Initial release. The Acceleration_Vector_Cartesian_Base is a three dimensional, rectangular coordinates vector. Uses units of linear acceleration. The included attributes are not sufficient to identify the endpoints of the vector. The Acceleration_Vector_Cartesian_Extended_Base is a three dimensional, rectangular coordinates vector. Uses units of linear acceleration. The included attributes are not sufficient to identify the endpoints of the vector. While the attribute Coordinate_System is optional, it must be used here if the coordinate system has not been specified in the enclosing class. Acceleration_Vector_Cartesian_Generic is a three dimensional, rectangular coordinates vector. Uses units of linear acceleration. Includes attributes to identify the endpoints of the vector. TBD The Axis_Vector describes the axis of the camera, defined as the normal to the image plane. A third model, CAHVORE, describes more general cameras including those with fisheye or otherwise wide field of view lenses. An additional vector, E, describes the apparent motion of the camera entrance pupil. (Taken from Camera Response Simulation for Planetary Exploration, by Dr. Richard Madison, Marc Pomerantz, and Dr. Abhinandan Jain, http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37771/1/05-1692 .pdf) The CAHVOR model describes a camera with radial lens distortion about the lens axis. In addition to the CAHV parameters, it includes 3-vectors O and R. Vector O is the optical axis of the lens, slightly different from vector A due to imperfect lens mounting. A ray from a point in space, passing through the pinhole, bends at the pinhole according to a function of the angle between the ray and optical axis O. The function is a polynomial whose coefficients are stored in vector R. (Taken from Camera Response Simulation for Planetary Exploration, by Dr. Richard Madison, Marc Pomerantz, and Dr. Abhinandan Jain, http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37771/1/05-1692 .pdf) The CAHV camera model is equivalent to the standard linear photogrammetric model for a pinhole camera, It is useful for very small field of view cameras and as a building block for more complex camera models. The CAHV model consists of four 3-vectors: C, A, H, and V. Vector C gives the location of the pinhole. Vector A gives the camera axis, defined as the normal to the image plane. Vector H encodes the horizontal axis of the image plane (H'), the coor- dinate (Hc) of the image column at the optical centre of the image plane, and the horizontal focal length (Hs) of the camera, in pixels. Vector V encodes corresponding information (V', Vc, Vs) in the vertical direction. The angle (theta) between horizontal and vertical vectors H' and V' is about 90 degrees. (Taken from Camera Response Simulation for Planetary Exploration, by Dr. Richard Madison, Marc Pomerantz, and Dr. Abhinandan Jain, http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37771/1/05-1692 .pdf) A camera model describes the mathematical relationship between the coordinates of a point in 3-dimensional space and its projection onto a 2-dimensional image plane. There are numerous types of camera models, only two of which are currently implemented. The Center_Vector describes the location of the pinhole of a camera. The Central_Body_Identification class uniquely identifies the body associated with the central body associated with an observation (for ex., a planet in the solar system). The Central_Body_To_Spacecraft_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the center of mass of the central body (e.g., planet) to the spacecraft. The Central_Body_To_Spacecraft_Position_Vector_Planetocentric is a spherical position vector in Planetocentric coordinates. It extends from the center of mass of the central body (e.g., planet) to the spacecraft. The Central_Body_To_Target_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the center of mass of the central body (e.g., planet) to the target specified in the parent Geometry_Orbiter class. The Central_Body_To_Target_Position_Vector_Planetocentric is a spherical position vector in Planetocentric coordinates. It extends from the center of mass of the central body (e.g., planet) to the target specified in the parent Geometry_Orbiter class. TBD. The Coordinate_Space_Identification class uniquely identifies a coordinate space (i.e., reference frame + position) with respect to which the values of the attributes in the containing class are defined. TBD The Coordinate_System class fully describes a coordinate system. It identifes the reference frame, coordinate system type (cartesian, planetocentric, etc.), origin, and the instantiation time of the system. The Coordinate_System_Origin_Identification class provides the origin of a coordinate system using body_spice_name (or _id). Includes stuff like inst/solar az/el, distances, etc. relative to a single specified reference frame or