EPN-TAP mandatory & regular optional parameters are in italics in the first column (the other ones are from the experimental spectroscopy and other extensions)

New parameters / ideas from workshop in dark red-brown

Usage in PDS_speclib service no longer consistent with column 3 are underlined in blue (would have to be changed also in the 2 DLR services)

Lab spectroscopy extension

 group related to:

Iterated from SSHADE and other proposals in Rome

 Initial proposal from PDS_speclib implementation


sample reference

'sample', constant

'sample', constant


Provides name of a meteorite, lunar sample, IDP, micrometeorite, etc from which the sample is extracted
- empty otherwise, no local ID

Provides an ID of the sample.
Introduces the name of a meteorite or a lunar sample when applicable.


Alternative target names/ID only - can't be used to store extra info on sample identification

not used


To provide name/ID of measured sample in local collection (agreed)

Currently included in target_name.
Various parts of the same sample can be indicated and described in sample_desc (such as "Location A", etc)


measurement origin

These two provide enough credits in the table (agreed)

 provide reference to whom measured the sample




Standard name of the lab/facility



 Name of instrument (as in publications)


sample description

provides composition as group, class, sub-class, etc… of sample, concatenated in a hash-list (=> flexible searches with LIKE and %)

Provides composition as group, class, sub-class, etc… of sample, concatenated in a hash-list (=> flexible searches with LIKE and %)


Name of mineral to be included


Must include specification "meteorite" plus the meteorite type when applicable, as well as description of (main) mixtures ingredients


Meteorite types as in Krot et al 2005.
Dana or Struntz classification tags can be used for minerals.


Minor/trace components are not welcome here (would multiply false alarms)


Min/max defined somehow, left to data provider
Proposed code for bulk = 99999

 provide the particle size range in µm


(max value not expected to be intensively used)
Proposed code for bulk = 99999

 A very large value (eg, >1000 µm) can be used locally in a service to identify bulk material
- see if we define a code for this (-1 could do, but we also have to reserve a code for N/A)

? Sample_origin ?

Need to have a separated Origin parameter ? E.g.: Natural/synthetic, etc, including "mixture"?
The drawback is the need to check several parameters 


Included in sample_classification


environment parameters

complement incidence, emergence, and phase

Azimuth angle in degrees - see if negative values of angles can have a special meaning


negative values for azi and phase have a special meaning?


unit TBC 

Experimental conditions, in bar and K.
Unit bar is not recommended by VO practices, TBC






Description of experimental conditions, free string. Measurements under vacuum are indicated here with the word "vacuum".


relative to setup

Contains UCD for this type of spectrum

The type of measurement/scale (REFF, I_over_F, etc…) provided as a UCD (being discussed at IVOA)


same, see proposed list below

such as bidirectional, biconical, directional-hemispherical, etc - see if this list can be frozen (not likely)
Can be a hash-list if composited from several spectral segments


proposed to store measurement_type in clear, associated to a specific UCD - see proposed list below
UCD proposal to be forwarded to IVOA (but doubtful…). The main benefit is to have a detailed description of complex measurements independent from UCDs

Relies on measurement_type, but accuracy of UCDs is not excepted to reach this level



free string describing the sample, its origin, and possible preparation

Free string describing the sample, its origin, and possible preparation (hash-list forbidden, as samples ID may contain # character)



Free string or hash-list describing the experimental setup if needed - may include Aperture (size of sample measured), etc



Free string or hash-list describing data post-processing / calibration


std parameters with special use

provides a link to a small spectral plot for quicklook only in VESPA portal
(larger plots to be provided as separated granules with dataproduct_type = im)

Provides a link to a small spectral plot - caution should be taken to have units / values readable in full size (will be reduced in VESPA portal)


Can contain a series of links to descriptive files providing extra information (image, text…)

Best solution to link descriptive files providing extra information (such as chemical analyses, samples images…)


Use it to store a chemical formula (alt: a list of atoms) - TBD

Comment: this parameter can be misleading if used only in some services / cases - will suggest that products not found do not exist at all

More for basic atm in obsevational data, not used here.

See if usage can be enlarged (e.g., to InChiKeys) - but for minerals?

species_inchikey ?

