Parameter: description

[mcdittmar]

I'm not sure if this issue belongs here, or in the workshop (or both).. it pertains to both modeling and the annotation.

Parameter.description: ivoa:string[1]

Model:

• first, is multiplicity 1 for an element which is often missing from serializations
• as I understand it, things like 'description' are not typically modeled elements. They do not DEFINE the object being modeled, but are merely ancillary information which may or may not be present for the benefit of a human 'reader'.
  • that does not mean that implementations would not/should not have 'description' attributes which convey any text included in the serialization. Just that whether or not this exists is a requirement on the application and has no consequence to the execution of a science thread.
• I realize this is a grey area, so am not pushing for removal, but think it is worth a conversation
  • notice that Measure and Coordinate types do not have 'description' attributes while their VOTable counterparts often do include some sort of description, however trivial (eg: from standard properties case; "Attribute managed by Saada".)

Annotation

• as a modeled element (Parameter.description) one would like to be able to annotate it directly as a COLUMN or CONSTANT, referencing the existing description of the corresponding FIELD or PARAM (or GROUP or TABLE). However, in VOTable, DESCRIPTION is just an element of other types, and cannot have an ID to reference.

[lmichel]

first, is multiplicity 1 for an element which is often missing from serializations

This still has to be checked

as I understand it,

right, the description just gives to the annoter the opportunity to say something more

I realize this is a grey area,

Mango descriptions provides it. Form a mamgo point of view, it is more logical to have descriptions in Properties (question of scope)

Annotation

Right. My annotation system propose shorcut element (prefixed by SC_) for this sort of purpose though this specific case is not taken into consideration for now. This feature has been required by Gilles

[mcdittmar]

So, this may be important in our discussion about the annotation syntax.

• it's a capability that the Mapping proposal does not have. You cannot annotate content within the VOTable atom (description, array cells, etc.)
• the trick may be in deciding if it should. If the 'need' is based on accessing VOTable content which can reasonably be considered modeled content. (and description may not be the best example), then the annotation should accommodate it.
• the alternative being to say this is not a model concept, but address it in the annotation. "Any object may have a description. If supported by the implementation, the value is pulled from the VOTable DESCRIPTION sub-node of the associated PARAM|FIELD|TABLE" (we don't annotate GROUPs I think).

Hmm.. I just read through the description of the SC* elements, and don't see how these help in annotating content within the VOTable atom. The description looks like it consolidates a group of ATTRIBUTE nodes to populate a full ivoa:Quantity with one annotation tag. In the Mapping syntax, this is not necessary since LITERAL, CONSTANT and COLUMN can populate the full Quantity. I don't think the SC* tag helps unless the description is independently serialized in its own PARAM|FIELD, in which case it is referable and not a problem.

I've added a note into the Wiki for your implementations https://github.com/ivoa/dm-usecases/wiki/mango.

On Fri, Mar 12, 2021 at 8:36 AM Laurent MICHEL @.***> wrote:

Annotation

Right. My annotation system propose shorcut element (prefixed by SC_) for this sort of purpose though this specific case is not taken into consideration for now. This feature has been required by Gilles

[lmichel]

This is a good point.

SC_FIELD could carry the DESCRIPTION but it is better to allow to get that description by a specific tag. I like you proposal:

"Any object may have a description. If supported by the implementation, the value is pulled from the VOTable DESCRIPTION sub-node of the associated PARAM|FIELD|TABLE" (we don't annotate GROUPs I think).

Another option would be to add a new Element to the syntax <DESCRIPTION dmrole=description ref="col#4"> instead of <ATTRIBUTE dmrole=description ref=???>

or <ATTRIBUTE dmrole=description ref=col#4 ele=desc> ele can by desc/ucd/unit

[Bonnarel]

Having "descriptions" attributes in the model is not dependent from the annotation mechanism in VOTable. Or should not. Any serialization should allow to retrieve description by the same kind of method print (Model.get(mod:instance.description)) Provenance model also have "descriptions" attributes for activities and entities called "comments". This is a text explaining what the entity/activity is all about (not to be confused with ActivityDescription which is a class gathering features shared by many activities)