Rotate objects towards gps coordinates

I want to rotate a 2D object towards specific real life GPS coordinates, which I can set (not the devices coordinates, rather any coordinates I type into the code. i.e. I dont need a UI to set it, I only want something like

 float latitude;
 float longitude;

which I can edit to hold any coordinates).
The app should work that when I rotate myself/device a 2D object rotates to always face the specific aforementioned coordinates.
Heres the code I have so far, which rotates a 2D object to always face forward, no matter the rotation of my phone.

 Gyroscope gyro;
 void Start () {
     //checks if the gyroscope is enabled
     gyro = Input.gyro;
     if(!gyro.enabled)
     {
         gyro.enabled = true;
     }
 }  

 void Update () 
 {
     //makes sure that the screen doesnt rotate if phone is rotated, 
     //even if auto rotate is on in phone settings, to ensure proper functionality.
     Screen.autorotateToLandscapeLeft = false;
     Screen.autorotateToLandscapeRight = false;
     Screen.autorotateToPortraitUpsideDown = false;  

     //The actual rotation code
     transform.Rotate (0, 0, -Input.gyro.rotationRateUnbiased.z);
 }

Im really new at Unity, so please answer very clearly.
Thanks!