EPN-TAP V2.0 parameters

List of EPN-TAP parameters
(refreshed/completed April 2019) (SE)

EPN-TAP

EPN-TAP is a VO access protocol dedicated to Planetary Science data. It is based on the TAP mechanism from IVOA, completed with sets of parameters and associated lists of values. In this regard, it is similar to ObsTAP but with a different scope.
EPN-TAP version 2 is a major update of the protocol to accommodate larger services and simplify setup and use of data services. All parameters are described here.

Parameters which must be provided

are now clearly identified - those are not only mandatory, they also must provide a value.
They are mostly related to service description and granule identification.

+ See notes below the table.

Thematic extensions

Some science fields will require optional parameters, which need to be used consistently between services addressing the same field. Such extensions have to be designed by sub-groups involved in the corresponding data services, either as providers or users. This includes:

Lab spectroscopy: parameters to describe mineralogical samples (and possibly other samples)
Solar System objects: covers orbital/rotational parameters, physical properties, and taxonomy
APIS: contains parameters for observing programs
Contributive works / observing programs: enlargement of APIS extension to other data
Exoplanets / planetary systems properties
Map extension (to be enlarged)
Events: covers the VOevent standard and other types of events
Particle spectroscopy (to be finalized)
Results of planetary 3D modelling run (in progress)
Bibliographic entries? May be manageable otherwise, through bibcode / doi interpretation

