ObsCore 1.1: Erratum 2

Author: DM WG

Date last changed: 2018-11-18

Date accepted:

Rationale

This erratum corrects a few issues noted in the ObsCore-1.1 document . Since most are small typo level items, it we include multiple items in one erratum.

  1. Implementation feedback from Marco Molinaro, see http://mail.ivoa.net/pipermail/dm/2017-August/005604.html:
cite:
>> 1 - pol_states This field is listed as mandatory in 3.2 (Table 1, page 21) but then, Appendix B page 42, in Table 5 the MANdatory column says NO. After that, Table 6 on page 57 lists pol_states again among the mandatory fields. This looks like simply a typo.

>> 2 - t_refpos This field is listed in Table 5 (Appendix B) page 41 as an optional one, but has no other entry in the specification, e.g. it has no entry in Table 7 (Appendix C.2) so that no Utype or UCD is defined for it. This one looks like a simple forgetfulness.
>> 3 - units for strings Table 5 (pagg. 40-43) reports units for the various fields. However it defines string-type fields to be unitless except for s_region (no value is reported) and proposal_id (which is set as unit=string).

Author answers about t_refpos :

  • as we are considering Time series to be handled by ObsCore for discovery, this reference for the time system has to be re worked. Feedback from the dm list is welcome for this.
  • It seems this is a placeholder for future expansion of ObsCore, it seems appropriate to remove this item from the Table 5, and restore it when the full specification can be provided in an update to the REC.
  • Meanwhile, t_refpos will be removed from the optional parameter

Erratum Content

pol_states

Original Wording
  • Table 1, page 21: pol_states is mandatory
  • Appendix B page 42, in Table 5: MANdatory=no for pol_states
  • Table 6 on page 57: pol_states is mandatory
  • This field is listed as mandatory in 3.2 (Table 1, page 21) but then, Appendix B page 42, in Table 5 the MANdatory column says NO. After that, Table 6 on page 57 lists pol_states again among the mandatory fields. This looks like simply a typo.
New Wording
  • Appendix B: Table 5 on page 42: pol_states is MAN=YES

t_refpos

Original Wording
  • t_refpos mentionned in Table 5 (Appendix B) page 41 as an optional.
New Wording
  • t_refpos removed from Table 5 (Appendix B)

units for strings

Original Wording
  • Table 5 page 40: s_region: unit = "" .
  • Table 5 page 43: proposal_id : unit = "string".
New Wording
  • Table 5 page 40: s_region: unit = "unitless" .
  • Table 5 page 43: proposal_id : unit = "unitless".

missing facility_name

Original Wording
  • facility_name missing in table 5
New Wording
  • facility_name added to table 5 added as mandatory field

Inconsistency in 'principal' settings

Original Wording
  • The following fields, all declared as optional (MAN = NO) in table 5 page 40 and ‘principal’ is set to 1 in TABLE 6.
    • dataproduct_subtype
    • target_class
    • obs_creation_date
    • obs_creation_name
    • obs_title
    • publisher_id
    • obs_release_date
    • s_ucd
    • s_unit
    • s_resolution_min
    • s_resolution_max
    • s_pixel_scale
    • s_calib_status
    • em_ucd
    • em_unit
    • em_res_power_min

New Wording
  • No change in tables 5 and 6
  • Page 55: The definition of the principal column has been updated. Its is not equivalent to mandatory status of the field. All mandatory fields are principal but some optional fields may be considered ‘principal'.

Impact Assessment

  • Implementations which follow the ObsCore specification for these UDS are compliant with the model spec, but produce a validation error by taplint which validates the UCD value against the UCD specification.
  • Clients using t_refpos are non longer compliant with the spec. This column must be now considered as an Obscore extension.
  • Implementation not using pol_states must add this column to be compliant

Notes

  1. The proposed changes are in the errata proposed document attached here REC-ObsCore-v1.1-20181130_errata.pdf
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Topic revision: r6 - 2019-05-10 - MireilleLouys
 
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