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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)

 

 

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

This was not supported by TAP. Therefore, even constant parameters must be replicated in every line of the epn_core view.

The corresponding parameters may be duplicated in the registry declaration though, to provide a fast description of services.

 

4) Footprints can be provided through s_region

s_region is a parameter in the TAP standard of IVOA, and ADQL allows for powerful query functions such as intersections.

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

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

 

5) Better handling of the evolution of services

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

From our first discussions, the best option may be to use an ISO 8601 string with format "2013-11-17T10:41:00.00+01:00" (we don't want any space in the string) — TBC with ADQL capacities, in particular the support of time zones.

 

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 prevents stupid 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)
  • Planetary 3D modelling run results
  • Exoplanets / planetary systems properties

 

 

+ See notes below the table.

 

Name, v2

Name, v1

Type

Unit

Description

UCD

EPNCore mandatory parameters

 

 

 

 

 

granule_uid

index

Text

 

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

meta.id

granule_gid

_

Text

 

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

meta.id

obs_id

_

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

resource_type

Text

 

Can be dataset or granule

meta.code.class

_ (TBC)

dataset_id

Text

 

Dataset identification & granule reference

meta.id

dataproduct_type

dataproduct_type

Text

 

Organization of the data product, from enumerated list

meta.code.class

target_name

target_name

Text

 

Standard name of target (from a list depending on target type), case sensitive

meta.id;src

target_class

target_class

Text

 

Type of target, from enumerated list

meta.code.class;src

time_min

time_min

Double

d

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

time.start

time_max

time_max

Double

d

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

time.end

time_sampling_step_min

time_sampling_step_min

Double

s

Min time sampling step

time.interval;stat.min

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;stat.min

time_exp_max

time_exp_max

Double

s

Max integration time

time.duration;stat.max

spectral_range_min

spectral_range_min

Double

Hz

Min spectral range (frequency)

em.freq;stat.min

spectral_range_max

spectral_range_max

Double

Hz

Max spectral range (frequency)

em.freq;stat.max

spectral_sampling_step_min

spectral_sampling_step_min

Double

Hz

min spectral sampling step

em.freq.step;stat.min
(not in list)

spectral_sampling_step_max

spectral_sampling_step_max

Double

Hz

Max spectral sampling step

em.freq.step;stat.max
(not in list)

spectral_resolution_min

spectral_resolution_min

Double

Hz

Min spectral resolution

spect.resolution;stat.min

spectral_resolution_max

spectral_resolution_max

Double

Hz

Max spectral resolution

spect.resolution;stat.max

c1min

c1min

Double

(1)

Min of first coordinate

pos;stat.min

c1max

c1max

Double

(1)

Max of first coordinate

pos;stat.max

c2min

c2min

Double

(1)

Min of second coordinate

pos;stat.min

c2max

c2max

Double

(1)

Max of second coordinate

pos;stat.max

c3min

c3min

Double

(1)

Min of third coordinate

pos;stat.min

c3max

c3max

Double

(1)

Max of third coordinate

pos;stat.max

s_region

 

Vector?

 

ObsCore-like footprint, assume spatial_coordinate_description – this one TBC (needs another param for GIS interface?)

instr.fov ?? - doubtful…

phys.angArea;obs (from obsCore)

c1_resol_min

c1_resol_min

Double

(1)

Min resolution in first coordinate

pos.resolution;stat.min
(not in list)

c1_resol_max

c1_resol_max

Double

(1)

Max resolution in first coordinate

pos.resolution;stat.max
(not in list)

c2_resol_min

c2_resol_min

Double

(1)

Min resolution in second coordinate

pos.resolution;stat.min
(not in list)

c2_resol_max

c2_resol_max

Double

(1)

Max resolution in second coordinate

pos.resolution;stat.max
(not in list)

c3_resol_min

c3_resol_min

Double

(1)

Min resolution in third coordinate

pos.resolution;stat.min
(not in list)

c3_resol_max

c3_resol_max

Double

(1)

Max resolution in third coordinate

pos.resolution;stat.max
(not in list)

spatial_frame_type

spatial_frame_type

Text

 

Flavor of coordinate system, defines the nature of coordinates

meta.code.class;pos.frame

incidence_min

incidence_min

Double

 

Min incidence angle (solar zenithal angle)

pos.posang;stat.min 

incidence_max

incidence_max

Double

 

Max incidence angle (solar zenithal angle)

pos.posang;stat.max 

emergence_min

emergence_min

Double

 

Min emergence angle

pos.posang;stat.min 

emergence_max

emergence_max

Double

 

Max emergence angle

pos.posang;stat.max

phase_min

phase_min

Double

 

Min phase angle

pos.phaseang;stat.min

phase_max

phase_max

Text

 

Max incidence angle

pos.phaseang;stat.max

instrument_host_name

instrument_host_name

Text

 

Standard name of the observatory or spacecraft

meta.id;instr.obsty

instrument_name

instrument_name

Text

 

Standard name of instrument

meta.id;instr

measurement_type

measurement_type

Text

 

UCD(s) defining the data

meta.ucd

creation_date

 

ISO-8601 String

 

Date of first entry of this granule

time.creation

modification_date

 

ISO-8601 String

 

