Get geographical direction using magnetic heading

Question

How to calculate magnetic heading value to get geographical direction i.e., North, North-East, East, East-South, South, South-West, West, West-North?

As magnetic heading returns only value of degree and its required for me to show the geographical direction, on the basis of continuous updated magnetic heading.

How can I make it possible?

Answer 1

Below is the code that I have used to display continuously updating geographical direction.

        CGFloat currentHeading = newHeading.magneticHeading;
        NSString *strDirection = [[NSString alloc] init];

        if(gradToRotate >23 && gradToRotate <= 67){
              strDirection = @"NE";
        } else if(gradToRotate >68 && gradToRotate <= 112){
              strDirection = @"E";
        } else if(gradToRotate >113 && gradToRotate <= 167){
              strDirection = @"SE";
        } else if(gradToRotate >168 && gradToRotate <= 202){
              strDirection = @"S";
        } else if(gradToRotate >203 && gradToRotate <= 247){
              strDirection = @"SW";
        } else if(gradToRotate >248 && gradToRotate <= 293){
              strDirection = @"W";
        } else if(gradToRotate >294 && gradToRotate <= 337){
              strDirection = @"NW";
        } else if(gradToRotate >=338 || gradToRotate <= 22){
              strDirection = @"N";
        }

It is working fine at my end. Masters are welcome to let me know if any modification required.

Answer 2

Try this example offered by Matt Neuburg on Github. https://github.com/mattneub/Programming-iOS-Book-Examples/blob/master/bk2ch22p775heading/ch35p1035heading/ViewController.swift

func locationManager(manager: CLLocationManager, didUpdateHeading newHeading: CLHeading) {
    var h = newHeading.magneticHeading
    let h2 = newHeading.trueHeading // will be -1 if we have no location info
    print("\(h) \(h2) ")
    if h2 >= 0 {
        h = h2
    }
    let cards = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"]
    var dir = "N"
    for (ix, card) in cards.enumerate() {
        if h < 45.0/2.0 + 45.0*Double(ix) {
            dir = card
            break
        }
    }
    print(dir)
}

It is perfect!