Design of MANGO errors: feedback expected

[Laurent Michel]

Hello DM,

(cf issue https://github.com/ivoa-std/MANGO/issues/60)

We would like get feedback from the WG about the MANGO error.

In the MANGO use cases, we have the cross-match case which requires the errors to come with statistical parameters (distribution and confidence level).

For this purpose, Mango has an abstract. datatype  with these parameters (mango:PropertyError) from which some concrete error types (e.g. ellipse …) derive.
    • Symmertrical error  1D and 2D
    • ASymmertrical error  1D
    • Ellipse error

These 4 classes have counterparts in Meas, but they have more handy attributes.
    • Individual roles for each attribute (majorAxis, minorAxis, angle) instead of value arrays [x, x, x].

These classes also have specific names in order to prevent conflicts with measure classes.

The question is to decide whether the abstract mango:PropertyError should or not derive from the astract meas:Uncertainty?
    • PRO: any Measurement error type could then be reused by Mango properties
    • CON: this will make Mango providing different error types form the same purpose (meas:ellipse or mango:PErrorEllipse)
    • CON: in our experience, cross model references are a burden for clients and particularly for annoters
    • CON: The MIVOT annotation of some Meas error classes may be tricky to interpret for the clients (attribute values in arrays).

We suggest not deriving mango:PropertyError from meas:Uncertainty.

We would like to get the group (des)agreement before opening the corresponding GIT PR

Mireille and Laurent