EPSG:9503 - CIGD11 + GCVD54 height (ft)

{
  "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
  "type": "CompoundCRS",
  "name": "CIGD11 + GCVD54 height (ft)",
  "components": [
    {
      "type": "GeographicCRS",
      "name": "CIGD11",
      "datum": {
        "type": "GeodeticReferenceFrame",
        "name": "Cayman Islands Geodetic Datum 2011",
        "ellipsoid": {
          "name": "GRS 1980",
          "semi_major_axis": 6378137,
          "inverse_flattening": 298.257222101
        }
      },
      "coordinate_system": {
        "subtype": "ellipsoidal",
        "axis": [
          {
            "name": "Geodetic latitude",
            "abbreviation": "Lat",
            "direction": "north",
            "unit": "degree"
          },
          {
            "name": "Geodetic longitude",
            "abbreviation": "Lon",
            "direction": "east",
            "unit": "degree"
          }
        ]
      }
    },
    {
      "type": "VerticalCRS",
      "name": "GCVD54 height (ft)",
      "datum": {
        "type": "VerticalReferenceFrame",
        "name": "Grand Cayman Vertical Datum 1954"
      },
      "coordinate_system": {
        "subtype": "vertical",
        "axis": [
          {
            "name": "Gravity-related height",
            "abbreviation": "H",
            "direction": "up",
            "unit": {
              "type": "LinearUnit",
              "name": "foot",
              "conversion_factor": 0.3048
            }
          }
        ]
      }
    }
  ],
  "scope": "Reversible geoid model transformation.",
  "area": "Cayman Islands - Grand Cayman.",
  "bbox": {
    "south_latitude": 19.21,
    "west_longitude": -81.46,
    "north_latitude": 19.41,
    "east_longitude": -81.04
  },
  "id": {
    "authority": "EPSG",
    "code": 9503
  }
}

{'crs_wkt': 'COMPOUNDCRS["CIGD11 + GCVD54 height '
            '(ft)",GEOGCRS["CIGD11",DATUM["Cayman Islands Geodetic Datum '
            '2011",ELLIPSOID["GRS '
            '1980",6378137,298.257222101,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["geodetic '
            'latitude '
            '(Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["geodetic '
            'longitude '
            '(Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]]],VERTCRS["GCVD54 '
            'height (ft)",VDATUM["Grand Cayman Vertical Datum '
            '1954"],CS[vertical,1],AXIS["gravity-related height '
            '(H)",up,LENGTHUNIT["foot",0.3048]]],USAGE[SCOPE["Reversible geoid '
            'model transformation."],AREA["Cayman Islands - Grand '
            'Cayman."],BBOX[19.21,-81.46,19.41,-81.04]],ID["EPSG",9503]]',
 'geographic_crs_name': 'CIGD11',
 'geopotential_datum_name': 'Grand Cayman Vertical Datum 1954',
 'grid_mapping_name': 'latitude_longitude',
 'horizontal_datum_name': 'Cayman Islands Geodetic Datum 2011',
 'inverse_flattening': 298.257222101,
 'longitude_of_prime_meridian': 0.0,
 'prime_meridian_name': 'Greenwich',
 'reference_ellipsoid_name': 'GRS 1980',
 'semi_major_axis': 6378137.0,
 'semi_minor_axis': 6356752.314140356}