Name, v2	Value required (not NULL)?	SQL type	Unit / Format / Range	Description	UCD	UCD in Obscore 1.1 (9/5/2017 REC version)	Utype (tentative)	Comments
EPNCore mandatory parameters (Must be present, possibly empty)					Current value current but dubious or undefined check this (dubious)	— ? : closest sense _ : N/A in ObsCore	from epntap v2 mixin (aug 2017) equivalent/close in ObsCore doc 1.1
granule_uid	Y	Text		Unique ID in data service.	meta.id	meta.id		Can be alphanum.
granule_gid	Y	Text		Common to granules of same type	meta.id	meta.id		E.g. same map projection, or geometry data products. Can be alphanum.
obs_id	Y	Text		Associates granules derived from the same data	meta.id;obs	meta.id	obscore:DataID.observationID	E.g. various representations / processing levels. Can be alphanum., may be the ID of original observation. Keep it simple in intricate situations.
dataproduct_type	Y	Text		Organization of the data product, from enumerated list	meta.code.class	meta.id	Epn.dataProductType obscore:ObsDataset.dataProductType
target_name		Text		Standard IAU name of target (from a list related to target class), case sensitive.	meta.id;src	meta.id;src	Epn.TargetName	Case sensitive Services with no target_name do exist
target_class	Y	Text		Type of target, from enumerated list	src.class	src.class	Epn.TargetClass
time_min		Double	d (date as JD)	Start time (in JD). UTC measured at time_origin location (default is observer's frame)	time.start;obs	time.start;obs.exposure	Char.TimeAxis.Coverage.Bounds.Limits.Interval.StartTime TBD (from ObsCore)
time_max		Double	d (date as JD)	Stop time (in JD). UTC measured at time_origin location (default is observer's frame)	time.end;obs	time.end;obs.exposure	Char.TimeAxis.Coverage.Bounds.Limits.Interval.StopTime TBD (from ObsCore)
time_sampling_step_min		Double	s	Min time sampling step	time.resolution;stat.min	time.resolution	Epn.Time.Time_sampling_step_min
time_sampling_step_max		Double	s	Max time sampling step	time.resolution;stat.max		Epn.Time.Time_sampling_step_max
time_exp_min		Double	s	Min integration time	time.duration;obs.exposure;stat.min	time.duration;obs.exposure	Epn.Time.Time_exp_min
time_exp_max		Double	s	Max integration time	time.duration;obs.exposure;stat.max		Epn.Time.Time_exp_max
spectral_range_min		Double	Hz	Min spectral range (frequency)	em.freq;stat.min	em.wl;stat.min (always as wl)	Epn.Spectral.Spectral_range_min	Always as freq
spectral_range_max		Double	Hz	Max spectral range (frequency)	em.freq;stat.max	em.wl;stat.max	Epn.Spectral.Spectral_range_max
spectral_sampling_step_min		Double	Hz	Min spectral sampling step	em.freq.step;stat.min	meta.number	Epn.Spectral.Spectral_sampling_step_min
spectral_sampling_step_max		Double	Hz	Max spectral sampling step	em.freq.step;stat.max	meta.number	Epn.Spectral.Spectral_sampling_step_max
spectral_resolution_min		Double		Min spectral resolution (resolving power)	spect.resolution;stat.min	spect.resolution (relates to resolving power)	Epn.Spectral.Spectral_resolution_min	Now (2019) provides resolving power \|(lambda / delta(lambda)\| = \|f /Df\| How do we accommodate FWHM for filters?
spectral_resolution_max		Double		Max spectral resolution (resolving power)	spect.resolution;stat.max		Epn.Spectral.Spectral_resolution_max	Now (2019) provides resolving power \|(lambda / delta(lambda)\| = \|f /Df\| How do we accommodate FWHM for filters?
c1min		Double	(1) Longitude from 0. to 360. RA from 0. to 24.	Min of first coordinate	pos;stat.min pos.distance;stat.min (bof) or pos.radius;stat.min (does not exist) for spherical & cylindrical pos.eq.ra;stat.min for celestial pos.bodyrc.lon;stat.min for body pos.cartesian.x;stat.min for Cartesian pos.healpix for healpix (with 2 parameters? - weird) - TBC empty ("") for none (and no unit)	pos.eq.ra	Epn.Spatial.Spatial_range.c1min	Typo in current mixin (.lonG => .lon
c1max		Double	(1)	Max of first coordinate	pos;stat.max, etc		Epn.Spatial.Spatial_range.c1max
c2min		Double	(1) Latitude from -90. to +90.	Min of second coordinate	pos;stat.min pos.angDistance;stat.min or pos.az.zd;stat.min (for zenithal distance) for spherical or pos.az.azi;stat.min (for azimuth) for cylindrical pos.eq.dec;stat.min for celestial pos.bodyrc.lat;stat.min for body pos.cartesian.y;stat.min for Cartesian empty ("") for none (and no unit)	pos.eq.dec	Epn.Spatial.Spatial_range.c2min
c2max		Double	(1)	Max of second coordinate	pos;stat.max, etc		Epn.Spatial.Spatial_range.c2max
