Have human-readable labels on instances that may need UI choices

[msdemlei]

In many applications user agents will want to present a choice of using different instances in a UI. For example, there could be several positions per table row, or perhaps several photometric measurements (Kron vs. aperture). In these cases, it is helpful for the user agent to have a hint on how to present this choice.

So, when a coordinate has such a human-readable label, a UA could show a selector for, say,

"Short-term solution/Long-term solution/Galactic"

rather than the less helpful

"Coord in ICRS 1/Coord in ICRS 2/Coord in Galactic 1"

[lmichel]

This is implemented by MANGO at parameter level. There are 2 fields giving precision on the parameter nature:

• one vocabulary tag
• One text descriptor that can either be set as a reference tp the FIELD descriptor or written as a literal.

For the record, the first MANGO draft had a third field specifying the reduction status of the measure (calibrated, computed...). It has been withdrawn because it is often difficult to get from archival datasets.