1. PDS4 Geometry Model Project
Edward Guinness
PDS Geosciences Node
Washington University, St. Louis
July 17, 2013

2. PDS4 Geometry Model Project
Define a set of functional requirements for PDS4 geometry information from a science user's perspective.
Address geometry needs to support both data discovery (search) and science analysis.
Initial focus limited to geometry related to observations of solid bodies.
Result is to be a "white paper" detailing the requirements.
Draft to be completed in August 2013.

3. Approach
Ed Guinness from the PDS Geosciences Node is leading the task.
He has requested input and ideas from scientists and PDS data users from both inside and outside the PDS:
Geosciences Node Advisory Group
Geosciences and Imaging Node members
ESA Planetary Science Archive members
Mars Express Data Archive Working Group members.
So far about six people have provided responses.

4. Results from User Survey - General
Most users focused on geometry data associated with imaging data sets.
Most users suggested that the geometry data should be in the PDS labels.
Several suggested the usefulness of geometry backplanes (e.g., like MRO CRISM and MEX OMEGA geometry backplanes) for science analysis.
Backplanes provide geometry values for every pixel in an image or map.

5. Results from User Survey – Orbital Data
Types of geometry data suggested for orbital data sets:
Spacecraft/instrument location at time of observation,
Observation location on surface of the body,
Center point and footprint
Lighting and viewing angles (incidence, emission, phase),
Distance from Sun,
Description of how geometry data from derived,
Definition of coordinate/reference system used for geometry data.
A mechanism is needed for providing updates to the geometry data.

6. Results from User Survey – Lander/Rover Data
Types of geometry data suggested for landers and rovers:
Lighting and viewing angles,
Distance from Sun,
Spacecraft location for rovers,
Camera models.

7. Issues and Remaining Work
Small sample size of users.
Any additional inputs from interested IPDA members are welcome.
Need to provide geometry requirements for non- imaging data sets.
For example, instruments that make observations as individual points along an spacecraft orbit track (laser altimeters, point spectrometers)
For these types of instruments, it probably makes sense to include geometry data for each observation along track and maybe provide some summary information in the PDS labels.