c3min		Double	(1)	Min of third coordinate	pos;stat.min pos.AngDistance;stat.min or pos.az.azi;stat.min (for azimuth) for spherical pos.distance;stat.min for cylindrical pos.distance;stat.min for celestial pos.bodyrc.alt;stat.min for body? (from surface only, implicitly from reference level) or pos.distance;pos.bodyrc;stat.min for body (from center)? pos.cartesian.z;stat.min for Cartesian empty ("") for none (and no unit)		Epn.Spatial.Spatial_range.c3min
c3max		Double	(1)	Max of third coordinate	pos;stat.max, etc		Epn.Spatial.Spatial_range.c3max
s_region		spoly	PgSphere spoly	ObsCore-like footprint for celestial, spherical, or body-fixed frames.	phys.outline;obs.field	phys.outline;obs.field	obscore:Char.SpatialAxis.Coverage.Support.Area	(was initially instr.fov, to be corrected) ObsCore value updated (was phys.angArea;obs) Frame may be identified in q.rd (UNKNOWNFrame). Use value given in spatial_frame_type - very unclear… Do we need another param for GIS interface?
c1_resol_min		Double	(1)	Min resolution in first coordinate	pos.resolution;stat.min if linear pos.angResolution;stat.min if angular	pos.angResolution;stat.min	Epn.Spatial.Spatial_resolution.c1_resol_min	pos.resolution restored in 2018 In body fixed frame, use pixelscale_min/max for resolution at the surface
c1_resol_max		Double	(1)	Max resolution in first coordinate	pos.resolution;stat.max if linear pos.angResolution;stat.max if angular	pos.angResolution;stat.max	Epn.Spatial.Spatial_resolution.c1_resol_max	_
c2_resol_min		Double	(1)	Min resolution in second coordinate	pos.resolution;stat.min if linear pos.angResolution;stat.min if angular		Epn.Spatial.Spatial_resolution.c2_resol_min	_
c2_resol_max		Double	(1)	Max resolution in second coordinate	pos.resolution;stat.max if linear pos.angResolution;stat.max if angular		Epn.Spatial.Spatial_resolution.c2_resol_max	_
c3_resol_min		Double	(1)	Min resolution in third coordinate	pos.resolution;stat.min if linear pos.angResolution;stat.min if angular (spherical only)		Epn.Spatial.Spatial_resolution.c3_resol_min	pos.resolution restored in 2018
c3_resol_max		Double	(1)	Max resolution in third coordinate	pos.resolution;stat.max if linear pos.angResolution;stat.min if angular (spherical only)		Epn.Spatial.Spatial_resolution.c3_resol_max	pos.resolution restored in 2018
spatial_frame_type	Y	Text	(1)	Flavor of coordinate system, defines the nature of coordinates. From enumerated list. Use "none" if undefined.	meta.code.class;pos.frame	_		A value is required by DaCHS (query will return errors if empty) Default value = none
incidence_min		Double	deg	Min incidence angle (solar zenithal angle)	pos.incidenceAng;stat.min	_	Epn.View_angle.Incidence_angle_min	UCD for angles included in 2018
incidence_max		Double	deg	Max incidence angle (solar zenithal angle)	pos.incidenceAng;stat.max	_	Epn.View_angle.Incidence_angle_max	UCD for angles included in 2018
emergence_min		Double	deg	Min emergence angle	pos.emergenceAng;stat.min	_	Epn.View_angle.Emergence_angle_min	UCD for angles included in 2018
emergence_max		Double	deg	Max emergence angle	pos.emergenceAng;stat.max	_	Epn.View_angle.Emergence_angle_max	UCD for angles included in 2018
phase_min		Double	deg	Min phase angle	pos.phaseAng;stat.min		Epn.View_angle.Phase_angle_min
phase_max		Double	deg	Max phase angle	pos.phaseAng;stat.max		Epn.View_angle.Phase_angle_max
instrument_host_name		Text		Standard name of the observatory or spacecraft	meta.id;instr.obsty	meta.id;instr.tel	Provenance.ObsConfig.Facility.name
instrument_name		Text		Standard name of instrument	meta.id;instr	meta.id;instr	Provenance.ObsConfig.Instrument.name
measurement_type		Text		UCD(s) defining the data	meta.ucd	meta.ucd	Epn.Measurement_type	Add ;meta.modelled if simulation or model Add ;stat.uncalib if uncalibrated data - in which case processing_level must be 0 or 1
processing_level		Integer		Dataset-related encoding, or simplified CODMAC calibration level	meta.calibLevel	meta.code;obs.calib	~ obscore:ObsDataset.calibLevel	To be replaced by PDS4 values in v2.1?
creation_date	Y	Timestamp	(ISO-8601 String)	Date of first entry of this granule	time.creation	time;meta.dataset
modification_date	Y	Timestamp	(ISO-8601 String)	Date of last modification	time.processing			Used to handle mirroring UCD value being discussed in 2018
release_date	Y	Timestamp	(ISO-8601 String)	Start of public access period (set to creation_date if no proprietary period)	time.release	time.release	obscore:Curation.releaseDate	The value is in ISO 8601 format reusing this pattern: (“YYYY-MM-DDThh:mm:ss”) If release_date is in the future, the data is proprietary.