Check if required/useful, TBC


'sp' for spectra, but need for other values in SSHADE

'sp' for spectra

spectral_range_min (& *_max)


Provide spectral range as frequency in Hz (EPNCore standard)

spectral_sampling_step_min (& *_max)


Provide sampling step as frequency in Hz (EPNCore standard - mostly to support radio range)

spectral_resolution_min (& *_max)

spectral_resolution_min/max should instead provide 
| fq / Dfq | = | lam / Dlam | 

(agreed upon during the workshop, then checked to be consistent with other fields)

Initially provided Dfreq in EPNCore 2.0
(to be changed in next DaCHS mixin)

Other ideas:

A parameter to identify a source database in a compilation service (such as SSHADE, or PDS_speclib)

original_publisher may complement producer_name & producer_institute if required (from contributive work extension)

Uses producer_name & producer_institute to refer to original measurements

(service_title + server name) is intended to track data from another EPN-TAP service — Use of ivoID of service is more secure and would support all VO services, TBC

Photometric measurement sets?


not considered, although some are present

Optical constants: ~ two associated spectral a single file, or one / complex type? Description / table should be identical


not considered

Band lists: tables with characteristics and attributions - EPNCore is not necessarily the best solution, see later proposal


not considered

Proposed value lists, from SSHADE:

geometry_type (revised list)

direct, specular, bidirectional, directional-conical, conical-directional, biconical, directional-hemispherical, conical-hemispherical, hemispherical-directional, hemispherical-conical, bihemispherical, directional, conical, hemispherical, other geometry, unknown

PDS_speclib also contains:
biconical, off-axis
biconical, on-axis
biconical on-axis reflectance factor - this one is inconsistent

spectrum_type - revised list (UCDs to be used in data files and for measurement_type)

Spectrum_type value

UCD (existing ones only)

Comment / proposed (but do not exist)


(if it means: raw data…)




phys.absorption ??


 normalized absorbance

phys.absorption;arith.ratio ??


 optical depth


 absorption coefficient


scattering coefficient 
phys.scattering.coeff (proposed for atmospheric studies)
extinction coefficient


 refers to an integrated quantity

phys.extinction.coeff (proposed for atmospheric studies)

 optical constants


 ATR transmission


 ATR absorbance


 complex admittance

 complex impedance

 relative complex permittivity


 dielectric loss tangent

 relative complex permeability

 magnetic loss tangent

 bidirectional reflectance


= r = I/πF
Accepted Feb 2018

 bidirectional reflectance distribution function


= r / µ0 = BRDF
Weird, but agreed Feb 2018

 radiance factor


= πr = RADF = I/F
Accepted Feb 2018

 reflectance factor


= πr / µ0 = REFF
Weird, but agreed Feb 2018

 normalized reflectance


Normalized to a std wvl
(not with a coef)



 normalized Stokes parameters



 normalized Stokes parameter Q


 normalized Stokes parameter U


 normalized Stokes parameter V


 normalized Stokes parameter I


 polarization contrast

phys.polarization ??

phys.polarization.linear ??
=>reduced Pq

 degree of linear polarization


phys.polarization.linear.total ??

 polarization position angle

phys.polarization.rotMeasure ??


 degree of circular polarization


reduced Pv

 thermal emission

 thermal radiance


Can be reflected also (at least for observations)

 thermal emittance

 thermal emissivity


 scattering intensity

phys.absorption ??

phys.scattering - seems required, with subcategories (crossSection, absorption, extinction, albedo, + possibly coefficient for atm studies - TBC)

 differential scattering cross section

phys.atmol.crossSection;arith.diff ??

phys.scattering.crossSection ??

- Need arith.ang for angular distributions?

 normalized differential scattering cross section

phys.atmol.crossSection;arith.diff;arith.ratio ??

phys.scattering.crossSection;arith.ratio ??

 scattering cross section

phys.atmol.crossSection ??


 absorption cross section

phys.atmol.crossSection ??


 extinction cross section

phys.atmol.crossSection ??


 scattering efficiency factor

phys.absorption ??


(ratio of cross-section to the geometrical cross-section)

 absorption efficiency factor

phys.absorption ??


 extinction efficiency factor

phys.absorption ??


 single scattering albedo


 Raman scattering intensity

phys.raman.scattering (lesser priority)

 normalized Raman scattering intensity

phys.raman.scattering;arith.ratio (lesser priority)

 Raman scattering coefficient

phys.raman.scattering.coeff (lesser priority)

 Raman scattering efficiency

phys.raman.scattering.efficiency (lesser priority)

 fluorescence emission

phys.fluo.emission (lesser priority)

 normalized fluorescence emission

phys.fluo.emission;arith.ratio (lesser priority)

 fluorescence emission efficiency

phys.fluo.emission.efficiency (lesser priority)

Band lists





meta.id;spect;phys.atmol.transition (seen in an astro service)
 or simply
phys.atmol.transition ?

Comment: it is highly unlikely that such a detailed description can be supported with UCDs - they are not intended for this, although UCDs for some of these quantities are already defined. Raman and fluorescence related quantities are difficult to produce and have lesser priority.