Date of last modification (used to handle mirroring)

time.update

release_date

 

ISO-8601 String

 

Start of public access period

time.release

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

label_url_Text URL of possible detached label - if not empty, will be handled by the client before samping it to tools or downloading meta.ref.url;meta.file ???

access_format

access_format

Text

 

File format type (mime type in lowercases)

meta.code.mime

access_estsize

access_estsize

Integer

kB

Estimate file size in kB

phys.size;meta.file
(TBC)

access_md5Text MD5 Hash for the file when available (real file) 

_
replaced by another granule group

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)

thumbnail_url

_

Text

 

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

meta.ref.url;meta.file

file_name

file_name

Text

 

Name of the data file only, case sensitive

meta.id;meta.file

species

species

Text

 

Identifies a chemical species, case sensitive

meta.id;phys.atmol

target_region

target_region

Text

 

Type of region of interest

meta.id;class

feature_name

element_name

Text

 

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

meta.id;pos

bib_reference

reference

Text

 

Bibcode, doi, or other biblio id, URL…

meta.bib

ra

ra

Double

 

Right ascension

pos.eq.ra;meta.main

dec

dec

Double

 

Declination

pos.eq.dec;meta.main

solar_longitude_min

solar_longitude

Double

 

Min Solar longitude Ls (location on orbit / season)

pos.posangle (TBC)

solar_longitude_max

solar_longitude

Double

 

Max Solar longitude Ls (location on orbit / season)

pos.posangle (TBC)

local_time_min

local_time_min

Double

h

Local time at observed region

time.phase;stat.min?

local_time_max

local_time_max

Double

h

Local time at observed region

time.phase;stat.max?

target_distance_min

target_distance (no min/max)

Double

km

Observer-target distance

pos.distance;stat.min

target_distance_max 

Double

kmObserver-target distancepos.distance;stat.max

target_time_min

_

Double

d

Observing time in target frame

time.start ??

target_time_max

_

Double

d

— TBC if we want both

time.end ??

particle_spectral_type

particle_spectral_type

Text

 

 

 

particle_spectral_range_min

particle_spectral_range_min

Double

 

 

 

particle_spectral_range_max

particle_spectral_range_max

Double

 

 

 

particle_spectral_sampling_step_min

particle_spectral_sampling_step_min

Double

 

 

 

particle_spectral_sampling_step_max

particle_spectral_sampling_step_max

Double

 

 

 

particle_spectral_resolution_min

particle_spectral_resolution_min

Double

 

 

spect.resolution;stat.min

particle_spectral_resolution_max

particle_spectral_resolution_max

Double

 

 

spect.resolution;stat.max

Relative to service / Table header
(mandatory or not?)

 

 

 

 

 

processing_level

processing_level

Integer

 

CODMAC calibration level in v1
To be replaced by PDS4 values in v2?

meta.code;obs.calib

publisher

publisher

Text

 

Resource publisher

meta.name

service_title

service_title
(was initially "title")

Text

 

Title of resource

meta.title

spatial_coordinate_description

spatial_coordinate_description

Text

 

?

?

spatial_origin

spatial_origin

Text

 

Defines the frame origin

meta.ref;pos.frame

time_origin

time_origin

Text

 

Defines where the time is measured

?

time_scale

?

Text

 

Always UTC in data services (may be relaxed in computational services such as ephemeris)

time.scale

 

(1): depending on context (as given by spatial_frame_type)




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


• string delimiter for enumerated lists = #first entry#second entry#…#last entry#
TBC with PDS, exoplanets, NSSDC…  (requires a character which never appears in target names, etc)


• 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.
For strings: not needed? (i.e. NULL/void is OK?)

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

• Processing levels: to be reviewed against PDS4 (again)

• 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 from a service, TBC


• Reshuffle previous "service parameters":

  • Mandatory :
    processing_level -mandatory
    publisher -mandatory
    service_title –mandatory
  • Optional - TBC
    spatial_coordinate_description  (implicitly body-fixed or J2000)
    spatial_origin  (implicitly body center or SS barycenter? Or observer location)
    time_origin  (implicitly: observer)
    time_scale (implicitly : 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" (no other way: 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 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. Can be extended to other formats.

 

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.fitsfitso5g202x4q_x2d_small.jpg
o5g202x4q_x2d_prevoriginal_data_previewo5g202x4qo5g202x4q_x2d.jpgjpgo5g202x4q_x2d_small.jpg
o5g202x4q_procprocessed_datao5g202x4qo5g202x4q_proc.fitsfitso5g202x4q_proc_small.jpg
o5g202x4q_proc_prevprocessed_data_previewo5g202x4qo5g202x4q_proc.jpgjpgo5g202x4q_proc_small.jpg
o5g202x4q_cylcylindrical_projectiono5g202x4q o5g202x4q_cyl.jpg jpgo5g202x4q_cyl_small.jpg
o5g202x4q_pol_npolar_projection_northo5g202x4q o5g202x4q_pol_n.jpg jpgo5g202x4q_pol_n_small.jpg
o5g202x4q_pol_spolar_projection_southo5g202x4q o5g202x4q_pol_s.jpg jpgo5g202x4q_pol_s_small.jpg
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