Definition of "transformation"

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.

"transformation": {
  "type": "object",

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

  "properties": {
    "type": { "type": "string", "enum": ["Transformation"] },
    "name": { "type": "string" },
    "source_crs": { "$ref": "#/definitions/crs" },
    "target_crs": { "$ref": "#/definitions/crs" },
    "interpolation_crs": { "$ref": "#/definitions/crs" },
    "method": { "$ref": "#/definitions/method" },
    "parameters": {
        "type": "array",
        "items": { "$ref": "#/definitions/parameter_value" }
    },
    "accuracy": { "type": "string" },
    "$schema" : {},

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

    "remarks": {},
    "id": {}, "ids": {}
  },
  "required" : [ "name", "source_crs", "target_crs", "method", "parameters" ],
  "additionalProperties": false
},

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

"$comment": "[RL] See comment under method."

Read the linked ProjJson v0-7 document and review the transformation schema shown in the issue. Examine the highlighted object_usage inheritance and usage fields, along with the comments under compound_crs and method. Done means the CRS SWG discussion reaches an agreed definition and the schema reflects that decision.