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package nmea
const (
// TypeDTM type of DTM sentence for Datum Reference
TypeDTM = "DTM"
)
// DTM - Datum Reference
// https://gpsd.gitlab.io/gpsd/NMEA.html#_dtm_datum_reference
//
// Format: $--DTM,ref,x,llll,c,llll,c,aaa,ref*hh<CR><LF>
// Example: $GPDTM,W84,,0.0,N,0.0,E,0.0,W84*6F
// Example: $GPDTM,W84,,00.0000,N,00.0000,W,,W84*53
type DTM struct {
BaseSentence
LocalDatumCode string // Local datum code (W84,W72,S85,P90,999)
LocalDatumSubcode string // Local datum subcode. May be blank.
LatitudeOffsetMinute float64 // Latitude offset (minutes) (negative if south)
LongitudeOffsetMinute float64 // Longitude offset (minutes) (negative if west)
AltitudeOffsetMeters float64 // Altitude offset in meters
DatumName string // Reference datum name. What’s usually seen here is "W84", the standard WGS84 datum used by GPS.
}
// newDTM constructor
func newDTM(s BaseSentence) (Sentence, error) {
p := NewParser(s)
p.AssertType(TypeDTM)
m := DTM{
BaseSentence: s,
LocalDatumCode: p.String(0, "local datum code"),
LocalDatumSubcode: p.String(1, "local datum subcode"),
LatitudeOffsetMinute: p.Float64(2, "latitude offset minutes"),
LongitudeOffsetMinute: p.Float64(4, "longitude offset minutes"),
AltitudeOffsetMeters: p.Float64(6, "altitude offset offset"),
DatumName: p.String(7, "datum name"),
}
if p.String(3, "latitude offset direction") == South {
m.LatitudeOffsetMinute *= -1
}
if p.String(5, "longitude offset direction") == West {
m.LongitudeOffsetMinute *= -1
}
return m, p.Err()
}
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