coordinate space TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD The distance between the two objects, both of which must be specified. The Distances class is a container class for distances. The Earth_To_Central_Body_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Earth to the central body (e.g., planet). The Earth_To_Spacecraft_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Earth to the spacecraft. The Earth_To_Target_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Earth to the target specified in the parent Geometry_Orbiter class. The Entrance_Vector describes the location of the entrance pupil of a camera. The Footprint_Vertices class provides a set of associations between pixels and their projections on the target. The pixels should be choose to be the vertices of a polygon, plotted sequenually in a the direction. The Generic_Vectors class is a container class for all of the build your own vector templates. The Geometry class is a container for all geometric information in the label. The Geometry_Identification_Base class provides multiple attributes which can be used to identify a physical object (spacecraft, planet instrument, transmitter, system barycenter, etc.) or a reference frame. At least one must be used. The Geometry_Lander class is a container for all geometric information in the label relating to a landed spacecraft, including rovers. The Geometry_Orbiter class is a container for geometric information (positions, velocities, orientations, etc.) relevant to orbiter or flyby spacecraft observations. The Horizontal_Vector encodes the horizontal axis of the image plane (H'), the coordinate (Hc) of the image column at the optical centre of the image plane, and the horizontal focal length (Hs) of the camera, in pixels. The Illumination_FOV_Range_Values class contains attributes providing illumination parameters as minimum/maximum pairs for either the field of view or the portion in the FoV of the target specified in the parent Geometry_Orbiter class. The Illumination_Geometry class contains two optional classes used to describing the field of view lighting. The Illumination_Single_Values class contains attributes providing illumination parameters at a single location in the field of view. If reference_location is used, and indicates a point on a target, the target must be the one specified in the parent Geometry_Orbiter class. Image_Display_Geometry class provides an unambiguous description of the orientation of the image contents. Given an image, displayed as described by the Display_Direction class, any one of the Object_Orientation_* classes should allow unambiguous orientation of the contents of the image. The use of disp:Display_Direction is optional, but must be given either here or in the Display Discipline Area of the label. 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. Used when the list values are angles. The List_Index class is a private (i.e., abstract) class designed to enable the use of indexed lists. The minimum requirement is at least one of sequence number, name or "id", plus the set of values themselves. Used when the list values are lengths. Used when the list values have no units. Used when the list values are temperatures. Used when the list values are strings. The Motion_Counter class provides a set of integers which describe a (potentially) unique location (position / orientation) for a rover or other movable object. Each time an event occurs that results in a movement, a new motion counter value is created. This includes intentional motion due to drive commands, as well as potential motion due to other articulating devices, such as arms or antennae. This motion counter (or part of it) is used as a reference to define instances of coordinate systems which can move such as SITE or ROVER frames. The motion counter is defined in a mission-specific manner. Although the original intent was to have incrementing indices (e.g., MER), the motion counter could also contain any integer values which conform to the above definition, such as time or spacecraft clock values. The Motion_Counter_Index class identifies and populates one element of a Motion_Counter list. The class should be repeated for each element of the list. The Object_Orientation_Clock_Angles class provides the clock angles measure from the center of the field of view to celestial and ecliptic north, and to the sun. The Object_Orientation_North_East class provides the parameters needed to describe the orientation of an external coordinate system relative to the image coordinate frame as described by the Image_Orientation class. The Object_Orientation_RA_Dec class provides the parameters needed to describe the orientation of the celestial reference frame relative to the image coordinate frame as described by the Image_Orientation class. Within the Geometry dictionary context, an "Observer" is the body on the "from" end of a