Thank you for answering, I fixed the problem. It was quite a hurdle because Im shaky with my trigonometry.

Would it be possible to see your solution?  I've been having the same problem as you and was pulling my hair out.   Could you help?  PM sent.  Thanks.

Online Maps Location Service is just a wrapper for Unity Location Service and Unity Compass.
Online Maps Location Service takes this value from Unity Compass trueHeading.

Yes, in Google Maps it works much better.
But using Online Maps, if you do not like how some feature works (in your case, the compass), you can implement it yourself without modifying the code, and get the behavior that you need.

I tried to make a script that combined the data from the gyro and the compass, but so far without success.
I think this is the right direction to work around the problem. But I can be wrong.

Here is the video, it can't be attached because it's too large (10 mb)

https://www.dropbox.com/s/0gfir9y4q7s3n … 1.m4v?dl=0

The problem is not in your code, and not in Online Maps.
The problem is in the sensor values.
Use Mathf.Lerp to smooth the values of the compass sensor.

Something like:

using System;
using UnityEngine;

public class LerpCompassValue:MonoBehaviour
{
    public GameObject cam2;
    private float compassValue;
    private float currentCompassValue;
    private bool isFirstValue = true;

    private void Start()
    {
        OnlineMapsLocationService.instance.OnCompassChanged += OnCompassChanged;
    }

    private void OnCompassChanged(float f)
    {
        currentCompassValue = f;
        if (isFirstValue)
        {
            compassValue = f;
            isFirstValue = false;
        }

        if (currentCompassValue - compassValue > 0.5) compassValue += 1;
        else if (currentCompassValue - compassValue < -0.5) compassValue -= 1;
    }

    private void Update()
    {
        if (isFirstValue) return;
        if (Math.Abs(currentCompassValue - compassValue) < float.Epsilon) return;
        if (Mathf.Abs(currentCompassValue - compassValue) < 0.001f) compassValue = currentCompassValue;
        else compassValue = Mathf.Lerp(compassValue, currentCompassValue, 0.05f);

        OnlineMapsTileSetControl.instance.cameraRotation.y = compassValue * 360;
        Vector3 rot = new Vector3(0f, compassValue * 360f, 0f);

        cam2.transform.eulerAngles = rot;
    }
}

    public class RotateCameraByCompassExample : MonoBehaviour
    {

        public GameObject cam2;

        private void Start()
        {
            // Subscribe to compass event
            OnlineMapsLocationService.instance.OnCompassChanged += OnCompassChanged;
        }

        /// <summary>
        /// This method is called when the compass value is changed.
        /// </summary>
        /// <param name="f">New compass value (0-1)</param>
        private void OnCompassChanged(float f)
        {
            // Rotate the camera.
            OnlineMapsTileSetControl.instance.cameraRotation.y = f * 360;

            Vector3 rot = new Vector3 (0f, f * 360f, 0f);

            cam2.transform.eulerAngles = rot;

        }
    }

The problem is that the rotation of my gameobject is veryyyy jerky. It's unusable, am I doing it wrong?