Determining Midpoint Between 2 Coordinates
In case someone need code in Swift, I have written library function in Swift to calculate the midpoint between MULTIPLE coordinates:
// /** Degrees to Radian **/
class func degreeToRadian(angle:CLLocationDegrees) -> CGFloat {
return ( (CGFloat(angle)) / 180.0 * CGFloat(M_PI) )
}
// /** Radians to Degrees **/
class func radianToDegree(radian:CGFloat) -> CLLocationDegrees {
return CLLocationDegrees( radian * CGFloat(180.0 / M_PI) )
}
class func middlePointOfListMarkers(listCoords: [CLLocationCoordinate2D]) -> CLLocationCoordinate2D {
var x = 0.0 as CGFloat
var y = 0.0 as CGFloat
var z = 0.0 as CGFloat
for coordinate in listCoords{
var lat:CGFloat = degreeToRadian(coordinate.latitude)
var lon:CGFloat = degreeToRadian(coordinate.longitude)
x = x + cos(lat) * cos(lon)
y = y + cos(lat) * sin(lon)
z = z + sin(lat)
}
x = x/CGFloat(listCoords.count)
y = y/CGFloat(listCoords.count)
z = z/CGFloat(listCoords.count)
var resultLon: CGFloat = atan2(y, x)
var resultHyp: CGFloat = sqrt(x*x+y*y)
var resultLat:CGFloat = atan2(z, resultHyp)
var newLat = radianToDegree(resultLat)
var newLon = radianToDegree(resultLon)
var result:CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: newLat, longitude: newLon)
return result
}
Detailed answer can be found here
Updated For Swift 5
func geographicMidpoint(betweenCoordinates coordinates: [CLLocationCoordinate2D]) -> CLLocationCoordinate2D {
guard coordinates.count > 1 else {
return coordinates.first ?? // return the only coordinate
CLLocationCoordinate2D(latitude: 0, longitude: 0) // return null island if no coordinates were given
}
var x = Double(0)
var y = Double(0)
var z = Double(0)
for coordinate in coordinates {
let lat = coordinate.latitude.toRadians()
let lon = coordinate.longitude.toRadians()
x += cos(lat) * cos(lon)
y += cos(lat) * sin(lon)
z += sin(lat)
}
x /= Double(coordinates.count)
y /= Double(coordinates.count)
z /= Double(coordinates.count)
let lon = atan2(y, x)
let hyp = sqrt(x * x + y * y)
let lat = atan2(z, hyp)
return CLLocationCoordinate2D(latitude: lat.toDegrees(), longitude: lon.toDegrees())
}
}
Just a hunch, but I noticed your lon2
and lat2
variables are being computed with M_PI/100
and not M_PI/180
.
double lon1 = _lo1.longitude * M_PI / 180;
double lon2 = _loc2.longitude * M_PI / 100;
double lat1 = _lo1.latitude * M_PI / 180;
double lat2 = _loc2.latitude * M_PI / 100;
Changing those to 180 might help you out a bit.