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  1. liste corrigée/complétée:

    geometry_type = {direct, specular, bidirectional, directional-conical, conical-directional, biconical, directional-hemispherical, conical-hemispherical, hemispherical-directional, hemispherical-conical,  bihemispherical, directional, conical, hemispherical, other geometry, various, unknown}

  2. liste corrigée/complétée:

    spectrum_type = {raw, transmission, absorbance, normalized absorbance, optical depth, absorption coefficient, optical constants, ATR transmission, ATR absorbance, complex admittance, complex impedance, relative complex permittivity, dielectric loss tangent, relative complex permeability, magnetic loss tangent, bidirectional reflectance, bidirectional reflectance distribution function, radiance factor, reflectance factor, normalized reflectance, albedo, normalized Stokes parameter Q, normalized Stokes parameter U, normalized Stokes parameter V, polarization contrast, degree of linear polarization, polarization position angle, degree of circular polarization, thermal emission, thermal radiance, thermal emittance, thermal emissivity, scattering intensity, differential scattering cross section, normalized differential scattering cross section, scattering cross section, absorption cross section, extinction cross section, scattering efficiency factor, absorption efficiency factor, extinction efficiency factor, single scattering albedo, Raman scattering intensity, normalized Raman scattering intensity, Raman scattering coefficient, Raman scattering efficiency, fluorescence emission, normalized fluorescence emission, fluorescence emission efficiency}.

  3. UCDs with their 'Spectrum_type' (SSDM/SSHADE) equivalent:

    • phys.transmission (transmission, ATR transmission)
    • phys.absorption.coeff (absorption coefficient)
    • phys.refractIndex (optical constant)
    • phys.reflectance (radiance factor)
    • phys.reflectance.factor (reflectance factor)
    • phys.reflectance;arith.ratio (on n'a pour l'instant pas de 'normalized reflectance')
    • phys.albedo (albedo)
    • phys.polarization (polarization degree)
    • phys.polarization.linear (degree of linear polarization)
    • phys.polarization.stokes (Stokes parameter I, Stokes parameter Q, Stokes parameter U, Stokes parameter V, Stokes parameters, reduced Stokes parameter Pq, reduced Stokes parameter Pv)
    • phot.radiance (thermal radiance)
    • phys.emissivity (thermal emissivity)
    • phys.dielectric (relative complex permitivity)
    • spect.line.intensity (pour band list)

    and the one still missing:

    • phys.absorbance (absorbance, normalized absorbance, ATR absorbance, corrected ATR absorbance)
    • phys.scattering.(scattering cross section, scattering efficiency factor)
    • phys.scattering.absorption (absorption cross section, absorption efficiency factor )
    • phys.scattering.extinction (extinction cross section, extinction efficiency factor)
    • phys.raman.scattering (Raman scattering, normalized Raman scattering, Raman scattering coefficient)
    1. OK, included. + I'll put the extra ones on my shopping list for IVOA semantics (wink)

  4. Notes and suggestions:

    • reduced Pq = polarization contrast
    • reduced Pv = degree of circular polarization
    • polarization position angle: phys.polarization.rotMeasure ?? => phys.polarization.angle ?
    • polarization contrast: phys.polarization.linear?
    • degree of linear polarization: phys.polarization.linear.total ??
    • scattering intensity: phys.scattering  (not phys.absorption !)
    • differential scattering cross section: phys.scattering.crossSection;posAng ? (angular function of scattering cross section)
    • normalized differential scattering cross section: phys.scattering.crossSection;posAng;arith.ratio
    • scattering cross section: phys.scattering.crossSection
    • absorption cross section: phys.scattering.absorption.crossSection

    • extinction cross section: phys.scattering.extinction.crossSection

    • scattering efficiency factor: phys.scattering.crossSection;arith.ratio (it is the ratio of cross-section to the geometrical cross-section)
    • absorption efficiency factor: phys.scattering.absorption.crossSection;arith.ratio

    • extinction efficiency factor: phys.scattering.extinction.crossSection;arith.ratio

    • single scattering albedo: phys.scattering.albedo ?   phys.scattering;arith.ratio ?
    • Raman scattering coefficient: phys.raman.scattering.coeff
    • Raman scattering efficiency: phys.raman.scattering.efficiency ?
    • fluorescence emission: phys.fluo.emission ?

    • normalized fluorescence emission: phys.fluo.emission;arith.ratio ?

    • fluorescence emission efficiency: phys.fluo.emission.efficiency ?

    1. Thanks, this is integrated in the last table. We'll need 1) to identify those which we really need to ask for (this has to be argumented) 2) a one-line definition, accurate enough.

      The process is long and heavy, so it is better to focus on clear cases.