service_title	Y	Text		Title of resource = schema name	meta.title			May be used to handle multiservice results
Common optional parameters
access_url		Text		URL of the data file, case sensitive (additional files may be linked through datalink_url). Can point to a script. If present, next 2 parameters must also be present.	meta.ref.url;meta.file	meta.ref.url	Obs.Access.Reference	Use this to link data! Could accommodate a datalink with access_format = 'application/x-votable+xml;content=datalink' (from ObsCore) - but this is a funny idea…
access_format		Text	(mime type in lowercase)	File format type	meta.code.mime	meta.code.mime	Obs.Access.Format
access_estsize		Integer	kbyte	Estimate file size in kbyte (with this spelling)	phys.size;meta.file	phys.size;meta.file	Obs.Access.Size
access_md5		Text		MD5 Hash for the file when available (real file, not script)	meta.checksum;meta.file
thumbnail_url		Text		URL of a thumbnail image with predefined size (png ~200 pix, for use in a client only)	meta.ref.url;meta.preview
file_name		Text		Name of the data file only, case sensitive	meta.id;meta.file	meta.title;obs — ?		ObsCore obs_title is for a short free text string describing the granule. Do we want this?
datalink_url		Text	(url)	Provides links to files or services on the server	meta.ref.url;meta.datalink			Associated mime-type is 'application/x-votable+xml;content=datalink' (from ObsCore)
species		Text		Identifies a chemical species, case sensitive	meta.id;phys.atmol			This is the only case sensitive parameter (with target_name)
waveband		Text		Electro-magnetic band, from enumerated list	instr.bandpass
alt_target_name		Text	can be a hash list	Provides alternative target name if more common	meta.id;src
target_region		Text		Type of region or feature of interest	obs.field
feature_name		Text		Secondary name (e.g. standard name of a region of interest)	obs.field
publisher		Text		Resource publisher	meta.curation	meta.ref.uri;meta.curation	~ obscore:Curation.publisherID
bib_reference		Text		Bibcode or doi preferred; can be URL or anything else	meta.bib	meta.bib	obscore:Curation.reference	Bibcode & doi can be completed in TOPCAT
internal_reference		Text		Related granule_uid(s) in the current service	meta.id.cross			Use to link one granule to a set of other granules. To be used only if required - e.g. to solve situations that would otherwise require several tables
external_link		Text	(url)	Web page providing more details on the granule.	meta.ref.url			Link to an individual page in a web site associated to the database, e.g., a planet page in Exoplanets service. This is a way to provide extra granule information which cannot be accommodated in the table.
spatial_coordinate_description		Text		ID of specific coordinate system and version / properties	meta.code.class;pos.frame			~COOSYS, but includes planetary ones Still TBD. Discussion in progress here: EPN-TAP v2: Current discussion topic
spatial_origin		Text		Defines the frame origin	meta.ref;pos.frame
time_origin		Text		Defines where the time is measured (e. g., ground vs spacecraft)	meta.ref;time.scale			target_time is of course always on target.
time_scale		Text		Always UTC in data services - from enumerated list	time.scale
subsolar_longitude_min		Double	deg	Minimum sub-solar point longitude	pos.bodyrc.lon;stat.min			Provided in the most natural body-related coordinate frame, E-handed - seems to require 'body'
subsolar_longitude_max		Double	deg	Maximum sub-solar point longitude	pos.bodyrc.lon;stat.max			Provided in the most natural body-related coordinate frame, E-handed - seems to require 'body'
subsolar_latitude_min		Double	deg	Minimum sub-solar point latitude	pos.bodyrc.lat;stat.min			_
subsolar_latitude_max		Double	deg	Maximum sub-solar point latitude	pos.bodyrc.lat;stat.max			_
subobserver_longitude_min		Double	deg	Minimum sub-observer point longitude (sub-Earth for ground based observations)	pos.bodyrc.lon;stat.min			_
subobserver_longitude_max		Double	deg	Maximum sub-observer point longitude (sub-Earth for ground based observations)	pos.bodyrc.lon;stat.max			_
subobserver_latitude_min		Double	deg	Minimum sub-observer point latitude (sub-Earth for ground based observations)	pos.bodyrc.lat;stat.min			_
subobserver_latitude_max		Double	deg	Maximum sub-observer point latitude (sub-Earth for ground based observations)	pos.bodyrc.lat;stat.max			_
ra		Double	deg	Right ascension	pos.eq.ra;meta.main			deg only (like ObsCore)
dec		Double	deg	Declination	pos.eq.dec;meta.main
