UCD vocabulary revision : first iteration of the maintance procedure

[Stéphane Erard]

Dear Mireille and all

I think some elements of the original requests got lost in the process. 

Le 21 mai 2018 à 00:30, Mireille Louys <mireille.louys at unistra.fr> a écrit :

> Dear Semantics , dear tcg members 
> 
> The Semantics has proposed a Maintenance procedure in oder to update the UCD list ( and more generaly ivoa vocabularies) 
> as stated in the WD http://www.ivoa.net/documents/UCDlistMaintenance/20171018/
> 
> We are experiencing the first iteration of this procedure.
> 
> Here is the list of new terms asked during the last revision iteration for UCD terms asked for the period  "May 2017 - Feb2018"
>  23 terms have been proposed, discussed in the UCD expert group and inserted in the UCD assigning tool.
>  
>   Q | phys.electCharge | Electric charge 
>   Q | phys.current | Electric current
>   Q | phys.current.density | Electric current density
>   Q | pos.incidenceAng | Incidence angle of optical ray on an interface
>   Q | pos.emergenceAng | Emergence angle of optical ray on an interface
>   Q | pos.azimuth | azimuthal angle in a generic reference plane

My original proposal was pos.azimuthAng 
Is there a reason to have a syntax different from the other angles? (pos.phaseAng which is related has been there for a long time) 
A more specific definition is
	Angle between illumination and viewing directions projected on the horizontal plane

>   Q | phys.reflectance | Radiance factor (received radiance divided by input radiance)

This description is not very precise: Radiance factor or I/F (radiance over normal solar flux)
 (to make it short…)

>   Q | phys.reflectance.bidirectional | Bidirectional reflectance
>   Q | phys.reflectance.bidirectional.df | Bidirectional reflectance distribution function

This one is a misunderstanding: "distribution function" is not a subtype of bidirectional reflectance (and has nothing to do with a probability distribution function). Instead, both bidirectional and brdf (= bidirectional reflectance distribution function) are subtypes of reflectance. brdf is a standard acronym in the interested community.
I suggest instead to have
 Q | phys.reflectance.bidirectional | Bidirectional reflectance (as proposed)
 Q | phys.reflectance.brdf | Bidirectional reflectance distribution function
If this is an issue, the first one has priority


>   Q | phys.reflectance.factor | Reflectance normalized per direction cosine of incidence angle
>   S |pos.cylindrical |Related to cylindrical coordinates
>   Q | pos.cylindrical.r | Radial distance from z-axis (cylindrical coordinates)
>   Q | pos.cylindrical.azi | Azimuthal angle around z-axis (cylindrical coordinates)
>   Q | pos.cylindrical.z | Height or altitude from reference plane (cylindrical coordinates)
>   S | pos.spherical | Related to cylindrical coordinates
	… to Spherical …

>   Q | pos.spherical.r | Radial distance or radius (spherical coordinates)
>   Q | pos.spherical.azi | Azimuthal angle (spherical coordinates)
>   Q | pos.spherical.colat |Polar or Colatitude angle (spherical coordinates)
>   Q | pos.resolution | Spatial linear resolution (not angular)
>   S | pos.bodycentric | Body-centric related coordinate
>   S | pos.bodygraphic | Body-graphic related coordinate
>   Q | meta.checksum | Numerical signature of digital data
>   Q | phys.polarization.coherency | Matrix of the correlation between components of an electromagnetic wave
> 
> The full detailed discussion is available at the dedicated web page  http://wiki.ivoa.net/twiki/bin/view/IVOA/UCDList1dot42017June2018FebRFM
> We would like to have these terms agreed by the TCG in order to validate UCD List version 1.4 
> 
> Please revise this list and express your comments. 
> Many thanks , 
> Mireille (Semantics WG chair)
> 
> 

Cheers
Stéphane