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List of EPN-TAP parameters
v2, 3/8/2015 (SE)
v3, 29/8/2015 (SE, integrating comments by PLS and BC)
v4, 7/9/2015 (SE, integrating comments by PLS)
v5, 7/10/2015 (SE, integrating comments by PLS: time_scale UCD)
v6, 7/11/2015 (SE, integrating comments by PLS/BC)
v7, 14/12/2015 (SE, added point 8, clarification of an older idea)
v8, 24/12/2015 (SE, review/integration of comments/corrections)
v9, 5-7/01/2016 (SE/BC, including comments from Chiara Marmo and Michel Gangloff)
v10, 21/02/2016 (SE, from model implementation of IKS)
v11, 11/5/2016 (SE, systematic comparison with ObsCore again & variations for spatial coordinates)

 

 

New in v2

  • The "laundry list" format makes services easier to design and to query
  • Allows grouping of results from several services at once
  • Supports multispacecraft observations
  • Speeds up mirroring of services (support for partial updates)
  • Better support of footprints, and better interface with GIS

 

Main evolution relative to v1

1) The previous notion of dataset is deprecated

This was complex to handle in the database, and in general not relevant for the services.

 

2) Grouping of products is rationalized in version 2

A granule is still a record/line in the epn_core view database, and corresponds to the smallest data unit described by the service.

A "product" is typically a data file, or a service output, that can be reached through a URL

In version 2 both concepts coincide, while in v1 the same granule could be composed of several products related to the same initial data (an "observation")

 

In EPN-TAP v2, granules are referenced by 3 parameters:

  • granule_uid provides a unique ID for the granule in the service, ie for each line in the epn_core view. It is equivalent to the previous index parameter (index is a reserved word in many database languages and should not have been used in the first place)
  • granule_gid is related to a type of product: it is identical for all granules containing the same type of information for different observations (e.g., calibrated files). An explicit string is recommanded in this field, with suggested standard values (e.g., preview/native/calibrated/geometry/projection…).
  • obs_id is related to an observation: it is identical for all granules related to the same observation, containing different type of data (e.g.: raw and calibrated data, associated geometry, etc). In many EPN-TAP v1 services, such products were described together on the same line with a unique index parameter.

These 3 parameters can be arbitrary alphanumeric strings — see example application to APIS service below.

 

In practice, different products related to the same observation are no longer described together on a single line of the epn_core view, but on successive lines associated by the same obs_id, each with a different granule_gid (and a specific granule_uid, see Table 2 below).

Each line in the epn_core view must describe only one product (plus a thumbnail wherever relevant). The notion of "main product" (which was more or less explicit in v1) is therefore deprecated, and the epn_core view in v2 includes more lines than in v1. Although less compact that the previous table presentation, this list presentation is much more efficient for machine-handling, and easier to design.

 

3) The notion of table/service parameters is deprecated

Such parameters were not directly accessible by TAP. In v2, constant parameters must be replicated in every line of the epn_core view.

Such parameters may be duplicated in the registry declaration though, so as to provide a fast description of services.

 

4) Footprints can be provided through s_region

s_region is a parameter in the ObsCore standard of IVOA, and ADQL allows for powerful query functions such as intersections. s_region introduces an STC-S string providing description of the observed area on a sphere.

We have to study a possible extension of its use from regions of the sky to body-related coordinates (either on ellipsoids or 3D shape models) .

The use in the context of GIS also has to be studied.

 

5) Better support of evolving services

creation_date and modification_date are now mandatory parameters for every granule. The latter is intended to optimize mirroring of services, by identifying the granules to be updated/copied.

These parameters must be provided as ISO 8601 strings with format "2013-11-17T10:41:00.00+01:00" (with no space) where the indication of time zone is mandatory. The associated data type must be "date". ADQL supports this format and filtering using time zone is possible.

 

6) Support of coordinated observations

The target_time parameter now provides observation time in the reference frame of the target. This is intended to facilitate the cross-correlation of observations from different locations, e.g., telescopic observations in support of space missions, or multi-spacecraft campaigns.

 

7) Axes ranges

All parameters defining a range are now introduced with a min and max value.

All floating point parameters are now in double precision to prevent errors.

 

8) 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)
  • Orbital/rotational parameters and physical properties of Solar System bodies (TBC, but requested by some)
  • Results of planetary 3D modelling run
  • Exoplanets / planetary systems properties
  • Bibliographic entries? May be manageable otherwise, through bibcode / doi interpretation

 

9) 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.