radial_distance_min		Double	km	Min distance from center (in body-fixed frame)	pos.distance;pos.bodyrc;stat.min
radial_distance_max		Double	km	Max distance from center (in body-fixed frame)	pos.distance;pos.bodyrc;stat.max
altitude_fromshape_min		Double	km	Min altitude above shape model / DTM (in body-fixed frame)	pos.bodyrc.alt;stat.min
altitude_fromshape_max		Double	km	Max altitude above shape model / DTM (in body-fixed frame)	pos.bodyrc.alt;stat.max
solar_longitude_min		Double	deg	Min Solar longitude Ls (location on orbit / season)	pos.ecliptic.lon;pos.heliocentric;stat.min
solar_longitude_max		Double	deg	Max Solar longitude Ls (location on orbit / season)	pos.ecliptic.lon;pos.heliocentric;stat.max
local_time_min		Double	h	Min local time at observed region	time.period.rotation;time.phase;stat.min
local_time_max		Double	h	Max local time at observed region	time.period.rotation;time.phase;stat.max
target_distance_min		Double	km	Min observer-target distance	pos.distance;stat.min
target_distance_max		Double	km	Max observer-target distance	pos.distance;stat.max
target_time_min		Timestamp	(ISO-8601 String)	Min observing time in target frame	time.start;src			(simplest way to look for coordinated observations)
target_time_max		Timestamp	(ISO-8601 String)	Max observing time in target frame	time.end;src
earth_distance_min		Double	au	Min Earth-target distance	pos.distance;stat.min
earth_distance_max		Double	au	Max Earth-target distance	pos.distance;stat.max
sun_distance_min		Double	au	Min Sun-target distance	pos.distance;stat.min
sun_distance_max		Double	au	Max Sun-target distance	pos.distance;stat.max
Parameters from extensions
obs_mode		Text		Observing mode	meta.code;instr.setup			From APIS + observation extensions (with adapted UCDs)
detector_name		Text		Detector name	meta.id;instr.det
opt_elem		Text		Optical element name	meta.id;instr.param
filter		Text		Identifies filter in use, typically for images	meta.id;instr.filter			Informative only, free format (no list, but see http://svo2.cab.inta-csic.es/svo/theory/fps3/). Search can only rely on spectral range, as ObsCore does.
instrument_type		Text		type of instrument	meta.id;instr			Informative only (not a reliable search parameter): free format, no reference list intended.
acquisition_id		Text		ID of the data file/acquisition in the original archive	meta.id
proposal_id		Integer		Proposal identifier	meta.id;obs.proposal
proposal_pi		text		Proposal principal investigator	meta.id.PI;obs.proposal
proposal_title		Text		Proposal title	meta.title;obs.proposal
campaign		Text		Name of the observational campaign	meta.id;meta.code
target_description		Text		Original target keywords	meta.note;src
proposal_target_name		Text		target name as in proposal title	meta.note;obs.proposal
target_apparent_radius		Double		Apparent radius of the target	phys.angSize;src
north_pole_position		Double	deg	North pole position angle with respect to celestial north pole	pos.posAng			Group of 5 parameters very specific to APIS. Name is ~ OK, but actually provides the position angle of the planet axis. Use "orientation" for the image.
target_primary_hemisphere		Text		Primary observed hemisphere	meta.id;obs.field
target_secondary_hemisphere		Text		Secondary observed hemisphere	meta.id;obs.field
platesc		Double	arcsec/pixel	spatial resolution per pixel or platescale (on sky only)	instr.scale
orientation		Double		Position angle of image y axis (on sky only)	pos.posAng			Provides the direction of the polar axis in the image, counted clockwise from north.
observer_name		Text		Observer name	obs.observer;meta.main
observer_institute		Text		Observer institute	meta.note;meta.main
observer_id		Integer		Image observer's PVOL numeric identifier	meta.id.PI			Group of 5 from PVOL, OK for general use but UCDs have to be changed in PVOL. meta.pubid in PVOL
observer_code		Text		Image observer's PVOL username	meta.id.PI			meta.pubcode in PVOL
observer_country		Text		Image observer's country of residence	meta.note;obs.observer			meta.pubcountry in PVOL
observer_lon		Double		Observer's approximate longitude	obs.observer;pos.earth.lon			meta.publon in PVOL
observer_lat		Double		Observer's approximate latitude	obs.observer;pos.earth.lat			meta.publat in PVOL
mass		Double	kg	Mass of object	phys.mass			Solar System Objects extension (generic values in catalogues, not observations)
sideral_rotation_period		Double	h	Object rotation rate	time.period.rotation
mean_radius		Double	km		phys.size.radius
equatorial_radius		Double	km		phys.size.radius
polar_radius		Double	km		phys.size.radius
