Question

I’ve been stuck with this problem for quite a while now.

I’m building a custom navigation application in iOS, I have an array of CLLocations so in array 0 I get the last two co-ordinates, get the bearing of those, then in array 1 I get the bearing of the first two co-ordinates.

I then want to calculate the angle of the turn relative to the path(Path 0 in this case) they’re currently on, so I can figure out which way the user is turning.

I’ve tried quite a few methods found on here with no success. Has anyone any tips or recommendations

Any help would be greatly appreciated, thanks!

Update: After reading the comments I went back and looked again as I was sure I had it right, turns out my points were stored wrong and the method I was using was right!

What worked best for me was getting the bearing of both paths, Taking the current path bearing from the previous path, and following this guideline.

if(self.turnAngle <= 165){
    self.turnString = LEFT;
}else if( self.turnAngle >= 165 && self.turnAngle <= 205 ){
    self.turnString = STRAIGHT;
}else if( self.turnAngle >= 205 ){
    self.turnString = RIGHT;
}

Answer 1

Update: After reading the comments I went back and looked again as I was sure I had it right, turns out my points were stored wrong and the method I was using was right!

What worked best for me was getting the bearing of both paths, Taking the current path bearing from the previous path, and following this guideline.

 float previousPathBearing = //get bearing
 float currentPathBearing = //get bearing
 float angle = previousPathBearing - currentPathBearing;
 angle = angle<0?-angle:angle;


if(angle<= 165){
    //LEFT;
}else if( angle>= 165 && angle <= 205 ){
    //STRAIGHT;
}else if( angle >= 205 ){
    //RIGHT;
}

You’ll have to excuse typos/silly mistakes as I’m quite tired, but this worked fine for me!