Name, v2

Must be filled?

Name, v1

SQL type

Unit / Format / Range

Description

UCD

Please comment!
 

UCD in Obscore 1.1 (30/3/2016 version)Comments

EPNCore mandatory parameters
(Must be present, possibly empty)

 

 

 

 

 

Current value
current but dubious or undefined
possible alternative

— ? : closest sense

_ : N/A

 

granule_uid

Y

index

Text

 

Internal table row index
Unique ID in data service, also in v2. Can be alphanum.

meta.id

  meta.id;meta.dataset

meta.id 

granule_gid

Y


Text

 

Common to granules of same type (e.g. same map projection, or geometry data products). Can be alphanum.

meta.id

meta.id 

obs_id

Y


Text

 

Associates granules derived from the same data (e.g. various representations / processing levels). Can be alphanum., may be the ID of original observation.

meta.id

  meta.id;obs

meta.id 


 

resource_type

Text

 

Can be dataset or granule

(meta.code.class)

_ 


 

dataset_id

Text

 

Dataset identification & granule reference

(meta.id)


_ 

dataproduct_type

Y

dataproduct_type

Text

 

Organization of the data product, from enumerated list

meta.code.class

meta.id 

target_name

Y

target_name

Text

 

Standard IAU name of target (from a list related to target class), case sensitive

meta.id;src

meta.id;src 

target_class

Y

target_class

Text

 

Type of target, from enumerated list

meta.code.class;src

 src.class

src.class 

time_min

 

time_min

Double

d (date as JD)

Acquisition start time (in JD). UTC measured at time_origin location (default is observer's frame)

time.start

 time.start;obs

time.start;obs.exposure 

time_max

 

time_max

Double

d (date as JD)

Acquisition stop time (in JD). UTC measured at time_origin location (default is observer's frame)

time.end

 time.end;obs

time.end;obs.exposure 

time_sampling_step_min

 

time_sampling_step_min

Double

s

Min time sampling step

time.interval;stat.min

time.resolution — ? 

time_sampling_step_max

 

time_sampling_step_max

Double

s

Max time sampling step

time.interval;stat.max

  

time_exp_min

 

time_exp_min

Double

s

Min integration time

time.duration;obs.exposure;stat.min

time.duration;obs.exposure 

time_exp_max

 

time_exp_max

Double

s

Max integration time

time.duration;obs.exposure;stat.max

  

spectral_range_min

 

spectral_range_min

Double

Hz

Min spectral range (frequency)

em.freq;stat.min

em.wl;stat.min

(always as wl)
Always as freq

spectral_range_max

 

spectral_range_max

Double

Hz

Max spectral range (frequency)

em.freq;stat.max

em.wl;stat.max 

spectral_sampling_step_min

 

spectral_sampling_step_min

Double

Hz

Min spectral sampling step

em.freq.step;stat.min

meta.number 

spectral_sampling_step_max

 

spectral_sampling_step_max

Double

Hz

Max spectral sampling step

em.freq.step;stat.max

meta.number 

spectral_resolution_min

 

spectral_resolution_min

Double

Hz

Min spectral resolution

spect.resolution;stat.min

spect.resolution 

spectral_resolution_max

 

spectral_resolution_max

Double

Hz

Max spectral resolution

spect.resolution;stat.max

  

c1min

 

c1min

Double

(1)

Longitude from 0. to 359.9999

RA from 0. to 23.9999

Min of first coordinate

pos;stat.min

pos.angDistance;stat.min
or
pos.bodyrc.lon;stat.min — for spherical & cylindrical ?

pos.eq.ra for celestial 

pos.bodyrc.lon for body

pos.cartesian.x for cartesian

pos.healpix for healpix (with 2 coordinates ?)

pos.eq.ra 

c1max

 

c1max

Double

(1)

Max of first coordinate

pos;stat.max

  

c2min

 

c2min

Double

(1)

Min of second coordinate

pos;stat.min

pos.angDistance;stat.min
or
pos.bodyrc.lat;stat.min — for spherical & cylindrical ? (needs colat ?)

pos.eq.dec for celestial 

pos.bodyrc.lat for body

pos.cartesian.y for cartesian

pos.eq.dec 

c2max

 

c2max

Double

(1)

Max of second coordinate

pos;stat.max

  

c3min

 

c3min

Double

(1)