  5. I list below a first set, with values that are, or will be very soon, used in SSHADE + definition (as in SSDM)

    'absorbance’ => phys.absorbance:

    • : it is the common logarithm of the ratio of incident to transmitted spectral radiant power through a material (A = - log (T)).

    normalized absorbance’ => phys.absorbance;arith.ratio

    • It is the absorbance normalized to ‘1’ at a given wavelength/wavenumber/frequency,

    Polarization: here we need to have the exact definition given to the current UCDs to decide what to do for

    ‘polarization contrast’ => phys.polarization.linear ?

    • It is equal to the reduced Stokes parameter Pq which is the ratio between the Stokes parameter Q and the total intensity of light (I = I0 + I90). (Pq = Q/I)
    • Note: may be also called: reduced Stokes parameter Pq, contrast, fraction of linear polarization Q, degree of linear polarization Q. polarization (%), Q, Pq

    degree of linear polarization’: => phys.polarization.linear.total ??

    • Fraction of light which is polarized. (DolP = (Q2+U2)1/2/I)
    • Note: may be also called: total degree of linear polarization, PL, fraction of linear polarization, DoLP, mL

    polarization position angle’ => phys.polarization.angle ??

    • angle between the direction of maximum polarization and the direction perpendicular to the scattering plane. (χ= ½.atan(U/Q))

    Note: may be also called: Angle of polarization, AoP,  or position angle

    degree of circular polarization’ =>phys.polarization.circular (OK)

    • equal to the reduced Stokes parameter Pv which is the ratio between the Stokes parameter V and the total intensity of light (I = I0° + I90°). (Pv= V/I)

    Note: may be also called: reduced Stokes parameter Pv, fraction of circular polarization V, degree of circular polarization V, circular polarization (%), V, DoCP, mC

    Scattering:  used as general term for the process but also for the light scattered out of the particle

    Scattering + Absorption = Extinction

    so may be necessary to define a process 'scattering: => phys.scattering

    and then the 2 different components and their sum: Scattering, Absorption, Extinction

    scattering intensity => phys.scattering.scattering

    • intensity scattered by a medium (particles, solid, liquid) and collected by a detector

    differential scattering cross section => phys.scattering.scattering.crossSection;arith.ang ??

    • angular dependence of scattering cross section (dCsca/dα) of a particle

    normalized differential scattering cross section => phys.scattering.scattering.crossSection;arith.ratio ??

    • angular dependence of scattering cross section (dCsca/dα) of a particle normalized to its total cross section Csca

    scattering cross section => phys.scattering.scattering.crossSection

    • total scattering cross section, Csca
    • Note: It is the hemispherical integral of the differential scattering cross section’

    absorption cross section => phys.scattering.absorption.crossSection

    • total absorption cross section, Cabs
    • Note: Related with the absorption coefficient α: σ = α/N (N: molecule or particles number density)

    extinction cross section => phys.scattering.extinction.crossSection

    • sum of the absorption and scattering cross sections of a particle, Csca + Cabs

    Same for all the ‘scattering efficiency factors' (but not sure will be used soon in SSHADE) => phys.scattering.(scattering/absorption/extinction).crossSection;arith.ratio

    • defined as the ratio of the scattering/absorption/extinction cross-section to the geometrical cross-section πa2.

    single scattering albedo => phys.scattering.albedo

    • total fraction of light reflected by a single particle. It s the ratio of scattering efficiency factor to the extinction efficiency factor.

    Raman and fluorecence: intensity and normalized intensity are widely used (and in Mars rovers!), but not their scattering/emission coefficient/efficiency => low priority

    necessary to define 2 process 'Raman scattering' and 'fluorescence emission': => phys.raman & phys.fluo  or (phys.fluorescence ?)

    Raman scattering intensity’ => phys.raman.scattering

    • intensity inelastically scattered (Raman scattering) by a medium (particles, solid, liquid) and collected by a detector

    normalized Raman scattering intensity’ => phys.raman.scattering;arith.ratio

    • Raman scattering intensity normalized to ‘1’ at a given wavelength/wavenumber/frequency.

    Raman scattering coefficient => phys.raman.scattering.coeff

    • ratio of the total scattered intensity per unit distance traveled by the exciting incident beam in the scattered media to the incident intensity

    Raman scattering efficiency’ (or cross section) => phys.raman.scattering.efficiency

    • ratio of the number of photons scattered by Raman process to the total number of scattered photons

    fluorescence emission intensity’ =>  phys.fluo.emission

    • intensity emitted by fluorescence by a medium (particles, solid, liquid) and collected by a detector

    normalized fluorescence emission intensity => phys.fluo.emission;arith.ratio

    • fluorescence emission normalized to ‘1’ at a given wavelength/wavenumber/frequency

    fluorescence emission efficiency’ => phys.fluo.emission.efficiency

    • ratio of the number of photons emitted to the number of photons absorbed