MET Norway MetAlerts GeoJSON Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://api.met.no/weatherapi/metalerts/schemas/alert",
  "title": "MET Norway MetAlerts GeoJSON Schema",
  "description": "Schema for weather alert GeoJSON responses from the MET Norway MetAlerts API.",
  "type": "object",
  "required": ["type", "features"],
  "properties": {
    "type": {
      "type": "string",
      "const": "FeatureCollection"
    },
    "features": {
      "type": "array",
      "description": "Array of weather alert features",
      "items": {
        "$ref": "#/definitions/AlertFeature"
      }
    }
  },
  "definitions": {
    "AlertFeature": {
      "title": "Weather Alert Feature",
      "type": "object",
      "required": ["type", "geometry", "properties"],
      "properties": {
        "type": {
          "type": "string",
          "const": "Feature"
        },
        "geometry": {
          "type": "object",
          "description": "Geographic area affected by the alert (Polygon or MultiPolygon)",
          "properties": {
            "type": {
              "type": "string",
              "enum": ["Polygon", "MultiPolygon"]
            },
            "coordinates": {
              "type": "array"
            }
          }
        },
        "properties": {
          "$ref": "#/definitions/AlertProperties"
        }
      }
    },
    "AlertProperties": {
      "title": "Weather Alert Properties",
      "type": "object",
      "properties": {
        "id": {
          "type": "string",
          "description": "CAP message identifier URI",
          "examples": ["2.49.0.1.578.0.20240115120000.001"]
        },
        "title": {
          "type": "string",
          "description": "Human-readable alert title"
        },
        "description": {
          "type": "string",
          "description": "Detailed description of the weather event"
        },
        "instruction": {
          "type": "string",
          "description": "Recommended actions for the public"
        },
        "event": {
          "type": "string",
          "description": "Weather event type",
          "enum": [
            "blowingSnow", "forestFire", "gale", "ice", "icing",
            "lightning", "polarLow", "rain", "rainFlood", "snow",
            "stormSurge", "wind"
          ]
        },
        "eventAwarenessName": {
          "type": "string",
          "description": "Human-readable event awareness name",
          "examples": ["Extreme wind", "Heavy rain", "Heavy snow"]
        },
        "severity": {
          "type": "string",
          "description": "CAP severity level",
          "enum": ["Extreme", "Severe", "Moderate", "Minor", "Unknown"]
        },
        "certainty": {
          "type": "string",
          "description": "CAP certainty level",
          "enum": ["Observed", "Likely", "Possible", "Unlikely", "Unknown"]
        },
        "urgency": {
          "type": "string",
          "description": "CAP urgency level",
          "enum": ["Immediate", "Expected", "Future", "Past", "Unknown"]
        },
        "awareness_level": {
          "type": "string",
          "description": "Color-coded awareness level used by MET Norway",
          "enum": ["2; yellow; Moderate", "3; orange; Severe", "4; red; Extreme"]
        },
        "awareness_type": {
          "type": "string",
          "description": "Type of awareness alert"
        },
        "onset": {
          "type": "string",
          "format": "date-time",
          "description": "When the alert period begins"
        },
        "expires": {
          "type": "string",
          "format": "date-time",
          "description": "When the alert expires"
        },
        "published": {
          "type": "string",
          "format": "date-time",
          "description": "When the alert was published/issued"
        },
        "updated": {
          "type": "string",
          "format": "date-time",
          "description": "When the alert was last updated"
        },
        "msgType": {
          "type": "string",
          "description": "CAP message type",
          "enum": ["Alert", "Update", "Cancel", "Ack", "Error"]
        },
        "status": {
          "type": "string",
          "description": "CAP status",
          "enum": ["Actual", "Exercise", "System", "Test", "Draft"]
        },
        "county": {
          "type": "array",
          "description": "Affected Norwegian county codes (land alerts only)",
          "items": {
            "type": "string",
            "pattern": "^\\d{2}$"
          }
        },
        "geographicDomain": {
          "type": "string",
          "description": "Geographic domain of the alert",
          "enum": ["land", "marine"]
        },
        "incidentName": {
          "type": "string",
          "description": "Named incident identifier assigned to major (red) events"
        },
        "cap": {
          "type": "string",
          "format": "uri",
          "description": "URL to the full CAP XML message"
        },
        "resources": {
          "type": "array",
          "description": "Associated resources such as web links and images",
          "items": {
            "type": "object",
            "properties": {
              "description": {
                "type": "string"
              },
              "mimeType": {
                "type": "string"
              },
              "uri": {
                "type": "string",
                "format": "uri"
              }
            }
          }
        }
      }
    }
  }
}