Min of third coordinate

pos;stat.min

pos.distance;pos.bodyrc
or
pos.bodyrc.alt;stat.min — for spherical & cylindrical ?

pos.distance for celestial 

pos.bodyrc.alt for body ? (from surface only, implicitly from reference level)
or
pos.distance;pos.bodyrc for body (from center)?

pos.cartesian.z for cartesian

  

c3max

 

c3max

Double

(1)

Max of third coordinate

pos;stat.max

  

s_region

 

 

Text

(STC-S String)

ObsCore-like footprint, assume spatial_coordinate_description

instr.fov

  phys.outline;obs.field

phys.outline;obs.field

Current UCD doubtful.
obsCore value recently updated (was phys.angArea;obs)

Do we need another param for GIS interface?

c1_resol_min

 

c1_resol_min

Double

(1)

Min resolution in first coordinate

pos.resolution;stat.min

 pos.angResolution;stat.min
if angular

pos.angResolution;stat.min(UCD is deprecated, but needed!)

c1_resol_max

 

c1_resol_max

Double

(1)

Max resolution in first coordinate

pos.resolution;stat.max

pos.angResolution;stat.max(UCD is deprecated, but needed!)

c2_resol_min

 

c2_resol_min

Double

(1)

Min resolution in second coordinate

pos.resolution;stat.min
 pos.angResolution;stat.min
if angular

 (UCD is deprecated, but needed!)

c2_resol_max

 

c2_resol_max

Double

(1)

Max resolution in second coordinate

pos.resolution;stat.max

 (UCD is deprecated, but needed!)

c3_resol_min

 

c3_resol_min

Double

(1)

Min resolution in third coordinate

pos.resolution;stat.min
 pos.angResolution;stat.min
if angular
(spherical only)

 (UCD is deprecated, but needed!)

c3_resol_max

 

c3_resol_max

Double

(1)

Max resolution in third coordinate

pos.resolution;stat.max

 (UCD is deprecated, but needed!)

spatial_frame_type

 

spatial_frame_type

Text

(1)

Flavor of coordinate system, defines the nature of coordinates. From enumerated list

meta.code.class;pos.frame

_ 

incidence_min

 

incidence_min

Double

deg

Min incidence angle (solar zenithal angle)

pos.posAng;stat.min 

 pos.incidenceAng;stat.min

_ 

incidence_max

 

incidence_max

Double

deg

Max incidence angle (solar zenithal angle)

pos.posAng;stat.max 

 pos.incidenceAng;stat.max

_ 

emergence_min

 

emergence_min

Double

deg

Min emergence angle

pos.posAng;stat.min 

 pos.emergenceAng;stat.min

_ 

emergence_max

 

emergence_max

Double

deg

Max emergence angle

pos.posAng;stat.max

 pos.emergenceAng;stat.max

_ 

phase_min

 

phase_min

Double

deg

Min phase angle

pos.phaseAng;stat.min

  

phase_max

 

phase_max

Double

deg

Max phase angle

pos.phaseAng;stat.max

  

instrument_host_name

 

instrument_host_name

Text

 

Standard name of the observatory or spacecraft

meta.id;instr.obsty

meta.id;instr.tel 

instrument_name

 

instrument_name

Text

 

Standard name of instrument

meta.id;instr

meta.id;instr 

measurement_type

 

measurement_type

Text

 

UCD(s) defining the data

meta.ucd

meta.ucd 

processing_level

 

processing_level

Integer

 

CODMAC calibration level in v1

meta.code;obs.calib

   meta.calibLevel

meta.code;obs.calib

To be replaced by PDS4 values in v2?

creation_date

Y Date

(ISO-8601 String)

Date of first entry of this granule

time.creation

time;meta.dataset 

modification_date

Y Date(ISO-8601 String)

Date of last modification (used to handle mirroring)

time.update

 time.process

  

release_date

Y Date

(ISO-8601 String)

Start of public access period

time.release

time.release 

service_title

Y

service_title
(still "title" in many v1 services)

Text

 

Title of resource (an acronym really, will be used to handle multiservice results)

meta.title

  

Optional parameters

 

 

 

 

 

 

  

access_url

 

access_url

Text

 

URL of the data file, case sensitive. If present, next 2 parameters must be present.

meta.ref.url;meta.file

meta.ref.urlUse this to link data!

access_format

 

access_format

Text

 (mime type in lowercase)

