Include bbox parameter in Subset clause 9.1

[jerstlouis]

Requirements already exist in requirements/coverage-bbox but they are not included anywhere in the text.

We discussed that servers should probably always implement both to maximize interoperability, therefore the bbox query parameter will be folded in together with subset in the same subsetting conformance class.

We will need some creativity to document that the bbox parameter can be unsupported for a particular target coverage, if it does not feature two spatial dimensions meaningful in the context of the bbox requirement module (as defined in Common).

[cmheazel]

So if we use a bbox with the /coverage request, would the bbox be evaluated against the domainset? Should we also add the dateTime parameter? Should we do the same thing for the domainset subset requirements class?

[jerstlouis]

Yes dateTime as well. DomainSet, RangeSet, Coverage should all work mostly the same way.

DomainSet is slightly different in that it returns a DomainSet based on what exists within the subset/bbox, rather than data.

The bbox subsets the spatial dimensions, which should also be described in the domainset if applicable. The bounds there are the bounds that the bbox query will be able to return data for, but the subset is allowed to extend beyond those bounds.

[cmheazel]

10/20/21 - bbox and datetime parameters should be added to Coverage and DomainSet subsetting.

Open question - if a bbox or datetime parameter is applied against a rangeset, does that mean that the response is a rangset clipped to the spatial and temporal extent defined by the bbox and datetime parameters? Should we add support for bbox and datetime to the Range Subset Requirements Class or create a new one?

[jerstlouis]

bbox and datetime parameters should be added to Coverage and DomainSet subsetting.

and rangeset.

if a bbox or datetime parameter is applied against a rangeset, does that mean that the response is a rangeset clipped to the spatial and temporal extent defined by the bbox and datetime parameters?

Yes.

Should we add support for bbox and datetime to the Range Subset Requirements Class or create a new one?

Range subset is a very different beast (range-subset= to select which bands / records fields to return). Are we rather talking here about RangeSet/Coverage/DomainSet subset?

If that's the case the pros and cons are:

• A) if it datetime and bbox are in the same conformance class as subset, then clients are more certain to have both and can rely on either
• B) if it is in a separate conformance class, then services have more flexibility in deciding which to implement, which might make life easier for services. That has the downside but making life harder for clients.

I myself have a preference for A, as I find it more important to make life easier for clients than for services.

[jerstlouis]

I believe the bbox parameter is now back in the subset clause. Latest edits at https://github.com/jerstlouis/ogcapi-coverages/tree/2023edits .

[jerstlouis]

2023 edits have been merged and the bbox is back.