Definition of "dynamic_geodetic_reference_frame"

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.

"dynamic_geodetic_reference_frame": {
  "type": "object",

"allOf": [{ "$ref": "#/definitions/object_usage" }],

  "properties": {
    "type": { "type": "string", "enum": ["DynamicGeodeticReferenceFrame"] },
    "name": { "type": "string" },
    "anchor": { "type": "string" },
    "anchor_epoch": { "type": "number" },
    "conventional_RS: {}
    "publication_date: { "type": date }
    "ellipsoid": { "$ref": "#/definitions/ellipsoid" },
    "prime_meridian": { "$ref": "#/definitions/prime_meridian" },
    "frame_reference_epoch": { "type": "number" },
    "$schema" : {},

"scope": {},
"area": {},
"bbox": {},
"vertical_extent": {},
"temporal_extent": {},
"usages": {},

    "remarks": {},
    "id": {}, "ids": {}
  },

"required" : [ "name", "ellipsoid", "prime_meridian", "frame_reference_epoch" ],

  "additionalProperties": false
},

"$comment": "[RL] See comment regarding usage under compound_crs."

"$comment": "[RL] 2x missing attributes and 3x missing data type."

"$comment": "[RL] In 19111/Topic2, ellipsoid is optional. This is because a geodetic geocentric frame/CRS does not require an ellipsoid (or indeed in theory can be associated with any ellipsoid). Because in practice few if any frames do not have a defined or recommended ellipsoid, EPSG makes the ellipsoid attribute mandatory."

"$comment": "In 19111/Topic2, prime meridian is a mandatory attribute. In WKT2, for reasons of brevity, prime meridian is conditional [mandatory if not Greenwich, else optional]."

Start with the referenced ProjJson v0-7 RL 2024-06-16.docx and the dynamic_geodetic_reference_frame definition shown in this issue. Resolve the proposed attributes, data types, usage fields, and required properties with the CRS SWG discussion; done means the agreed definition is reflected consistently in the CRS-JSON Encoding specification.