"schema": {
  "allOf": [
    {
      "format": "geometry-polygon"
    },
    "oneOf": [
      { 
        "type": "string",
        "contentMediaType": "application/gml+xml; version=3.2",
        "contentSchema": "http://schemas.opengis.net/gml/3.2.1/geometryBasic2d.xsd"   
      },
      { 
         "ref": "https://geojson.org/schema/Geometry.json
      }
    ]
  ]
}

"schema": {
  "oneOf": [
    {
      "type": "string",
      "contentMediaType": "application/gml+xml; version=3.2",
      "contentSchema": "http://schemas.opengis.net/gml/3.2.1/geometryBasic2d.xsd#Polygon"
    },
    {
      "ref": "https://geojson.org/schema/Polygon.json"
    }
  ]
}

"schema": {
  "format": "geometry-polygon"
}



"geoDataClass": "http://www.opengis.net/.../geodataclass/polygon-collection",
"schema": {
  "oneOf": [
    {
      "type": "string",
      "contentMediaType": "application/gml+xml; version=3.2",
      "contentSchema": "http://schemas.opengis.net/gml/3.2.1/??????.xsd"
    },
    {
      "ref": "https://geojson.org/schema/FeatureCollection.json"
    }
  ]
}



"geometryInput": "... wktstring ...";
"geometryInput": { JSON-Geometry },
"geometryInput": "... wktstring ... { JSON-Geometry }"