File format type  

meta.code.mime

meta.code.mime 

access_estsize

 

access_estsize

Integer

kbyte

Estimate file size in kbyte (with this spelling)

phys.size;meta.file

phys.size;meta.file 

data_access_url

(best avoided and replaced by datalink in access_url, TBC)

  Text If access_format indicates a detached label, this parameter is mandatory and points to the corresponding data file - both will be handled by the client before samping it to tools or downloading- TBC
meta.ref.url;meta.file
 Must be filled? being questioned!
access_md5  Text MD5 Hash for the file when available (real file) meta.checksum;meta.file  

 

 

preview_url

Integer

 

URL of a preview image (std format with adequate resolution for user's purpose)

(meta.ref.url;meta.file)

 replaced by another granule group

 

 

native_access_url

Text

 

URL of the data file in native form, case sensitive

(meta.ref.url;meta.file)

 replaced by another granule group

 

 

native_access_format

Text

 

File format type in native form

(meta.id;class)
(or meta.code.mime if we use MIME type)

 replaced by another granule group

thumbnail_url

 


Text

 

URL of a thumbnail image with predefined size (png ~200 pix, for use in a client only)

meta.ref.url;meta.file

 meta.ref.url;meta.preview 

  

file_name

 

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?

species

 

species

Text

 

Identifies a chemical species, case sensitive

meta.id;phys.atmol

  
alt_target_name  Text Provides alternative target name if more common (e.g. comets)meta.id;src  

target_region

 

target_region

Text

 

Type of region of interest

meta.id;class

  obs.field

  

feature_name

 

element_name

Text

 

Secondary name
(can be standard name of region of interest)

meta.id;pos

  obs.field 

 

bib_reference

 

reference

Text

 

Bibcode preferred if available, doi, or other biblio id, URL…

meta.bib

 meta.bib.bibcode (if bibcode)

meta.bib.bibcode

(always as bibcode)

 

ra

 

ra

Double

deg or h:m:s?

Right ascension (not hour angle…)

pos.eq.ra;meta.main

  

dec

 

dec

Double

deg

Declination

pos.eq.dec;meta.main

  

solar_longitude_min

 

solar_longitude

Double

deg

Min Solar longitude Ls (location on orbit / season)

pos.posangle

pos.posAng;pos.heliocentric;stat.min
or

pos.angDistance;pos.heliocentric;stat.min

  

solar_longitude_max

 

solar_longitude

Double

deg

Max Solar longitude Ls (location on orbit / season)

pos.posangle

pos.posAng;pos.heliocentric;stat.max
or

pos.angDistance;pos.heliocentric;stat.max

  

local_time_min

 

local_time_min

Double

h

Local time at observed region

time.phase;stat.min

  time.period.rotation;time.phase;stat.min

  

local_time_max

 

local_time_max

Double

h

Local time at observed region

time.phase;stat.max

 time.period.rotation;time.phase;stat.max

  

target_distance_min

 

target_distance

Double

km

Observer-target distance

pos.distance;stat.min

 was target_distance without min/max in v1
target_distance_max  

Double

kmObserver-target distancepos.distance;stat.max  

target_time_min

 


Double

d

Observing time in target frame (simplest way to look for coordinated observations)

time.start

 ??

target_time_max

 


Double

d


time.end

 ??

particle_spectral_type

 

particle_spectral_type

Text

 

 

Use phys.particle?

  

particle_spectral_range_min

 

particle_spectral_range_min

Double

 

 

Use phys.particle?

  

particle_spectral_range_max

 

particle_spectral_range_max

Double

 

 

Use phys.particle?

  

particle_spectral_sampling_step_min

 

particle_spectral_sampling_step_min

Double

 

 

Use phys.particle?

  

particle_spectral_sampling_step_max

 

particle_spectral_sampling_step_max

Double

 

 

Use phys.particle?

  

particle_spectral_resolution_min

 

particle_spectral_resolution_min

Double

 

 

spect.resolution;stat.min

Use phys.particle?

  

particle_spectral_resolution_max

 

particle_spectral_resolution_max

Double

 

 

spect.resolution;stat.max

Use phys.particle?

