GPX Line car

/// <summary>
/// Current progress value (0-1)
/// </summary>
public float progress;
    
/// <summary>
/// Points of the route
/// </summary>
private OnlineMapsVector2d[] points;

private void UpdateMarkerPosition()
{
    // Calculate the total distance of the route.
    double totalDistanceKm = 0;
    for (int i = 0; i < points.Length - 1; i++)
    {
        OnlineMapsVector2d p1 = points[i];
        OnlineMapsVector2d p2 = points[i + 1];
        totalDistanceKm += OnlineMapsUtils.DistanceBetweenPoints(p1.x, p1.y, 0, p2.x, p2.y, 0);
    }
    
    // Calculate the distance covered.
    double coveredDistanceKm = totalDistanceKm * Mathf.Clamp01(progress);

    for (int i = 0; i < points.Length - 1; i++)
    {
        // Calculate the distance between the current and next point.
        OnlineMapsVector2d p1 = points[i];
        OnlineMapsVector2d p2 = points[i + 1];
        double distance = OnlineMapsUtils.DistanceBetweenPoints(p1.x, p1.y, 0, p2.x, p2.y, 0);
        
        // If the distance covered is greater than the distance between the current and next point,
        // subtract the distance between the current and next point from the distance covered.
        if (coveredDistanceKm > distance)
        {
            coveredDistanceKm -= distance;
        }
        // If the distance covered is less or equal than the distance between the current and next point,
        // calculate the position of the marker.
        else
        {
            double lng = p1.x + (p2.x - p1.x) * coveredDistanceKm / distance;
            double lat = p1.y + (p2.y - p1.y) * coveredDistanceKm / distance;
            marker.SetPosition(lng, lat);
            break;
        }
    }
}