Guidance of usage of parameterGroup

[webb-ben]

I am looking to group EDR parameters based on their common features. The parameterGroup appears to address this, but I cannot find any guidance on the implementation of the parameterGroup outside of the CoverageJSON repository itself.

I am using it inside my CovJSON response conformant with opengeospatial/CoverageJSON#138, (example)

I am finding it useful to also use the parameterGroup on the collections and collection view. These correspond to times when the parameters objects (related to #633) are also present in the JSON response, and are helpful for clients to determine which collections they may be interested in. See example collections.json or collection.json

I understand that the OpenAPI determines precisely what the EDR implementation may support, but I am struggling to understand where the parameterGroup is supposed to fit into the specification.

[m-burgoyne]

parameterGroup is a concept from CoverageJSON. Currently, the EDR Query API does not support parameter_groups. Instead, it requires the client to explicitly request each parameter needed in the response data.

[webb-ben]

I was not necessarily referring to the parameterGroup as an input to an EDR query so much as inquiring about the purpose of :master/.../oas30/schemas/parameterGroup.yaml and :master/.../oas31/schemas/parameterGroup.yaml.

I am modifying EDR query param parameter-name to filter on collection specific parameters as well as parameter groups. In that way the set of members are substituted if a parameterGroup is provided.

To generate the files provided above, I used the following queries:
/collections/resviz-edr/locations/1?parameter-name=Storage&limit=1
/collections?parameter-name=Storage
/collections/usace-edr

This issue is as much asking if so far, EDR has an opinions on the use or disuse of parameterGroup(s). Are the parameterGroup schemas in this repository to conform to CoverageJSON?

[chris-little]

@webb-ben The CoverageJSON parameterGroup mentioned in the schemas are for the CoverageJSON example responses.
At present the EDR API as no opinion on Groups. the SWG suggests that the discussion continues in the CoverageJSON repo under issue #138.

[PaulVanSchayck]

We've been considering the use of the CovJSON ParameterGroup to annotate quality flag variables which are directly associated to, for example, observational variables. In the CF conventions this is referred to as ancillary data. See also this ticket opengeospatial/CoverageJSON#207 in the CovJSON repository.

What we're lacking from the EDR spec is how to handle these ancillary variables. We're considering to always output the ancillary variables when querying for the primary variable. In the CovJSON output, the ancillary variables can be defined (somewhat) in a ParameterGroup. But in EDR there is no way to annotate this beforehand.

An option could be to add something like ancillaryVariables: list[str] to Parameter. What are your thoughts on this?