IVOA Interop April 2022


Operations IG 1: Operations and Standards



Date: Tues April 26 2022, 22:00 UTC
Participants: (35)

Markus Demleitner: Requirements and Validators


LM (too tired to attend) :  You are absolutely right to say that checking non null obscore.OBS_ID values is very slow because obscore is a view. The problem is that this assertion might be true for science queries as well, and especially for queries by positions. From my point of view,  this could be a real issue for tables designed for data discovery (TapHandle developer speaking).

FB : standardized metadata are "value addition" to your services. Although the client could work without them you are missing something as a user.
With UCD, for example, the simple thing to do is to be able to display a standard definition of your data piece 



Mark Taylor: Validation for Standard Authors



LM (too tired to attend) : I've 2 remarks about the validation of XML examples in standards. 
- XML examples are usually snippets amd rarely complete documents and snippets cannot validate against a schema, one can just check the XML comformity.
- XML schemas are usually developped along with the standard, therefore using them to validate the ongoing  standard is  a sort of chicken-egg problem


Notes



Markus Demleitner: Requirements and Validators


presentation is a variation on blog post at:
https://blog.g-vo.org/requirements-and-validators.html

A "MUST" in standard has significant cost. when should it be used?

Valid reasons for MUST:

avoid MUST requirements which are really more "advice"
Importance of validating:
The smaller the immediate impact of failing a requirement, the HIGHER the importance of a validator

Mark Taylor - Validation for Authoring VO Standards


Why validate while authoring?
What to validate
Mechanics
There are VO validators out there for VOTable, UCDs and VOUnits. IVOA has a page with list of validation tools : https://wiki.ivoa.net/twiki/bin/view/IVOA/IvoaValidatorsSummary

Also XML validators out there, not just IVOA

IvoaTex Note - in production, github.com/ivoa-std/ivoatexDoc
STILTS manual

summary

James Dempsey: example of a standard that does this well?
MD: IvoaTexDoc has a few examples in the new testing section
MT: The EPN-TAP validator checks UCDs 
Tom Donaldson: Astropy has a solid VOTable validator built in
Markus Demleitner: attaching validation to doc could introduce software dependencies on the validation tool?
TD: examples, test cases in validator can help clarify the standard they are validating, resolve misunderstandings.