diameter		double	km	Target diameter, or equivalent diameter for binary objects	phys.size.diameter			Used in tnosarecool, not very consistent (use radius?)
semi_major_axis		Double	au		phys.size.smajAxis
inclination		Double		Orbit inclination	src.orbital.inclination
eccentricity		Double		Orbit eccentricity	src.orbital.eccentricity
long_asc		Double	deg	Longitude of ascending node, J2000.0	src.orbital.node
arg_perihel		Double	deg	Argument of Perihelion, J2000.0	src.orbital.periastron
mean_anomaly		Double	deg	Mean anomaly at the epoch	src.orbital.meanAnomaly
dynamical_class		Text		Class of small body, from enumerated list	meta.code.class;src
dynamical_type		Text		Subdivision of the class, from enumerated list	meta.code.class;src
taxonomy_code		Text		Code for target taxonomy	src.class.color			Possible values depend on target type and possibly on service
magnitude		Double	mag	Absolute magnitude. For small bodies, from HG magnitude system	phys.magAbs			Actually depends on service (eg, spectro_planets vs DynAstVO vs tnosarecool). UCD may include mention of the photometric band.
flux		Double	mJy	Target flux	phot.flux.density
albedo		Double		Target albedo	phys.albedo
map_projection		Text		ID from enumerated list	pos.projection			Map extension
map_height		Double	pixel	Map size in px	phys.size
map_width		Double	pixel	Map size in px	phys.size
map_scale		Text		Format TBD	pos.wcs.scale
pixelscale_min		Double	km/pixel	Min pixel size on a surface	instr.scale;stat.min
pixelscale_max		Double	km/pixel	Max pixel size on a surface	instr.scale;stat.max
particle_spectral_type		Text			meta.id;phys.particle			Particle spectroscopy extension, UCD TBD
particle_spectral_range_min		Double			phys.energy;phys.particle;stat.min phys.mass;phys.particle;stat.min
particle_spectral_range_max		Double			phys.energy;phys.particle;stat.max phys.mass;phys.particle;stat.max
particle_spectral_sampling_step_min		Double			spect.resolution;phys.particle;stat.min
particle_spectral_sampling_step_max		Double			spect.resolution;phys.particle;stat.max
particle_spectral_resolution_min		Double			spect.resolution;phys.particle;stat.min
particle_spectral_resolution_max		Double			spect.resolution;phys.particle;stat.max
original_publisher		Text		Refers to the source of the data, e. g., in compilations of experimental data	meta.note;meta.main			Experimental spectroscopy + contributive work extensions
producer_name		Text		Data producer name, especially in compilations of experimental data	meta.note;meta.main
producer_institute		Text		Data producer institute, e. g., in compilations of experimental data	meta.note;meta.main
sample_id		Text		Provides a local ID in an existing catalogue	meta.id;src			In addition to target_name
sample_classification		Text	hash list	Information related to class, sub-class, species…	meta.note;phys.composition			This uses standard names for classes…
sample_desc		Text	can be a hash list	Describes the sample, its origin, and possible preparation	meta.note
data_calibration_desc		Text	can be a hash list	Provides information on post-processing	meta.note			(preferably to a "comment" parameter)
setup_desc		Text	can be a hash list	Describes the experimental setup	meta.note			May include Aperture (size of sample measured), etc
geometry_type		Text	can be a hash list	Type of observation, from enumerated list	meta.note;instr.setup
spectrum_type		Text	can be a hash list?	Type of spectral observation, from enumerated list TBD	meta.note;instr.setup			Alternative to UCD, very detailed
grain_size_min		Double	µm	Min particle size in µm	phys.size;stat.min
grain_size_max		Double	µm	Max particle size in µm	phys.size;stat.max
azimuth_min		Double	deg	Min azimuth angle for illumination	pos.azimuth;stat.min			Check meaning/requirements for <0 values? UCD added in 2018 (instead of pos.azimuthAng requested - OK)
azimuth_max		Double	deg	Max azimuth angle for illumination	pos.azimuth;stat.max			UCD added in 2018
pressure		Double	bar	Ambient pressure	phys.pressure			VOunits says: Pascal. But this is in files
measurement_atmosphere		text		Describes experimental conditions. "vacuum" for measurements under vacuum.	meta.note;phys.pressure
temperature		Double	K	Ambient temperature	phys.temperature
event_type		Text		Type of event from enumerated list (e. g., meteor_shower, fireball, lunar_flash, comet_tail_crossing…)	TBD			Events extension If dataproduct_type = ev UCDs should be provided with the standard
event_status		Text		From enumerated list	TBD
event_cite		Text		From enumerated list	TBD

