Definition of "derived_geodetic_crs"

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.

"derived_geodetic_crs": {
"type": "object",

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

  "properties": {
    "type": { "type": "string",
              "enum": ["DerivedGeodeticCRS",
                       "DerivedGeographicCRS"] },
    "name": { "type": "string" },
    "base_crs": { "$ref": "#/definitions/geodetic_crs" },
    "conversion": { "$ref": "#/definitions/conversion" },
    "coordinate_system": { "$ref": "#/definitions/coordinate_system" },
    "coordinate_system": { "$ref": "#/definitions/geodetic_cs" },
    "$schema" : {},

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

    "remarks": {},
    "id": {}, "ids": {}
 },
 "required" : [ "name", "base_crs", "conversion", "coordinate_system" ],
 "additionalProperties": false
},

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

"$comment": "[RL] Although not supported by the Topic 2 data model, EPSG includes geodetic datum as a component of derived geodetic CRSs, this to negate the need to data mine for the information."

"$comment": "[RL] A geodetic CRS should be constrained to having a geodetic_cs."

Start with the derived_geodetic_crs schema fragment in this issue and compare it with the linked ProjJson v0-7 document. Review the surrounding CRS definitions and the CRS SWG discussion to identify the agreed model. Done means the definition and its constraints are resolved and consistently reflected in the schema.