Scope of top level entities if adapted from the ProjJSON schema

NOTE: Markdown does not support highlighting in color, so bold/italic has been used to highlight the material being discussed. This issue is extracted from the document submitted by Roger Lott at https://github.com/opengeospatial/CRS-JSON-Encoding/blob/main/ProjJson%20v0-7%20RL%202024-06-16.docx for discussion at the CRS SWG meeting OGC held during the Montreal June 2024 TC meeting.

"oneOf": [
{ "$ref": "#/definitions/crs" },
{ "$ref": "#/definitions/datum" },
{ "$ref": "#/definitions/datum_ensemble" },
{ "$ref": "#/definitions/ellipsoid" },
{ "$ref": "#/definitions/prime_meridian" },
{ "$ref": "#/definitions/single_operation" },
{ "$ref": "#/definitions/concatenated_operation" },
{ "$ref": "#/definitions/coordinate_metadata" }
],

The ProjJSON schema includes some entities at the top level that are lower level entities in the CRS Abstract Specifications (ISO 19111 and OGC topic 2). Should scope be limited to 'top level' entities, i.e. CRSs and coordinate operations? If so, remove from this list the lower level entities: datum, datum_ensemble, ellipsoid and prime meridian. (These [and other] lower level entities will be needed as components of the top level entities so are not eliminated from the schema, just changing the schema to define only top level entities)."

Beginne mit dem verlinkten ProjJSON v0-7-Vorschlag und vergleiche dessen oneOf-Liste mit den CRS Abstract Specifications (ISO 19111 und OGC Topic 2). Bestätige, ob datum, datum_ensemble, ellipsoid und prime_meridian als Entitäten der obersten Ebene dazugehören; abgeschlossen ist die Aufgabe, wenn der Umfang abgestimmt ist und das Schema diese Entscheidung widerspiegelt.