2022 09 02 Meeting Minutes - OpenNavigationSurface/crs_specification GitHub Wiki

Attendees: Weston, Jack, Chris, Glen

We discussed our responses to the assigned goals and questions and started to summarize in our recommendations. These were the notes from this round.

Goals and Guidance:

1.1 If 3D or compound the first field (horizontal) shall contain this information and supersede what is in the second (vertical) field.

1.2 See 1.1

1.3 See 1.1

1.4 The BAG rarely uses EPSG currently, so to prefer EPSG is a change from the current pattern. Defining as WKT is explicit as EPSG code definitions change change as previous versions are superseded. WKT should continue to be prefered. EPSG codes can be added to augment the WKT within the WKT.

1.5 OGC WKT2 allows for descriptions of CRS objects that contain limited transformations (DerivedCRS, BoundCRS). We believe this is sufficient to connect BAG data to well known datums which can then have well defined transformations for extended use.

1.6 We can check for if populated. Does BAG want to own checking if correct? If so we should find another library that is added as a dependency rather than building a WKT validator. If we are validating the WKT, do we require EPSG for registered WKT codes?

Questions:

2.1 See 1.1

2.2 We believe a BoundCRS provides this kind of context

2.3 This would break backward compatibility for users that cannot use WKT2, but does not interfere with the BAG library (or format) backward compatibility.

2.4 ?

2.5 Transformation histories are not required. Uncertainties should incorporate transformation (datum realization) uncertainties.