json_schema: {
      "title": "IconSymbol3DLayer Resource",
      "type": "object",
      "$schema": "http://json-schema.org/draft-04/schema",
      "description": "The shape (primitive) or image URL (href) used to visualize the features.",
      "properties": {
          "dataURI": {
              "type": "string",
              "description": "an image encoded as base64 string, starting with `data:image/`",
              "pattern": "^data:image/(.|\\n|\\r)+$"
          },
          "href": {
              "description": "URL to the returned image.",
              "oneOf": [
                  {
                      "type": "string",
                      "description": "An absolute URL",
                      "pattern": "^https?://.+$"
                  },
                  {
                      "type": "string",
                      "description": "A relative path starting with ./",
                      "pattern": "^\\./.+$"
                  }
              ]
          },
          "primitive": {
              "type": "string",
              "description": "Specifies the type of symbol used.",
              "enum": [
                  "circle",
                  "cross",
                  "kite",
                  "square",
                  "triangle",
                  "x"
              ]
          }
      },
      "oneOf": [
          {
              "required": [
                  "primitive"
              ]
          },
          {
              "required": [
                  "href"
              ]
          },
          {
              "required": [
                  "dataURI"
              ]
          }
      ],
      "additionalProperties": false
  }