Unit for Okta is missing

[Jeffrey-Vervoort-KNMI]

The unit for the measurement of cloud cover is not currently available in the vocabulary. Would it be acceptable for this project if I create a PR to add "Okta" as a unit?

I noticed that there are some guides over here, for when I would be allowed to contribute:

• https://github.com/qudt/qudt-public-repo/wiki/GoodGitPractices
• https://github.com/qudt/qudt-public-repo/wiki/Unit-Vocabulary-Submission-Guidelines

[fkleedorfer]

Thanks for this suggestion and the offer to make a PR!

It seems like Okta would be a new qudt:Unit, and that it would require the addition of a new qudt:QuantityKind, for example AmountOfCloudCover or CloudCoverIntensity, which would be the qudt:quantityKind of the new unit.

If I understand correctly, the value range would be an integer in [0, 1,2,3,4,5,6,7,8]. I am not sure how we would express that - but @steveraysteveray @jhodgesatmb @ralphtq will weigh in on that.

[Jeffrey-Vervoort-KNMI]

The range is slightly larger and includes the value 9, which indicates that the sky is obstructed from view. This obstruction can occur for various reasons, such as fog or an absence of detection. Unlike values 0 to 8, which represent levels of cloudiness –where 0 means no clouds, 1 indicates a few or less clouds, ... 4 represents a half-clouded sky, ... 8 means completely clouded – 9 stands out as a categorical value. I don't know, but hope not that that would make it more complex.

[jhodgesatmb]

As a unit the Okta should be straight forward as a PR. It can be associated with a Scale with values defined in an ordinal enumeration, 0-9. I do not recall whether our PR instructions talk about creating scales/enumerations.

…

On Fri, Nov 29, 2024 at 5:26 AM Jeffrey-Vervoort-KNMI < ***@***.***> wrote: The range is slightly larger and includes the value 9, which indicates that the sky is obstructed from view. This obstruction can occur for various reasons, such as fog or an absence of detection. Unlike values 0 to 8, which represent levels of cloudiness –where 0 means no clouds, 1 indicates a few or less clouds, ... 4 represents a half-clouded sky, ... 8 means completely clouded – 9 stands out as a categorical value. I don't know, but hope not that that would make it more complex. — Reply to this email directly, view it on GitHub <#1047 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AATQRWLUKN3Y66WS5URMEKT2DBTO7AVCNFSM6AAAAABSVA5MQSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKMBXHAYTONBZGY> . You are receiving this because you were mentioned.Message ID: ***@***.***>

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[jhodgesatmb]

I agree with @fkleedorfer that this should be implemented as a qudt:Unit following normal PR submission guidelines conventions, and that a corresponding QuantityKind should be created. The Okta is a measurement of 'cloudiness' and, according to: https://windy.app/blog/okta-cloud-cover.html, @fkleedorfer's suggestion of 'AmountOfCloudCover' seems the most compatible. For now we should not implement a range restriction as that would be on the quantity side, though the resource quoted above even includes a value of 10 (i.e., 0-10 rather than 0-9), for 'no measurment taken'.

[steveraysteveray]

I'm finally catching up with various discussions. This specific example has great similarity with how we treated unit:RichterMagnitude, which has a quantity kind of quantitykind:EarthquakeMagnitude. I suggest we follow the same pattern. Note that we did not attempt to define the actual values on the Richter scale. Also note the lack of a qudt:conversionMultiplier triple.

[steveraysteveray]

Mind you, to be consistent with our naming convention, our unit should be renamed to unit:MAGNITUDE_RICHTER I think.

[Jeffrey-Vervoort-KNMI]

Do I understand it correctly that it should become something like the following?

Unit:

unit:OKTA
  a qudt:Unit ;
  dcterms:description "\"Okta\" is the unit of measurement describing the amount of cloud cover. Okta is reported in eighths of the celestial dome covered by all clouds visible. The codes represent 0: 0/8, the complete absence of cloud; 1: 1/8 or less, but not zero; 2: 2/8; 3: 3/8; 4: 4/8, half of the sky is covered; 5: 5/8; 6: 6/8; 7: 7/8 or more, but not 8/8; 8: 8/8, sky is completely covered; 9: Sky obscured by fog and/or other meteorological phenomena; /: Cloud cover is indiscernible for reasons other than fog or other meteorological phenomena, or observation is not made."^^rdf:HTML ;
  qudt:conversionMultiplier 1.0 ;
  qudt:conversionMultiplierSN 1.0E0 ;
  qudt:hasDimensionVector qkdv:A0E0L0I0M0H0T0D1 ;
  qudt:plainTextDescription "\"Okta\" is the unit of measurement to describe the amount of cloud cover. Okta is reported in eighths of the celestial dome covered by all clouds visible. The codes represent 0: 0/8, the complete absence of cloud; 1: 1/8 or less, but not zero; 2: 2/8; 3: 3/8; 4: 4/8, half of the sky is covered; 5: 5/8; 6: 6/8; 7: 7/8 or more, but not 8/8; 8: 8/8, sky is completely covered; 9: Sky obscured by fog and/or other meteorological phenomena; /: Cloud cover is indiscernible for reasons other than fog or other meteorological phenomena, or observation is not made." ;
  qudt:hasQuantityKind quantitykind:AmountOfCloudCover ;
  qudt:informativeReference "https://windy.app/blog/okta-cloud-cover.html" ;
  qudt:isoNormativeReference "https://library.wmo.int/viewer/68695/?offset=3#page=514&viewer=picture&o=bookmark&n=0&q=" ;
  rdfs:isDefinedBy <http://qudt.org/2.1/vocab/unit> ;
  rdfs:label "Okta"@en ; .

Quantity kind:

quantitykind:AmountOfCloudCover
  a qudt:QuantityKind ;
  qudt:hasDimensionVector qkdv:A0E0L0I0M0H0T0D1 ;
  qudt:isoNormativeReference "https://library.wmo.int/viewer/68695/?offset=3#page=514&viewer=picture&o=bookmark&n=0&q=" ;
  qudt:plainTextDescription "The amount of the celestial dome covered by all clouds visible." ;
  rdfs:isDefinedBy <http://qudt.org/2.1/vocab/quantitykind> ;
  rdfs:label "Amount of cloud cover"@en .

[steveraysteveray]

If you remove the conversion multiplier triples (because the scale is not linear) it looks pretty good to me. I (or you) would need to run the validator to be sure.

[jhodgesatmb]

According to the web page there is also a value of 10, which is associated with not having taken any measurements at all. Although this raises the question about how measurements fit into QUDT (if at all), it at least is part of the definition as far as I can tell. I would suggest adding this to the description.

[fkleedorfer]

Are you comfortable with forking and making a PR?

[steveraysteveray]

Adding to @fkleedorfer's question, I would add that we recently clarified our procedures for making contributions. See, for example, our expanded https://github.com/qudt/qudt-public-repo/wiki/GoodGitPractices wiki page.

[Jeffrey-Vervoort-KNMI]

@jhodgesatmb I added the value 10 as a / to be consistent with the descriptions of WMO and windy.app. Would that be an issue?