This is a draft, expect sudden changes and come back later
MetAlerts GeoJSON format
Overview
The output is a normal GeoJSON FeatureCollection, with each alert as an item in the Features array.
Each feature (alert) has three main parts:
- geometry: either a Polygon or a MultiPolygon, describing the geographical extent covered
- properties: various information pertaining to the alert, see below
- when: time interval when the alert is valid
Properties
All the fields have been extracted from the CAP files unchanged unless noted. For more detail, see the CAP v1 and v2 profile docs. All properties indicated in bold should always be present; most of the others are usually not available in CAP v1.
| Property | Description |
|---|---|
| altitude_above_sea_level § | lower boundary height over mean sea level (WGS84 geoid), in meters † |
| area | general name for the geographical area affected (same as areaDesc in CAP) |
| awareness_level | awareness level, including color |
| awarenessResponse | text describing recommended action/awareness (dependent on severity/certainty) |
| awarenessSeriousness | Text describing seriousness of the situation (dependent on severity/certainty) |
| awareness_type | type of phenomena, according the Meteoalarm classification |
| ceiling_above_sea_level § | lower boundary height over the WGS84 geoid, in meters † |
| certainty | one of “Observed”, “Likely” or “Possible” |
| consequences | consequences of the forecasted weather (related to instructions) |
| contact | URL to a contact information |
| county | an array of county codes (fylkesnr) ‡ |
| description | an extended human readable description of the hazard or event |
| eventAwarenessName | Name given severity, certainty and eventType |
| eventEndingTime | the expected end time of the subject event in the alert message |
| event | types of phenomena, see eventCode in the CAP v2 profile for a complete list |
| geographicDomain | area affected, either “land” or “marine” |
| id | the CAP id of the alert (same as identifier in CAP) |
| incidentName | name of incident, normally only given to extreme weather phenomena |
| instruction | recommended actions |
| municipality | an array of municipality codes (kommunenr) ‡ |
| resources | additional files available for download, see below |
| riskMatrixColor § | a combinationan of severity and certainty, either Green”, ‘Yellow”, “Orange” or ‘Red” |
| severity | “Extreme”, “Severe”, “Moderate” or “Minor” |
| status | “Actual” or “Test”, indicating if the alert is real or just dummy data |
| title | Short summary of the entire message, giving info about eventType, awareness_level (color), area and valid time (same as headline in CAP) |
| triggerLevel | observed weather will exceed the value specified here during? the indicated time period and area. |
| type | either “Alert” (for new alerts) or “Update” (for replacing existing alerts) |
| web | link to additional or reference information regarding this alert |
† Note that this is different from CAP, where the altitude and ceiling is in feet
‡ Same as administrativeId and MunicipalityId in CAP, but formatted for clarity. Only applicable for geographicDomain “land”
§ Only present in CAP v2 profile
Additional properties may be added in the future without further notice.
Resources
The resources field links to various external documents with additional data. There will always be a resource named “CAP file” which links to the original data. Other possible resources include maps and other graphics.
| Property | Description |
|---|---|
| description | caption describing the content of the external resource |
| mimeType | “application/xml” for CAP, usually “image/png” for others |
| uri | link to resource |
Example output
{
"type": "FeatureCollection"
"lang": "no",
"lastChange": "2024-03-05T14:08:36+00:00",
"features": [
{
"geometry": {
"coordinates": [
[
[ 6.3025, 58.2 ],
[ 6.4088, 58.3058 ],
[ 6.3185, 58.3302 ],
[ 6.2137, 58.3592 ],
[ 6.0827, 58.3988 ],
[ 5.9707, 58.4442 ],
[ 5.8422, 58.4987 ],
[ 5.6927, 58.5687 ],
[ 5.5955, 58.6587 ],
[ 5.5248, 58.6458 ],
[ 5.632, 58.5455 ],
[ 5.633, 58.5447 ],
[ 5.635, 58.5432 ],
[ 5.6767, 58.5157 ],
[ 5.6777, 58.5152 ],
[ 5.8387, 58.4185 ],
[ 5.8398, 58.4178 ],
[ 5.8508, 58.4118 ],
[ 5.8527, 58.411 ],
[ 6.0673, 58.3112 ],
[ 6.3025, 58.2 ],
[ 6.3025, 58.2 ]
]
],
"type": "Polygon"
},
"properties": {
"altitude_above_sea_level": "0",
"area": "Åna-Sira - Obrestad",
"awarenessResponse": "Følg med",
"awarenessSeriousness": "Utfordrende situasjon",
"awareness_level": "2; yellow; Moderate",
"awareness_type": "1; Wind",
"ceiling_above_sea_level": "900",
"certainty": "Observed",
"consequences": "Sjøen bygger seg opp og det kan være farlig å være ute i småbåt Grov sjø og hvitt skum fra bølgetopper som brekker. ",
"contact": "https://www.met.no/kontakt-oss",
"county": [],
"description": " I dag, tirsdag, fortsatt øst og sørøst stiv kuling 15 m/s, minkende i ettermiddag.",
"event": "gale",
"eventAwarenessName": "Kuling",
"eventEndingTime": "2024-03-05T15:00:00+00:00",
"geographicDomain": "marine",
"id": "2.49.0.1.578.0.20240305051538.094",
"instruction": "Vurder å la båten ligge. ",
"resources": [
{
"description": "CAP file",
"mimeType": "application/xml",
"uri": "http://localhost:3000/weatherapi/metalerts/2.0/current?cap=2.49.0.1.578.0.20240305051538.094"
}
],
"riskMatrixColor": "Yellow",
"severity": "Moderate",
"status": "Actual",
"title": "Kuling, gult nivå, Åna-Sira - Obrestad, 2024-03-04T17:00:00+00:00, 2024-03-05T15:00:00+00:00",
"triggerLevel": "13.9m/s",
"type": "Update",
"web": "https://www.met.no/vaer-og-klima/ekstremvaervarsler-og-andre-farevarsler/vaerfenomener-som-kan-gi-farevarsel-fra-met/kuling-stormvarsel-for-kyst-og-naere-fiskebanker"
},
"type": "Feature",
"when": {
"interval": [
"2024-03-04T17:00:00+00:00",
"2024-03-05T15:00:00+00:00"
]
}
}
],
}