type of "inside" this is the contained role (e.g., if a well is inside a field then the well would be the secondary agent). For all other object intersection types the roles are symmetrical and both relationships must be searched for a particular object. For example, if a wellbore and a formation overlap then either could be chosen as the secondary agent with the other chosen as the primary agent. Each geodetic_datum may be involved in one or more topological_relationship. Inherited from topological_object.


shell (O, I: SET[0:?] shell(face))

Defines the shells of which this face is a component. Each geodetic_datum may be a component of one or more shell. Inherited from face.


source_reference (O, 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. Each geodetic_datum may documented by one ref_source_reference. Inherited from reference_behavior.


source_space_time_operation (I, V: BAG[0:1] space_time_operation(resulting_object))

Indicates the space/time operation from which a topological object was the result. For addition, this is the union of two objects. For degeneration, this is the degenerate object. Each geodetic_datum may be the result of one space_time_operation. Inherited from topological_object.


terminate_offset (I, V: SET[0:?] vertical_datum_offset(terminal_datum))

The set of vertical datum offsets that define this datum as a terminal datum. This means the an offset being expressed from A to B would refer to this vertical datum as B. Each geodetic_datum may terminate one or more vertical_datum_offset. Inherited from vertical_datum.


version (O, I: ref_epicentre_version) (0644)

Describes the version of Epicentre when this status was assigned to this instance of reference behavior Each geodetic_datum may version one ref_epicentre_version. Inherited from reference_behavior.


vertical_time_system_axis (I, V: SET[0:?] vertical_time_system_axis(vertical_datum))

The set of vertical time coordinate system axes that use this vertical datum as the location of origin of the time axis. Each geodetic_datum may be used by one or more vertical_time_system_axis. Inherited from vertical_datum.

Local rules:

Uniqueness Constraint
identifier
Supertype path(s):
e_and_p_data > object_of_interest > technical_object > geodetic_datum.
topological_object > spatial_object > simple_spatial_object > face > vertical_datum > geodetic_datum.
reference_behavior > geodetic_datum.

Entity projects as table GEODETIC_DATUM.

Referenced in Diagrams:

• CS1: Coordinate Systems
• CS2: Vertical Coordinate Axes
• HL4: Object Aliasing