Attending: Ward Fisher (WF), Josh Moore (JM), Sanket Verma (SV), Jonathan Striebel (JS), Jeremy Maitin-Shepard (JMS), Ryan Abernathey (RA)


During the meeting, SV provided an update on the current voting status for ZEP0001, while WF plans to vote soon with the assistance of colleagues at Unidata. RA suggested that we should be open to changes in the living document, i.e. V3 Spec and not adhere strictly to the by-laws. JS recommended having a list of contributors on the ZEP0001 page. SV also discussed pending tasks on the ZEP0001 project board before finalising the spec. JMS briefly discussed Mark’s comments on the sharding PR, and the meeting concluded with an impromptu discussion about organising a Zarr conference.


  • ZEP0001 review
    • Ends in 2 days on 5/6 @ 23:59
    • 2 votes so far
      • Constantine - ABSTAIN
      • Jeremy - YES
    • 8 votes pending - (if we leave zarr-python out then 7)

Meeting Minutes:

  • SV: summary on votes so far (as above)
  • WF: Working with the colleagues @ Unidata - will be voting on the V3 Spec soon!
  • RA: wouldn’t stick hard-and-fast to the by-laws if they need
    • JS: Mostly giving people a point in time for veto. It’s a living document.
    • WF: comparing to markdown, might be good to have this process
    • SV: @Ward - Is there a PR you’re looking to submit for ZEP1 review?
    • WF: User attributes for the metadata field - a bit certainity in must_understand flag and user defined attributes - we can have arbitary tags in user attributes specifying it doesn’t require must_understand flag - will prepare a PR for the same
    • JMS: think of the review as an intent to implement
    • JM: agree, looking forward to using this to garner motivation
    • JS: looking forward to a retrospective; smaller changes.
    • RA: specturm of processes; OGC is the most heavy-handed; STAC is most agile (what’s their trick? everything has an implementation)
    • JM: STAC still needs to do the major upgrade to V2 - something I’m looking forward to
  • must_understand flag
    • JMS: Still not clear on Dennis’ objection
    • WF: (for Dennis) worried about future changes painting us into a corner - good to keep Dennis in loop and listen to his concerns
    • JS: Point where you can see both the sides - it’s not a deal breaker for the V3 Spec
    • RA: Any downside for making must_understand flag a required attribute for an extension? - Seems lightweight and can satisfy Dennis
    • JS: To rephrase JMS’s point - “You can do this but then it’s not possible to have non-object entries in the config again.”
    • JMS: We haven’t clarified in codecs the presence of unknown attributes in codecs!
  • JS: Would be good to have a list of contributors for the ZEP1
    • SV: Will complete it before we finalise ZEP1
    • JM: Would be good to put Zarr Spec on Zenodo as well!
  • SV: State of the ZEP1 project board
    • 2 issues in meta and 1 under discussion
    • JS: We can ignore the one under discussion - RA can take care of the OGC one
    • RA: We can update the community standard we already have with OGC
    • JS: Not super happy with how we do the Spec work atm - see #179 - we need to address this once V3 gets finalised
    • SV: What does updating V3 at OGC means? Does it supersedes V2 or V3 gets published at a new URL alongside V2?
    • All: Don’t know! RA can take care of it.
  • RA: geozarr has become a comparison of geo/weather specs
    • but will remain a convention
    • JM: love to hear more. Maybe we can have a Zarr conventions convention ;)
    • RA: all spatial/temporal. with infinite time, would be great to work together.
  • JMS: Discussion on comments by Mark on Sharding PR
    • Would be a good thing to add checksum of the index not the individual chunks (data) - will add 4 extra bytes to the index - JMS favour this!
    • JS: Would be good to ask Norman - but I also favour the idea
  • Impromptu discussion on organsing a Zarr Conference
    • JS: Really good idea! We should have it
    • JMS: In-person has more values
    • JS: Would be good co-locate with other conferences
    • JM: From my experience it was difficult to get together folks from different fields - maybe we can look for hosts like Janelia, NASA etc.
    • JM: Thermo fisher is also looking into Zarr