Define pre-met file content and structure

[juliacollins]

Describe the "pre-met" information needed to generate UMM-G files.

[juliacollins]

A few thoughts, although we may not need to worry about these input files for the MODSCG use case. Collections with Orbit spatial domains not considered in the notes below.

Information we need, applies to all granules:
Authoritative ID and version number for the collection
The "Horizontal Spatial Domain" (we may be able to use the GranuleSpatialRepresentation value from the collection metadata)
Whether additional spatial processing is needed (e.g. create a concave hull around the granule's points)

Information we need for each granule:
Spatial coordinates
Temporal extent
DayNightFlag (if something besides the default of Unspecified)
Production data/time for the granule
If the granule includes more than one science file, or related files are included (such as a browse file), we will need to describe that situation somehow.

[lisakaser]

@juliacollins It is my understanding after our brainstorm session last week that for MODSCAGS we would rely on reading information from the netcdf files and set all other flags in the app's config/ini file. So this ticket seems lower in priority now. I will keep it open in this sprint to confirm with you.