vector, quaternion, or other translation through space. The Optical_Terms provides the optical axis coefficients used for lens-distortion correction when the distortion is radial. TBD The Pixel_Dimensions class contains information regarding pixel size. The Pixel_Intercept class provides the latitude and longitude on the surface of the target for the projection of the specificed pixel. The pixel is specfied using either reference_pixel_location or Reference_Pixel. Although each of these is optional, one must be used. The Pixel_Size_Projected class gives the size, in units of length (e.g., kilometers) of the projection of a pixel onto the surface of the target which is specified in the parent Geometry_Orbiter class. The reference_location attribute is used to identify the specific point on the target. The Polynomial_Coefficients_1 class provides a one polynomial coefficient. The Polynomial_Coefficients_2 class provides two polynomial coefficients. The Polynomial_Coefficients_3 class provides three polynomial coefficients. The Position_Vector_Cartesian_Base is a three dimensional, rectangular coordinates vector. Uses units of length. The included attributes are not sufficient to identify the endpoints of the vector. The Position_Vector_Cartesian_Extended_Base is a three dimensional, rectangular coordinates vector. Uses units of length. The included attributes are not sufficient to identify the endpoints of the vector. While the attribute Coordinate_System is optional, it must be used here if the coordinate system has not been specified in the enclosing class. Position_Vector_Cartesian_Generic is a three dimensional, rectangular coordinates vector. Uses units of length. Includes attributes to identify the endpoints of the vector. The Position_Vector_Planetocentric_Base is a three dimensional spherical vector (radius, longitude, latitude) with the angular coordinates defined to be consistent with the Planetocentric coordinate system. Uses linear units for the radius dimension, and angular units for the other two dimensions. The included attributes are not sufficient to identify the endpoints of the vector. The Position_Vector_Planetocentric_Extended_Base is a three dimensional spherical vector (radius, longitude, latitude) with the angular coordinates defined to be consistent with the Planetocentric coordinate system. Uses linear units for the radius dimension, and angular units for the other two dimensions. The included attributes are not sufficient to identify the endpoints of the vector. While the attribute Coordinate_System is optional, it must be used here if the coordinate system has not been specified in the enclosing class. The Position_Vector_Planetocentric_Generic is a three dimensional spherical vector (radius, longitude, latitude) with the angular coordinates defined to be consistent with the Planetocentric coordinate system. Uses linear units for the radius dimension, and angular units for the other two dimensions. Includes attributes to identify the endpoints of the vector. TBD The Quaternion_SPICE_Style class provides a quaternion that describes the transformation information between two reference frames. For a SPICE style quaternion the order of the four components is (Qcos, Qsin1, Qsin2, Qsin3). See NAIF SPICE documentation for additional details. The Quaternion__non_SPICE_Style class provides a quaternion that describes the transformation information between two reference frames. For a non-SPICE style quaternion the order of the four components is (Qsin1, Qsin2, Qsin3, Qcos). See NAIF SPICE documentation for additional details. The Radial_Vector provides the radial lens distortion coefficients defined in the ground (object) coordinate system. TBD The Reference_Frame_Identification class is a base class for identifying reference frames. These are frames in the NAIF sense, i.e., three orthogonal axes with a specified orientation, but without a fixed origin. The Reference_Pixel class provides the pixel coordinates, line and sample, to which values in the containing class apply. Integer values indicate the center of the pixel. Sub-pixel values are permitted. For pixel_sample, the leading edge (left edge for sample increasing to the right) has a value 0.5 less than the integer value at the center, and the value for the trailing edge is the center integer value + 0.5. For pixel_line, the leading and trailing edges (top and bottom respectively for line increasing downward) again are -0.5 and +0.5 with respect to the center integer value. TBD The SPICE_Kernel_Files class provides references to the SPICE files used when calculating geometric values. The preferred reference mechanism is to give the LIDVID for each SPICE file. If a LIDVID has not been asigned, then the file name of that file is used. The SPICE_Kernel_Identification class includes the SPICE kernel type and provides three alternatives for identifying the product: LIDVID using