Filling Out the Geometry Dictionary Classes

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Revision as of 16:04, 29 June 2016 by Raugh (talk | contribs) (added link to quick intro)
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The geometry dictionary is a discipline dictionary, which means that its classes will appear in the <Discipline_Area> at the bottom of the <Observation_Area> in observational product labels (and in the <Context_Area>, if appropriate, in non-observational products). The classes in this dictionary define the observational geometry relevant to the data objects presented in the product.

If this is your first experience using the Geometry Dictionary, you might find this overview helpful:

Update: 27 June 2016, for Geometry dictionary version 1.3.0.0.

<Geometry>

REQUIRED

This is the wrapper class that for the Geometry Dictionary. It must be used whenever you want or need to include geometry information in a label. Any mission using NAIF software to calculate geometry should include the <SPICE_Kernel_Files> class; you'll likely need to include the <Image_Display_Geometry> class for anything image-like; and one of either <Geometry_Orbiter> or <Geometry_Lander> is required.

Note: As of this writing, spacecraft-oriented flyby and orbiter geometry classes are provided in this dictionary, as well as some classes that support ground-based geometry values. If you have other types of geometry to document in your labels, or don't find what you expect, please do notify your PDS node consultant and ask for the preferred method of recording this information.

These classes are necessarily fairly complex, so the descriptions have been broken into separate pages corresponding to the major subclasses. You may, if you need to, have more than one <Geometry> class in your label.

<SPICE_Kernel_Files>

OPTIONAL

This class is used to cite the SPICE kernel files used in calculating the associated geometric values (for missions using the NAIF SPICE Toolkit). Your PDS node will likely require you to use this class if the NAIF software was used. It may appear only once in each <Geometry> class.

<Image_Display_Geometry>

OPTIONAL

This class is used to provide orientation to fundamental directions (North, East, etc.) with respect to a declared display orientation. If your data object is an image or image-like thing (a 2D spectrum, say), you will be required to include this class in your geometry info. You may repeat this class if you have more than one image-like thing to describe in your label.

<Geometry_Lander>

OPTIONAL

This class provides geometric information relevant to a landed spacecraft, including rovers. One of either this class or Geometry_Orbiter is required; you may have both. You may also repeat this class if appropriate.

This class does not yet appear to be ready for use. If you have lander geometry to describe, including instrument articulation angles and motion tracking information, please contact your PDS node consultant for assistance.

  • Filling out the Geometry_Lander Class - still in development

<Geometry_Orbiter>

OPTIONAL

This class provides detailed geometry (positions, orientations, velocities, and so on) appropriate for orbiting and fly-by spacecraft. One of this class or Geometry_Lander is required; you may have both. You may also repeat this class if appropriate.