2022 08 05 Meeting Minutes - OpenNavigationSurface/crs_specification GitHub Wiki

2022-05-05 0800 ET on Google Meet

Attendees: Weston, Andre, Eric, Chris, Glen

  1. Action Items from previous discussion

    1.1 Make repo, add notes, links, and examples (xml, kinds of transformations NOAA wants to store as part of CRS) - Done

    1.2 Confirm BAG lib operation with the CRS fields as they exist - In work

  2. BoundCRS as a solution - example in repo.

    2.1 Abridged Transformation - Appears to "work" the the example provided by NOAA/OCS for creating a BoundCRS. Making this operational has not been tested yet, but at least contains the components to carry the desired information.

    2.2 The example provided is based on a PROJ string. Should this be converted to a concatenated coordinate operation for generality?

    2.3 Would a BoundCRS be better if not compound? There will be a need to support more sophisticated 4D transformations. Just focusing on the current case does not address larger issue of supporting transformations. Example that would fit in the vertical part of the BAG xml created in repo examples.

    2.4 Should we recommend EPSG transformations operations to facilitate use? This helps with interoperability, but does not work with PROJ strings.

  3. DerivedCRS as a solution - PROJ mailing list thread "Derived Vertical CRS"

    3.1 Based on our understanding of a DerivedCRS, this is for making different versions of the same datums and so is not applicable for the case provided (see Andre's response on PROJ mailing list).

  4. If CRS is compound (such as the BoundCRS example) or 3D, the first CRS codespace in the XML can be used and the second will be ignored.

  5. XML provides for a code space to assign a version number. This could help with future backward compatibility.

  6. Action items for next meeting

    6.1 Set next meeting (September) - Glen

    6.2 Provide examples of various solutions and approaches for next discussion - All should have the ability to commit to the repo

    6.3 Complete confirmation of CRS usage by BAG library, and that it is on the client to properly handle what the passed in / out