Internal_Reference (this is the preferred option), the official file name of the kernel file as assigned by the PDS NAIF node, or the local file name assigned by the mission pending the official NAIF designation. Local file names must be unique, and one-to-one associations between the local file name and the NAIF file name or LIDVID must be maintained. The SSB_To_Central_Body_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Solar System Barycenter to the central body (e.g., planet). The SSB_To_Spacecraft_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Solar System Barycenter to the spacecraft. The SSB_To_Target_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Solar System Barycenter to the target specified in the parent Geometry_Orbiter class. The Spacecraft_Relative_To_Central_Body_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the spacecraft with respect to the central body (e.g., planet). The Spacecraft_Relative_To_Earth_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the spacecraft with respect to Earth. The Spacecraft_Relative_To_SSB_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the spacecraft with respect to the Solar System Barycenter. Spacecraft_Relative_To_Sun_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the spacecraft with respect to the center of the Sun. The Spacecraft_Relative_To_Target_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the spacecraft with respect to the target specified in the parent Geometry_Orbiter class. The Spacecraft_Relative_To_Target_Velocity_Vector_Planetocentric is a spherical velocity vector in Planetocentric coordinates that gives the velocity of the spacecraft with respect to the designated target. The Spacecraft_To_Target_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the spacecraft to the target specified in the parent Geometry_Orbiter class. The Spacecraft_To_Target_Position_Vector_Planetocentric is a spherical position vector in Planetocentric coordinates. It extends from the spacecraft to the target specified in the parent Geometry_Orbiter class.. The Specific_Cartesian_Vectors class is a container class for all cartesian vectors with pre-identified endpoints. The Specific_Planetocentric_Vectors class is a container class for all planetocentric vectors with pre-identified endpoints. The Specific_Position_Vectors class is a container class for all position vectors with pre-identified endpoints. The Specific_Velocity_Vectors class is a container class for all velocity vectors with pre-identified endpoints. The Sun_To_Central_Body_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Sun to the central body (e.g., planet). The Sun_To_Spacecraft_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Sun to the spacecraft. The Sun_To_Target_Position_Vector_Cartesian is a linear, rectangular coordinates vector from the Sun to the target specified in the parent Geometry_Orbiter class. The Surface_Geometry class contains classes and attributes for various points of the surface of the target designated in the enclosing Geometry_Orbiter. Within the Geometry dictionary context, a "Target" is the body on the "to" end of a vector, quaternion, or other translation through space. The Target_Relative_To_Central_Body_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the designated target with respect to the central body (e.g., planet). The Target_Relative_To_Central_Body_Velocity_Vector_Planetocentric is a spherical velocity vector in Planetocentric coordinates that gives the velocity of the target with respect to the central body. The Target_Relative_To_Earth_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the designated target with respect to Earth. The Target_Relative_To_SSB_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the designated target with respect to the Solar System Barycenter. The Target_Relative_To_Spacecraft_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the designated target with respect to the spacecraft. The Target_Relative_To_Spacecraft_Velocity_Vector_Planetocentric is a spherical velocity vector in Planetocentric coordinates that gives the velocity of the target with respect to the spacecraft. Target_Relative_To_Sun_Velocity_Vector_Cartesian is a velocity vector in rectangular coordinates that gives the velocity of the designated target with respect to the center of the sun. This is a generic vector in Cartesian space. The "x", "y", and "z" component have no units. This a Cartesian pixel vector generally used in camera models. This is a generic unit vector in Cartesian space. The "x", "y", and "z" component have no units and are restricted to values between -1.0 and 1.0 inclusive. Further the length of the vector square root of the (sum of the squares of the components) must be 1.0. The Velocity_Vector_Cartesian_Base is a three dimensional, rectangular coordinates vector. Uses units of linear velocity. The included attributes are not