| Description:Image_Display_Geometry class provides an unambiguous description of the orientation of the image contents. This class assumes an image is displayed as described by a disp:Display_Direction class elsewhere in the label. In the unusual case where an image object does not have an associated disp:Display_Direction class, then, and only then, the optionalgeom:Display_Direction class in this class should be present. Coupled with the information in the associated Display_Direction class, any one of the Object_Orientation_* classes should allow unambiguous orientation of the contents of the image. The Local_Internal_Reference class is used to identify the object to which this instance of the Image_Display_Geometry class applies, and must be used if there is more than one instance of Image_Display_Geometry in the label. The appropriate value for local_reference_type is image_display_to_object. The Object_Orientation_North_East class is typically used for instruments for which the entire field of view is a portion of the target surface (e.g., instruments on Mars orbital spacecraft); otherwise use Object_Orientation_RA_Dec (e.g., flyby missions, missions with orbit radii much larger than the target radius such as Voyager or Cassini). At least one of these must be used. The two *_Identification classes used here are Central_Body (e.g., Saturn if you are using Planetocentric or planetographic coordinates in the Saturn system) and Target when the described object in the FoV is not the Central_Body. For example giving the orientation of the pole of Enceladus in Saturn Planetocentric coordinates, Central_Body = Saturn, Target = Enceladus. Bottom line: put in enough information so someone else can figure out the orientation of the field of view. We also offer an option to provide the pointing information as a quaternion. |
| Namespace Id: geom | Steward: geo | Role: TBD_role | Status: Active |
| Class Hierarchy: Image_Display_Geometry |
| No Attributes | |
| Association(s) | Name | Cardinality | Class |
| | Local_Internal_Reference | 0..1 | Local_Internal_Reference |
| | Display_Direction | 0..1 | Display_Direction |
| | Central_Body_Identification | 0..1 | Central_Body_Identification |
| | Geometry_Target_Identification | 0..1 | Geometry_Target_Identification |
| | Object_Orientation_North_East | 1..Unbounded | Object_Orientation_North_East |
| | Object_Orientation_RA_Dec | 1..Unbounded | Object_Orientation_RA_Dec |
| | Object_Orientation_Clock_Angles | 1..Unbounded | Object_Orientation_Clock_Angles |
| | Quaternion_Plus_To_From | 0..Unbounded | Quaternion_Plus_To_From |
| Referenced from: Geometry |