Definition of "derived_vertical_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_vertical_crs": {
  "type": "object",

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

  "properties": {
    "type": { "type": "string",
              "enum": ["DerivedVerticalCRS"] },
    "name": { "type": "string" },
    "base_crs": { "$ref": "#/definitions/vertical_crs" },
    "conversion": { "$ref": "#/definitions/conversion" },

"coordinate_system": { "$ref": "#/definitions/coordinate_system" }, STRIKE THIS DEFINITION, REPLACE WITH:
"coordinate_system": { "$ref": "#/definitions/vertical_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] A vertical CRS should be constrained to having a vertical_cs."

Read the linked ProjJson v0-7 document and locate the derived_vertical_crs definition in the repository schema. Compare the proposed coordinate_system reference and struck usage properties with the surrounding CRS definitions; done means the agreed definition is reflected in the schema.