sufficient to identify the endpoints of the vector. The Velocity_Vector_Cartesian_Extended_Base is a three dimensional, rectangular coordinates vector. Uses units of linear velocity. The included attributes are not sufficient to identify the endpoints of the vector. While the attribute Coordinate_System is optional, it must be used here if the coordinate system has not been specified in the enclosing class. Velocity_Vector_Cartesian_Generic is a three dimensional, rectangular coordinates vector. Uses units of linear velocity. Includes attributes to identify the endpoints of the vector. The Velocity_Vector_Planetocentric_Base is a three dimensional spherical vector (radius, longitude, latitude) with the angular coordinates defined to be consistent with the Planetocentric coordinate system. Uses linear velocity units for the radius dimension, and angular velocity units for the other two dimensions. The included attributes are not sufficient to identify the endpoints of the vector. While the attribute Coordinate_System is optional, if it is appropriate for this vector, it must be used here if the coordinate system has not been specified in the Geometry_Orbiter class. The Velocity_Vector_Planetocentric_Extended_Base is a three dimensional spherical vector (radius, longitude, latitude) with the angular coordinates defined to be consistent with the Planetocentric coordinate system. Uses linear velocity units for the radius dimension, and angular velocity units for the other two dimensions. The included attributes are not sufficient to identify the endpoints of the vector. While the attribute Coordinate_System is optional, it must be used here if the coordinate system has not been specified in the enclosing class. The Velocity_Vector_Planetocentric_Generic is a three dimensional spherical vector (radius, longitude, latitude) with the angular coordinates defined to be consistent with the Planetocentric coordinate system. Uses linear velocity units for the radius dimension, and angular velocity units for the other two dimensions. Includes attributes to identify the endpoints of the vector. The Vertical_Vector encodes the vertical axis of the image plane (V' or Vp), the coordinate (Vc) of the image row(?) at the optical centre of the image plane, and the vertical focal length (Vs) of the camera, in pixels. This section contains the simpleTypes that provide more constraints than those at the base data type level. The simpleTypes defined here build on the base data types. This is another component of the common dictionary and therefore falls within the pds namespace. The body_positive_pole_clock_angle element specifies the direction of a body's rotation axis in an image. This attribute typically is used when specifying body center coorinates for dwarf planets, minor planets, their satellites, and for comets. It is measured from the 'upward' direction in the image, clockwise to the direction of the positive rotational pole as projected into the image plane, assuming the image is displayed as defined by the Display_Direction class. The positive pole is used to define the poles of dwarf planets, minor planets, their satellites, and comets according to the right-hand rule. "positive" is the pole toward which the thumb points when the fingers are curled in the body's direction of rotation. The body_spice_id attribute is a NAIF-recognized numeric identifier for a physical object (spacecraft, planet, instrument transmitter, system barycenter, etc., associated with the data. The body_spice_name attribute is a NAIF-recognized string identifier for a physical object (spacecraft, planet, instrument transmitter, system barycenter, etc., associated with the data. The first coefficient of a polynomial. The second coefficient of a polynomial. The third coefficient of a polynomial. The calibration_source_id is used to identify the source used in calibrating the instrument. The celestial_north_clock_angle attribute specifies the direction of celestial north at the center of an image. It is measured from the 'upward' direction, clockwise to the direction toward celestial north, assuming the image is displayed as defined by the Display_Direction class.. The central_body_north_pole_clock_angle element specifies the direction of the central body's (e.g., planet's)rotation axis in an image. It is measured from the 'upward' direction in the image, clockwise to the direction of the northern rotational pole as projected into the image plane, assuming the image is displayed as defined by the Display_Direction class. The north pole of a planet or any of its satellites in the solar system is the pole of the rotation axis that is in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North pole. The coordinate_system_time provides the instantiation time for the coordinate system. The declination_angle (Dec) attribute provides the value of an angle on the celestial sphere, measured north