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Actionfromtopurposestatus / answer

Check here for recent discussions (mostly the first one which addresses these questions): 
https://wiki.ivoa.net/twiki/bin/view/IVOA/UCDList_1-4_2017Jun_2018Feb_RFM
https://wiki.ivoa.net/twiki/bin/view/IVOA/RFMforUCD
https://wiki.ivoa.net/twiki/bin/view/IVOA/UCDList_1-3_RFM





Coordinates:

• pos.bodyrc needs to be used as primary (relates to body coord system, as pos.lunar)

SE



Not needed

Maps:
• At least a new pos.projection is required to introduce projection/mapping scheme (there is currently only a very specific pos.lambert). Possible values as in fits, extended to support georeferentiation (Marmo et al 2018)

SE
Also required to introduce projection parameters using various standards (Proj4…)
• UCD needed for VOeventsSE


• Clarify usage of inf / -inf / Nan in ADQL (should apparently exist, as per DALI - but do not)SE


• Correct/clarify definition of reflectance in 2018 RFM sheet: 
add Q | phys.reflectance | Radiance factor (received radiance divided by input radiance)

Radiance factor is the same as I/F; in this case, this is divided by input irradiance (not radiance), i.e. by solar flux.

Can we can keep phys.reflectance for the reflectance factor (standard quantity for lab measurements, currently listed as phys.reflectance.factor)  = ratio of radiance to that of a Lambertian disk at the same distance and illuminated under the same incidence (also called radiance coefficient)? - no, this is only a mess…

In any case, this is not necessarily similar to albedo (which is typically integrated spectrally/in angular domain, and is then related to thermal equilibrium). I would keep albedo for more general purpose.

SE


• Correct/clarify brdf in 2018 sheet: 

addQ | phys.reflectance.bidirectional.df| Bidirectional reflectance distribution function

The UCD is very weird, would better be phys.reflectance.brdf (this is not a subset of .bidirectional)
definition: Ratio of radiance to incident normal solar flux





• Suggestion for reflectance in 2018 RFM sheet, to be corrected: 

for normalized reflectance concept: proposal arith.ratio;phys.reflectance 
definition : reflectance normalized per reflectance at one wavelength 

=> Should be arith.factor;phys.reflectance

SE


How do we handle hemispherically integrated quantities?SE
reflectance / emission
posAng is commonly mistaken for a generic UCD for angles (which does not exist). Make definition more explicit (e.g., Free dictionary: thedirectioninwhichoneobjectliesrelativetoanotheronthecelestialsphere,measuredindegrees fromnorthinaneasterlydirection)



Section 8, 2 (about pos): 

"the angular size of an object is in this section, its linear size is in the phys section)"

But we have phys.angSize (with an unclear definition) )- should be in pos?

SE


On the same token, 

phys.angVeloc would look more consistent than phys.veloc.ang

SE


Additional set of UCDs for spectroscopy. In particular, a category phys.scattering seems required, see here

+ arithm.ang could do for angular distributions

SE


How do we handle asymmetric error bars? Some services need to have stat.error.min/max SE

use stat.error;stat.min
stat.error;stat.max
How do we specify an additive constant or offset? The only close match is arith.zp, which is context specific (for magnitude scales)SE
At least enlarge the definition to any type of offset / additive constant
Add JSON output to TAP standard?SE
must be faster than VOtable (critical in the VESPA portal)
SAMP only pass the first table resource of a VOtable, seems to be in the standard - although TOPCAT can actually open all tables when provided directly. Why that? SEMark TaylorThis is a problem to send VizieR catalogues from VESPA portal (but also from TAPhandle).askedDone on purpose. The solution is to send table resources one by one from the interface.