Center coordinate of a set of CLLocationsCoordinate2D

Hmm... it depends how you define the centre of the points. Does it depend on the distribution etc...

An easy way to do it is as follows...

//find rect that encloses all coords

float maxLat = -200;
float maxLong = -200;
float minLat = MAXFLOAT;
float minLong = MAXFLOAT;

for (int i=0 ; i<[locations count] ; i++) {
    CLLocationCoordinate2D location = [locations objectAtIndex:i];

    if (location.latitude < minLat) {
        minLat = location.latitude;
    }

    if (location.longitude < minLong) {
        minLong = location.longitude;
    }

    if (location.latitude > maxLat) {
        maxLat = location.latitude;
    }

    if (location.longitude > maxLong) {
        maxLong = location.longitude;
    }
}

//Center point

CLLocationCoordinate2D center = CLLocationCoordinate2DMake((maxLat + minLat) * 0.5, (maxLong + minLong) * 0.5);

This will give the center of the rect covering all the points. However it does not take the spread into account.

i.e.

. = point
X = centre

.....               X                   .

EDIT

Corrected some of the maths.

I know it's really late but someone could read this and help himself Using Fogmeister answer you could create a MKCoordinateRegion

CLLocationDegrees minLat,minLng,maxLat,maxLng;
for(CLLocationCoordinate2D coordinate in coordinates) {
    minLat = MIN(minLat, coordinate.latitude);
    minLng = MIN(minLng, coordinate.longitude);

    maxLat = MAX(maxLat, coordinate.latitude);
    maxLng = MAX(maxLng, coordinate.longitude);
}

CLLocationCoordinate2D coordinateOrigin = CLLocationCoordinate2DMake(minLat, minLng);
CLLocationCoordinate2D coordinateMax = CLLocationCoordinate2DMake(maxLat, maxLng);

MKMapPoint upperLeft = MKMapPointForCoordinate(coordinateOrigin);
MKMapPoint lowerRight = MKMapPointForCoordinate(coordinateMax);

//Create the map rect
MKMapRect mapRect = MKMapRectMake(upperLeft.x,
                                  upperLeft.y,
                                  lowerRight.x - upperLeft.x,
                                  lowerRight.y - upperLeft.y);

//Create the region
MKCoordinateRegion region = MKCoordinateRegionForMapRect(mapRect);

//THIS HAS THE CENTER, it should include spread
CLLocationCoordinate2D centerCoordinate = region.center;

Greetings!!!

You can also get both the center of an array of CLLocationCoordinate2Ds and a span.

extension MKCoordinateRegion {

  init(coordinates: [CLLocationCoordinate2D]) {
    var minLatitude: CLLocationDegrees = 90.0
    var maxLatitude: CLLocationDegrees = -90.0
    var minLongitude: CLLocationDegrees = 180.0
    var maxLongitude: CLLocationDegrees = -180.0

    for coordinate in coordinates {
      let lat = Double(coordinate.latitude)
      let long = Double(coordinate.longitude)
      if lat < minLatitude {
        minLatitude = lat
      }
      if long < minLongitude {
        minLongitude = long
      }
      if lat > maxLatitude {
        maxLatitude = lat
      }
      if long > maxLongitude {
        maxLongitude = long
      }
    }

    let span = MKCoordinateSpanMake(maxLatitude - minLatitude, maxLongitude - minLongitude)
    let center = CLLocationCoordinate2DMake((maxLatitude - span.latitudeDelta / 2), (maxLongitude - span.longitudeDelta / 2))
    self.init(center: center, span: span)
  }
}

Usage:

let region = MKCoordinateRegion(coordinates: coordinates)
region.center
region.span