from the celestial equator to the point in question. (For points south of the celestial equator, negative values are used.) declination is used in conjunction with the right_ascension attribute to specify a point on the sky. TBD. TBD. TBD. The distance attribute provides the scaler distance between to objects or points. Assuming the image is displayed as defined by the Display_Direction class, the east_azimuth attribute provides the value of the angle between a line from the image center to the east and a reference line in the image plane. The reference line is a horizontal line from the image center to the middle right edge of the image. This angle increases in a clockwise direction. The ecliptic_north_clock_angle attribute specifies the direction of ecliptic north at the center of an image. It is measured from the 'upward' direction, clockwise to the direction toward ecliptic north, assuming the image is displayed as defined by the Display_Direction class.. The emission_angle element provides the value of the angle between the surface normal vector at the intercept point and a vector from the intercept point to the spacecraft. The emission_angle varies from 0 degrees when the spacecraft is viewing the subspacecraft point (nadir viewing) to 90 degrees when the intercept is tangent to the surface of the target body. Thus, higher values of emission_angle indicate more oblique viewing of the target. Values in the range of 90 to 180 degrees are possible for ring data. The frame_spice_id attribute is a NAIF-recognized numeric identifier for a reference frame associated with the data. The frame_spice_name attribute is a NAIF-recognized string identifier for a reference frame associated with the data. geometry_reference_time is the time at which each of the values in the containing class is correct. horizontal_coordinate_pixel (sample) is the horizontal coordinate of a specific pixel. The horizontal_pixel_scale_factor provides a scaling factor which when multiplied by the distance to a point of the surface of the target identified in the parent Geometry_Orbiter class gives the horizontal size of a pixel projected on the target in units of length (e.g., kilometers). The horizontal_pixel_size_angular provides the angular measure of the horizontal field of view of a single pixel. This is equivalent to the PDS3 element horizontal_pixel_field_of_view. The horizontal_pixel_size_projected provides the the size of the horizontal field of view of a single pixel projected onto the target specified in the parent Geometry_Orbiter class. Analogus to PDS3 keyword PIXEL_SCALE The illumination_range_designation indicates whether values given in the Illumination_Range_Values class apply to the entire field of view, or the portion within the field of view of the target specified in the parent Geometry_Orbiter class. The incidence_angle element provides a measure of the lighting condition at the intercept point. Incidence angle is the angle between the local vertical at the intercept point (surface) and a vector from the intercept point to the sun. The incidence_angle varies from 0 degrees when the intercept point coincides with the subsolar point to 90 degrees when the intercept point is at the terminator (i.e., in the shadowed or dark portion of the target body). Thus, higher values of incidence_angle indicate the existence of a greater number of surface shadows. Note: In PDS labels for Magellan's altimetry and radiometry products, and for Lunar Reconnaissance Orbiter Mini-RF products, incidence_angle is defined as the value of the angle between the local vertical and the spacecraft direction. For Magellan this is measured at the center of the radiometer footprint at rad_spacecraft_epoch_time. TBD. TBD. TBD. TBD. TBD. TBD. TBD. TBD. The latitude component of a Planetocentric position vector. Planetocentric latitude is the angle between the equator plane and a vector connecting the point of interest and the origin of the coordinate system. Latitudes are defined to be positive in the northern (as defined by the IAU) hemisphere. The latitude component of a Planetocentric velocity vector. Planetocentric latitude is the angle between the equator plane and a vector connecting the point of interest and the origin of the coordinate system. Latitudes are defined to be positive in the northern (as defined by the IAU) hemisphere. The local_spice_kernel_name attribute is the mission designated file name for a SPICE kernel. The longitudinal component of a Planetocentric position vector. Planetocentric longitude is measured from the IAU approved prime meridian for the body and increases toward the east. The longitudinal component of a Planetocentric velocity vector. Planetocentric longitude is measured from the IAU approved prime meridian for the body and increases toward the east. The maximum_emission_angle element provides the largest value for the emission angle in the observation. The