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point.go
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point.go
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package locodedb
import (
"fmt"
"strconv"
"github.com/nspcc-dev/locode-db/pkg/locodedb"
)
// PointFromCoordinates converts a UN/LOCODE coordinates to a Point.
func PointFromCoordinates(crd *Coordinates) (locodedb.Point, error) {
if crd == nil {
return locodedb.Point{}, nil
}
cLat := crd.Latitude()
cLatDeg := cLat.Degrees()
cLatMnt := cLat.Minutes()
lat, err := toDecimal(cLatDeg[:], cLatMnt[:])
if err != nil {
return locodedb.Point{}, fmt.Errorf("could not parse latitude: %w", err)
}
if !cLat.Hemisphere().North() {
lat = -lat
}
cLng := crd.Longitude()
cLngDeg := cLng.Degrees()
cLngMnt := cLng.Minutes()
lng, err := toDecimal(cLngDeg[:], cLngMnt[:])
if err != nil {
return locodedb.Point{}, fmt.Errorf("could not parse longitude: %w", err)
}
if !cLng.Hemisphere().East() {
lng = -lng
}
return locodedb.Point{
Latitude: float32(lat),
Longitude: float32(lng),
}, nil
}
func toDecimal(intRaw, minutesRaw []byte) (float64, error) {
integer, err := strconv.ParseFloat(string(intRaw), 64)
if err != nil {
return 0, fmt.Errorf("could not parse integer part: %w", err)
}
decimal, err := minutesToDegrees(minutesRaw)
if err != nil {
return 0, fmt.Errorf("could not parse decimal part: %w", err)
}
return integer + decimal, nil
}
// minutesToDegrees converts minutes to decimal part of a degree.
func minutesToDegrees(raw []byte) (float64, error) {
minutes, err := strconv.ParseFloat(string(raw), 64)
if err != nil {
return 0, err
}
return minutes / 60, nil
}