This is a draft, expect sudden changes and come back later
General area forecast JSON format
This JSON format is meant for encoding meteorological and oceanographic forecast data for specific geographical areas and time periods.
Note that the specification is a work in progress and likely to change as long as Textforecast/3.0 is in beta.
Format
The area forecast uses the GeoJSON standard format, with additions from GeoJSON-T and JSON-FG for temporal dimension.
The forecasts for each area are grouped under a FeatureCollection as separate Features:
{
"type" : "FeatureCollection",
"lang" : "no",
"lastChange" : "2022-09-16T12:00:00Z",
"features" : [
{
"type" : "Feature",
"geometry" : {
"type" : "Polygon",
"coordinates" : [
[
[ 10.5443, 57.7603 ],
[ 11.5058, 57.8628 ],
[ 11.1707, 58.3362 ],
[ 10.9042, 58.9392 ],
[ 10.6532, 59.0437 ],
[ 10.2247, 58.9727 ],
[ 10.0482, 58.9565 ],
[ 9.7847, 58.93 ],
[ 9.595, 58.8522 ],
[ 9.3692, 58.7597 ],
[ 9.1537, 58.629 ],
[ 8.8087, 58.3963 ],
[ 10.5443, 57.7603 ]
]
]
},
"when": {
"interval": [
"2022-09-16T12:00:00Z",
"2022-09-17T00:00:00Z"
]
},
"properties" : {
"forecasttype" : "sea",
"name" : "Indre Skagerrak",
"text" : "Nordlig periodevis frisk bris 10 m/s. Oppholdsvær og god sikt. I kveld kan hende enkelte regnbyger med moderat sikt."
}
}
]
}
The lastChange attribute indicates when the forecast set was generated. Most forecast sets are produced in Norwegian and English as separate files, except for the land forecast which is only in Norwegian. The language is specified by the lang attribute.
Each separate forecast covers an area defined by a single Polygon with no holes. The name of the area (as used by MET Norway in our forecasts) is listed under properties in the name attribute. MultiPolygons might be used in a later version of Textforecast.
The interval which the forecast is valid for is specified in the when attribute, as (more or less) defined by the GeoJSON-T and JSON-FG standards.
Each forecast has a forecasttype attribute, which for land and coast is always normal. Other values are expected to follow when more forecasts are converted to GeoJSON.
The actual forecast then follows in the text attribute, using UTF-8 encoding.