maximum_incidence_angle element provides the largest value for the incidence angle in the observation. The maximum_phase_angle element provides the largest value for the phase angle in the observation. The minimum_emission_angle element provides the smallest value for the emission angle in the observation. The minimum_incidence_angle element provides the smallest value for the incidence angle in the observation. The minimum_phase_angle element provides the smallest value for the phase angle in the observation. TBD. TBD. Assuming the image is displayed as defined by the Display_Direction class, the north_azimuth attribute provides the value of the angle between a line from the image center to the north pole and a reference line in the image plane. The reference line is a horizontal line from the image center to the middle right edge of the image. This angle increases in a clockwise direction. The phase_angle element provides a measure of the relationship between the instrument viewing position and incident illumination (such as solar light). Phase_angle is measured at the target; it is the angle between a vector to the illumination source and a vector to the instrument. If not specfied, the target is assumed to be at the center of the instrument field of view. If illumination is from behind the instrument, phase_angle will be small. The pixel_latitude attribute gives the value of the planetocentric latitude on the target of the projection of a specified pixel. The pixel_longitude attribute gives the value of the planetocentric longitude on the target of the projection of a specified pixel. One of the four components of a quaternion (Qcos, Qsin1, Qsin2, Qsin3). The order used in a quaternion depends on the 'style' of the quaternion. One of the four components of a quaternion (Qcos, Qsin1, Qsin2, Qsin3). The order used in a quaternion depends on the 'style' of the quaternion. One of the four components of a quaternion (Qcos, Qsin1, Qsin2, Qsin3). The order used in a quaternion depends on the 'style' of the quaternion. One of the four components of a quaternion (Qcos, Qsin1, Qsin2, Qsin3). The order used in a quaternion depends on the 'style' of the quaternion. The radial component of a spherical or cylindrical velocity vector. The radial component of a spherical or cylindrical position vector (e.g., the radius coordinate in Planetocentric coordinates). The reference_location indicates the position to which values in the containing class apply. If the reference location is on a target, the target is the one specified in the parent Geometry_Orbiter class. The reference_pixel_location indicates the position of the pixel to which values in the containing class apply. The right_ascension_angle attribute provides the value of right ascension (RA) as an angle. Right ascension is measured from the vernal equinox or the first point of Aries, which is the place on the celestial sphere where the Sun crosses the celestial equator from south to north at the March equinox. Right ascension is measured continuously in a full circle from that equinox towards the east. Right ascension is used in conjunction with the declination attribute to specify a point on the sky.Note Right Ascension is normally given in hour angles in which case the appropriate attribute is right_ascension_hour_angle. The right_ascension_hour_angle attribute provides the value of right ascension (RA) as in terms of hour angles (hh:mm:ss.sss...). Right ascension is measured from the vernal equinox or the first point of Aries, which is the place on the celestial sphere where the Sun crosses the celestial equator from south to north at the March equinox. Right ascension is measured continuously in a full circle from that equinox towards the east. Right ascension is used in conjunction with the declination attribute to specify a point on the sky. The solar_elongation element gives the angle between the line of sight of observation and the direction of the Sun. Note: For IRAS: The line of sight of observation is the boresight of the telescope as measured by the satellite sun sensor. TBD. The spacecraft_geocentric_distance attribute provides the scaler distance between the spacecraft and the center of Earth. The spacecraft_heliocentric_distance attribute provides the scaler distance between the spacecraft and the center of the Sun. The spacecraft_to_central_body_distance attribute provides the scaler distance between the spacecraft and the center of the central body (e.g., the center of Mars when opperating in the Mars system). The spacecraft_to_target_boresight_intercept_distance attribute provides the scaler distance between the spacecraft and the boresight vector intercept point on the surface of the target specified in the parent Geometry_Orbiter class. The spacecraft_to_target_center_distance attribute provides the scaler distance between the spacecraft and the center of the target specified