  

More optional (TBC)

 

were "Relative to service" (Table header)

 

 

 

 

  

publisher

 

publisher

Text

 

Resource publisher

meta.name

 meta.curation

meta.ref.url;meta.curation — ? 

spatial_coordinate_description

 

spatial_coordinate_description

Text

 

ID of specific coordinate system and version

meta.code.class;pos.frame

 still TBD. Discussion in progress here: EPN-TAP v2: Current discussion topic

spatial_origin

 

spatial_origin

Text

 

Defines the frame origin

meta.ref;pos.frame

  

time_origin

 

time_origin

Text

 

Defines where the time is measured (e. g., ground vs spacecraft) [target_time is of course always on target].

meta.ref;time.scale
or
pos;time.scale

 TBC

time_scale

 

 

Text

 

Always UTC in data services (may be relaxed in computational services such as ephemeris) - from enumerated list

time.scale

  

 

(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:

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

 

Other modifications, to be reviewed


mutlivalued lists = first entry#second entry#…#last entry, or scalar (with no #)
string delimiter = #

Tests show that this can be parsed by ADQL/RegTAP function ivo_hashlist_has, looks like the most flexible solution:
  select * from vvex.epn_core where 1 = ivo_hashlist_has(lower(target_name),'Venus')

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


Defaut values:
NULL/void: will never return an answer to a query using this parameter (TBC, seems ADQL-related. To be corrected if it is a limitation of the client)
For float / double : -inf for *_min +inf for *_max – still TBC (NaN won't do). To be tested on a real case.
Not needed for strings? (i.e. NULL/void is OK?)
Default behavior looks OK in fact. If we need to preserve the NULL values on queried parameters (ie, when NULL is considered as "I don't know"), this can be done with a OR param = NULL (on option in the client? This is feasible manually on TapHandle)

 

UCDs: to be reviewed against PDS4 and IPDA, and completed

Processing levels: to be reviewed against PDS4 (again- mostly related to geometry, considered as derived in PDS4)

min vs max:
if only one value available, it must appear in both fields

• Optional parameters: they 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

• Reshuffle previous "service parameters":

  • Mandatory :
    processing_level -mandatory
    service_title –mandatory
    publisher -mandatory???
  • Optional - TBC
    spatial_coordinate_description  (default = body-fixed or J2000)
    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 

 

Support for PDS3 detached labels (proposal)

access_format = "PDS3label" (it has to be here: we need to know that there is a detached label)
then access_url points to the label, and data_access_url points to the file (param is mandatory in this case - although the data file name is in the label, it can be in another directory)
A script can then recover both files and do something with them. This mechanism can be extended to other formats with detached labels (ENVI…).
Check solution with datalink first

 

Example of V1 to V2 conversion with APIS database:

EPNcore Table v1

(was not really compliant…)

indexresource_typedataset_idaccess_urlaccess_formatpreview_urlnative_access_urlnative_access_format
23801granuleoriginal_datao5g202x4q_x2d.jpgjpgo5g202x4q_x2d_small.jpg

o5g202x4q_x2d.fits

fits
23802granuleprocessed_datao5g202x4q_proc.jpgjpgo5g202x4q_proc_small.jpgo5g202x4q_proc.fitsfits
23803granulecylindric_projo5g202x4q_cyl.jpgjpgo5g202x4q_cyl_small.jpg  
23804granulepolar_proj_northo5g202x4q_pol_n.jpgjpgo5g202x4q_pol_n_small.jpg  
23805granulepolar_proj_southo5g202x4q_pol_s.jpgjpgo5g202x4q_pol_s_small.jpg  

EPNcore Table v2

granule_uidgranule_gidobs_idaccess_urlaccess_formatthumbnail_url
o5g202x4q_x2doriginal_datao5g202x4qo5g202x4q_x2d.fitsimage/fitso5g202x4q_x2d_small.jpg
o5g202x4q_x2d_prevoriginal_data_previewo5g202x4qo5g202x4q_x2d.jpgimage/jpgo5g202x4q_x2d_small.jpg
o5g202x4q_procprocessed_datao5g202x4qo5g202x4q_proc.fitsimage/fitso5g202x4q_proc_small.jpg
o5g202x4q_proc_prevprocessed_data_previewo5g202x4qo5g202x4q_proc.jpgimage/jpgo5g202x4q_proc_small.jpg
o5g202x4q_cylcylindrical_projectiono5g202x4q o5g202x4q_cyl.jpgimage/jpgo5g202x4q_cyl_small.jpg
o5g202x4q_pol_npolar_projection_northo5g202x4q o5g202x4q_pol_n.jpgimage/jpgo5g202x4q_pol_n_small.jpg
o5g202x4q_pol_spolar_projection_southo5g202x4q o5g202x4q_pol_s.jpgimage/jpgo5g202x4q_pol_s_small.jpg
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