[Spice_discussion] Adding Surface Coverage Information to SPICE???

Charles H. Acton cacton at mailhost4.jpl.nasa.gov
Tue Mar 15 14:06:49 PST 2005

During a recent trip to Noordwijk  for a Mars Express Science 
Conference I jotted down some notes about adding surface coverage 
information to SPICE.  Here, for your consideration/comment, are 
those ideas and questions.

Chuck Acton
NAIF Manager

                     Surface Coverage Information in SPICE

How might surface coverage information be integrated into SPICE... 
particularly the plate model and digital terrain model?

*  For just one instrument:

   - it might be a simple yes or no flag
   - but more likely useful to scientists is a coverage query based on 
a set of observation geometry conditions (maybe even including 
user-supplied non-geometry conditions), such as:
       + altitude (within a range)
       + season   (within a range)
       + lighting angles (within a range)
       + ground-track surface velocity (within a range)
       + instrument operating mode
       + etc.

* Consider how to handle the above...

   - for multiple instruments on a given spacecraft
   - for multiple spacecraft

* Consider ways to represent a range of (different numbers of) hits 
within any one of the condition sets shown above.  (How deal with 
multiple conditions?)

    => varying a color as a function of # of hits seems one choice

* Consider making coverage "decisions" (i.e. covered or not covered) 
related to:

   - some sort of LAT/LON grid
   - a landmarks database
   - a geological units database
          (see http://www2.nature.nps.gov/geology/usgsnps/gmap/gmap1.html)
   - multiple of the above

(* Speaking of which, should NAIF consider implementing, or somehow 
linking to, a "geological units" database/kernel?)

*Finally, what questions along these lines did I not think of asking? 
And particularly, what might the user interface(s)--the API(s)--for 
this functionality look like?

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