(1): depending on context (as given by spatial_frame_type). Please comment here: EPN-TAP v2: Current discussion topic

Beware that datatypes apply to the epn_core view, not to the q.rd file where they can be different

Example table for IDs:

File name-type	granule_uid	granule_gid	obs_id
A-Raw	1	native	A
A-Calib	2	calibrated	A
A-geom	3	geometry	A
A-proj	4	projected	A
B-Raw	5	native	B
B-Calib	6	calibrated	B
B-geom	7	geometry	B
B-proj	8	projected	B

Syntax

• multivalued lists = first entry#second entry#…#last entry, or scalar (with no #)
Values separator = #
No quotes around the list

This can be parsed by ADQL/RegTAP function ivo_hashlist_has like this:
select * from vvex.epn_core where 1 = ivo_hashlist_has(lower(target_name),'Venus')

Where the lower function is mandatory to handle values possibly containing upper cases (this is implicit on the 2nd argument)

Beware that only complete elements between separators will be found. The provider has to split the string according to expected searches, e.g.:
Composite Infrared Spectrometer#CIRS
not ~~Composite Infrared Spectrometer (CIRS)~~

Parameters supporting multivalued lists include:
dataproduct_type (only when present in the same file; best avoided when possible)
target_name (for different targets only, but only one target can be described in the granule; use alt_target_name for other names of the same target)
alt_target_name
target_class (in association with target_name)
instrument_host_name (e.g. acronym and full name)
instrument_name (e.g. acronym and full name)
measurement_type (when present in the same file)
processing_level (when present in the same file)
bib_reference

• NULL and special values:
A standard query on a parameter will not return granules with NULL/void value. E.g. target_name LIKE '%toto%' will only select granules with this value (standard ADQL behavior).
NULL/void has to be tested specifically (e.g., when it means "I don't know") using the IS operator (IS is used only to test the NULL value in ADQL):

target_name LIKE '%toto%' OR target_name IS NULL

Syntax IS NULL stands for both strings and numerical parameters (the = operator is accepted in this context only by latest DaCHS servers)

No inf, inf, or NaN value in ADQL? At least Inf/-Inf should be there, as per DALI.

• UCDs: the above table has been reviewed against the UCD documents, including latest discussions (4/2019). Review against PDS4 and IPDA to be performed.

2018 discussions / conclusions have been included here: https://wiki.ivoa.net/twiki/bin/view/IVOA/UCDList1dot42017June2018FebRFM

• *_min vs *_max parameters:

If only one value is available, it must appear in both fields

• Optional parameters: some of these come in sets that are logically related; if one is present, the related ones must be present also (e.g., 3 access_* parameters)

• Granule_gid: any general indication to providers? I.e.: preview, native, calibrated, geometry…
A client should be able to display the values present in a service, TBC (feasible in TOPCAT)

• Reshuffle previous "service parameters":

Mandatory :
publisher - make it mandatory???
add publisher_did as in Obscore? (for DaCHS/registry; provides unique ID of service for this publisher/server), with UCD = meta.ref.uri;meta.curation
Optional - TBC
spatial_coordinate_description (default = none)
spatial_origin (default = body center or SS barycenter? Or observer location)
time_origin (default = observer)
time_scale (default = UTC – no other values allowed in data services? [only in computational services, e.g. ephemeris])
Same values to be used in registry declaration

• Call-back parameters / reference

Currently using service_title (= schema name) + granule_uid.

