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opengeospatial / dggs-2-equi-volume

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Issues arising from DGGS that are compliant with multiple parts of the DGGS spec #4

Open rggibb opened 3 years ago

rggibb commented 3 years ago

Multi-part compliance arises when a DGGS is:

  1. Based on a cartesian CRS and an equi-volume specialisation of Part 4 - Axis aligned
  2. Based on spherical or ellipsoidal and equi-volume or non-equivolume, where any surface slice is:
    • compliant with equi-area earth DGGS (Part 1 EAERS)
    • compliant with 2D axis aligned DGGS (Part 4)
  3. compliant with Part 2 & Part 3 - Temporal

Do we know what additional constraints might arise that needs addressing for these multi-part compliance DGGS? In which part should we address these additional constraints?

rggibb commented 3 years ago

An example of this between the parts issues is static vs dynamic datums and whether having a spatio-temporal dggs allows you to straddle these two perspectives.

rggibb commented 3 years ago

Action: @geofizzydrink to draft an appendix to either Part 2 or Part 3 that addresses dynamic vs static datums in 3D and 4D DGGS

geofizzydrink commented 3 years ago

After some pondering on this I think we need some more discussion. I see a couple of ways to address the drafting of the Dynamic Datums Appendix:

  1. The discussion of dynamic datums and DGGS could be split into two separate discussions included as appendices in both Part 2 and Part 3. In Part 2, the discussion could focus on the spatial aspects of dynamic datums and how a volumetric DGGS (as a spatial infrastructure) is not affected by the changes of that datum surface over time. In Part 3, the discussion could focus on how a spatio-temporal DGGS could encode the temporal epochs of that datum into the DGGS indexing schema and enable the indexed mapping of the datum surface in 4D.
  2. A separate "Best Practices"/"Technical Paper" could be drafted dealing with this and other important but ancillary (from the standards perspective) topics that may impact on the implementation of DGGS infrastructures.
  3. A single Annex discussion all aspects of 3D/4D DGGS and dynamic datums could be included in Part 2 and referenced in Part 3.

Happy for comments and suggestions here.