package continentsdb import ( "fmt" "os" locodedb "github.com/nspcc-dev/neofs-node/pkg/util/locode/db" "github.com/paulmach/orb" "github.com/paulmach/orb/geojson" "github.com/paulmach/orb/planar" ) const continentProperty = "Continent" // PointContinent goes through all polygons and returns the continent // in which the point is located. // // Returns locodedb.ContinentUnknown if no entry matches. // // All GeoJSON feature are parsed from file once and stored in memory. func (db *DB) PointContinent(point *locodedb.Point) (*locodedb.Continent, error) { var err error db.once.Do(func() { err = db.init() }) if err != nil { return nil, err } planarPoint := orb.Point{point.Longitude(), point.Latitude()} var ( continent string minDst float64 ) for _, feature := range db.features { if multiPolygon, ok := feature.Geometry.(orb.MultiPolygon); ok { if planar.MultiPolygonContains(multiPolygon, planarPoint) { continent = feature.Properties.MustString(continentProperty) break } } else if polygon, ok := feature.Geometry.(orb.Polygon); ok { if planar.PolygonContains(polygon, planarPoint) { continent = feature.Properties.MustString(continentProperty) break } } distance := planar.DistanceFrom(feature.Geometry, planarPoint) if minDst == 0 || minDst > distance { minDst = distance continent = feature.Properties.MustString(continentProperty) } } c := continentFromString(continent) return &c, nil } func (db *DB) init() error { data, err := os.ReadFile(db.path) if err != nil { return fmt.Errorf("could not read data file: %w", err) } features, err := geojson.UnmarshalFeatureCollection(data) if err != nil { return fmt.Errorf("could not unmarshal GeoJSON feature collection: %w", err) } db.features = features.Features return nil } func continentFromString(c string) locodedb.Continent { switch c { default: return locodedb.ContinentUnknown case "Africa": return locodedb.ContinentAfrica case "Asia": return locodedb.ContinentAsia case "Europe": return locodedb.ContinentEurope case "North America": return locodedb.ContinentNorthAmerica case "South America": return locodedb.ContinentSouthAmerica case "Antarctica": return locodedb.ContinentAntarctica case "Australia", "Oceania": return locodedb.ContinentOceania } }