May use ivoID in the future.

• Other parameters

The most recent extra parameters often have names starting in prefix_*, where prefix identify the scope or context (e.g., spase_, vims_, image_, etc). Seems to be a good practice.

Accref is introduced by the EPN-TAP localfile mixin, but not used. It may be better to hide it entirely in the portal (TBC).

• Parameters introducing error bars/uncertainties

Some parameters providing a scalar value X in the EPN-TAP table may be associated with an error bar in a related parameter. This is currently (4/2019) entered as:

In Basecom: Xerr (to be changed when upgrading to mixin version)
In DynAstVO: X_error
In Exoplanets: X_error_min; X_error_max
In planets: X_uncertainty
TNOsarecool: X_sigma_plus, X_sigma_minus (to be changed?)

The associated UCDs start with stat.error; or stat.error;stat.min; & stat.error;stat.max;

• Support for PDS3 detached labels (proposal)

Solution with datalink seems OK: data files under access_url and detached labels provided under datalink_url in a link table - although no attempt made to read them from the portal yet (use VIR unpublished service to test this).

• Utypes (TBC)

Need to clean up current doc (2.0). Utypes are = DM fields. They are supposedly used to identify the meaning of parameters and help e.g. tools to grab required quantities - This will not work in some areas though, e. g. with spectral tools as they currently use UCD instead of Utype for this purpose (not many tools appear to actually rely on Utype in fact). See discussion here for usage (a bit old?): http://www.ivoa.net/documents/Notes/UTypesUsage/20130213/NOTE-utypes-usage-1.0-20130213.html

To handle this in practice:

Associate each parameter to a specific Utype in EPNCore - all names need to start with the epncore: prefix/namespace.
Then map epncore Utype to other DM (find equivalent parameter, or trace back the original templates of EPNCore parameters - often from ObsCore)
Reuse Utype from other DM each times it makes sense - TBC: the epncore: namespace is still required (even when using Utypes from other DM)
This allows tools to handle EPNCore parameters like existing parameters from other DM, i.e., with no specific implementation
Pb is that small differences in the use of parameters may preclude reusing the same Utype (TBC: does that applies to units also?)
Cross our fingers: known Utype (from other DMs) may be usable in existing tools (e.g. a tool supporting Provenance would grab equivalent info in EPN-TAP services transparently)
Unclear if the use of the namespace makes it more complicated in tools.

Example of V2 with APIS database:

EPNcore Table v2

granule_uid	granule_gid	obs_id	access_url	access_format	thumbnail_url
o5g202x4q_x2d	original_data	o5g202x4q	o5g202x4q_x2d.fits	image/fits	o5g202x4q_x2d_small.jpg
o5g202x4q_x2d_prev	original_data_preview	o5g202x4q	o5g202x4q_x2d.jpg	image/jpg	o5g202x4q_x2d_small.jpg
o5g202x4q_proc	processed_data	o5g202x4q	o5g202x4q_proc.fits	image/fits	o5g202x4q_proc_small.jpg
o5g202x4q_proc_prev	processed_data_preview	o5g202x4q	o5g202x4q_proc.jpg	image/jpg	o5g202x4q_proc_small.jpg
o5g202x4q_cyl	cylindrical_projection	o5g202x4q	o5g202x4q_cyl.jpg	image/jpg	o5g202x4q_cyl_small.jpg
o5g202x4q_pol_n	polar_projection_north	o5g202x4q	o5g202x4q_pol_n.jpg	image/jpg	o5g202x4q_pol_n_small.jpg
o5g202x4q_pol_s	polar_projection_south	o5g202x4q	o5g202x4q_pol_s.jpg	image/jpg	o5g202x4q_pol_s_small.jpg

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