in the parent Geometry_Orbiter class. The spacecraft_to_target_subspacecraft_distance attribute provides the scaler distance between the spacecraft and the subspacecraft point on the surface of the target specified in the parent Geometry_Orbiter class. The subsolar_azimuth attribute provides the value of the angle between the line from the center of an image to the subsolar point on the target and a horizontal reference line (in the image plane) extending from the image center to the middle right edge of the image. The values of this angle increase in a clockwise direction. The subsolar_latitude attribute gives the value of the planetocentric latitude at the subsolar point on the target. The subsolar_longitude attribute gives the value of the planetocentric longitude at the subsolar point on the target. The subspacecraft_azimuth attribute provides the value of the angle between the line from the center of an image to the subspacecraft point on the target and a horizontal reference line (in the image plane) extending from the image center to the middle right edge of the image. The values of this angle increase in a clockwise direction. The subspacecraft_latitude attribute gives the value of the planetocentric latitude at the subspacecraft point on the target. The subspacecraft_longitude attribute gives the value of the planetocentric longitude at the subspacecraft point on the target. The sun_direction_clock_angle attribute specifies the direction of the sun as an angle measured from a line 'upward' from the center of the field of view, clockwise to the direction toward sun, assuming the image is displayed as defined by the Display_Direction class.. The target_geocentric_distance attribute provides the scaler distance between the center of the target and the center of the Earth. The target_heliocentric_distance attribute provides the scaler distance between the center of the target and the center of the Sun. The target_north_pole_clock_angle element specifies the direction of the target body's rotation axis in an image. It is measured from the 'upward' direction in the image, clockwise to the direction of the northern rotational pole as projected into the image plane, assuming the image is displayed as defined by the Display_Direction class. The north pole of a planet or any of its satellites in the solar system is the pole of the rotation axis that is in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North pole. The target_positive_pole_clock_angle element specifies the direction of the target body's rotation axis in an image. It is measured from the 'upward' direction in the image, clockwise to the direction of the positive rotational pole as projected into the image plane, assuming the image is displayed as defined by the Display_Direction class. The positive pole is used to define the poles of dwarf planets, minor planets, their satellites, and comets according to the right-hand rule. "positive" is the pole toward which the thumb points when the fingers are curled in the body's direction of rotation. The target_ssb_distance attribute provides the scaler distance between the center of the target and the Solar System Barycenter. vertical_coordinate_pixel (line) is the vertical coordinate of a specific pixel. The vertical_pixel_scale_factor provides a scaling factor which when multiplied by the distance to a point of the surface of the target identified in the parent Geometry_Orbiter class gives the vertical sizes of a pixel projected on the target in units of length (e.g., kilometers). The vertical_pixel_size_angular provides the angular measure of the vertical field of view of a single pixel. This is equivalent to the PDS3 element vertical_pixel_field_of_view. The vertical_pixel_size_projected provides the size of the vertical field of view of a single pixel projected onto the target specified in the parent Geometry_Orbiter class. Analogus to PDS3 keyword PIXEL_SCALE The x component of a Cartisean acceleration vector. The x component of a Cartisean vector which has no units. The x component of a Cartisean pixel vector; typically used in cameral models. The x component of a Cartisean position vector. The x component of a unit Cartisean vector. The x component of a Cartisean velocity vector. The y component of a Cartisean acceleration vector. The y component of a Cartisean vector which has no units. The y component of a Cartisean pixel vector; typically used in cameral models. The y component of a Cartisean position vector. The y component of a unit Cartisean vector. The y component of a Cartisean velocity vector. The z component of a Cartisean acceleration vector. The z component of a Cartisean vector which has no units. The z component of a Cartisean pixel vector; typically used in cameral models. The z component of a Cartisean position vector. The z component of a unit Cartisean vector. The z component of a Cartisean velocity vector.