Simple gps navigator in the mobile application (Unity)

using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

namespace InfinityCode.OnlineMapsExamples
{
    public class MoveMarkerOnRouteExample2 : MonoBehaviour
    {
        /// <summary>
        /// Start location name
        /// </summary>
        public string fromPlace = "Los Angeles";

        /// <summary>
        /// End location name
        /// </summary>
        public string toPlace = "Hollywood";

        /// <summary>
        /// Speed of movement (km/h).
        /// </summary>
        public float speed = 60;

        /// <summary>
        /// Move map to marker position
        /// </summary>
        public bool lookToMarker = false;

        /// <summary>
        /// Orient marker on next point.
        /// </summary>
        public bool orientMarkerOnNextPoint = false;

        /// <summary>
        /// Reference to marker
        /// </summary>
        private OnlineMapsMarker marker;

        /// <summary>
        /// Array of route points
        /// </summary>
        private OnlineMapsVector2d[] points;

        /// <summary>
        /// Current point index
        /// </summary>
        private int pointIndex = -1;

        /// <summary>
        /// Current step progress
        /// </summary>
        private double progress;

        private List<OnlineMapsVector2d> linePoints;

        private void Start()
        {
            // Looking for a route between locations.
            OnlineMapsGoogleDirections request = OnlineMapsGoogleDirections.Find(new OnlineMapsGoogleDirections.Params(fromPlace, toPlace));
            request.OnComplete += OnComplete;
        }

        private void OnComplete(string response)
        {
            Debug.Log("OnComplete");

            OnlineMapsGoogleDirectionsResult result = OnlineMapsGoogleDirections.GetResult(response);
            if (result == null || result.routes.Length == 0)
            {
                Debug.Log("Something wrong");
                Debug.Log(response);
                return;
            }

            OnlineMapsGoogleDirectionsResult.Route firstRoute = result.routes[0];
            List<OnlineMapsGoogleDirectionsResult.Step> steps = firstRoute.legs.SelectMany(l => l.steps).ToList();

            // Create a new marker in first point.
            marker = OnlineMapsMarkerManager.CreateItem(steps[0].start_location, "Car");

            // Gets points of route.
            points = steps.SelectMany(s => s.polylineD).ToArray();

            // Create a list of points that will be drawn and that will change when following a route
            linePoints = points.ToList();

            // Draw the route.
            OnlineMapsDrawingLine route = new OnlineMapsDrawingLine(linePoints, Color.red, 3);
            OnlineMapsDrawingElementManager.AddItem(route);

            pointIndex = 0;
        }

        private void Update()
        {
            if (pointIndex == -1) return;

            // Start point
            OnlineMapsVector2d p1 = points[pointIndex];

            // End point
            OnlineMapsVector2d p2 = points[pointIndex + 1];

            // Total step distance
            double dx, dy;
            OnlineMapsUtils.DistanceBetweenPoints(p1.x, p1.y, p2.x, p2.y, out dx, out dy);
            double stepDistance = Math.Sqrt(dx * dx + dy * dy);

            // Total step time
            double totalTime = stepDistance / speed * 3600;

            // Current step progress
            progress += Time.deltaTime / totalTime;

            OnlineMapsVector2d position;

            if (progress < 1)
            {
                position = OnlineMapsVector2d.Lerp(p1, p2, progress);
                marker.SetPosition(position.x, position.y);

                // Updating the first point of the drawn line
                linePoints[0] = position;

                // Orient marker
                if (orientMarkerOnNextPoint) marker.rotation = 1.25f - OnlineMapsUtils.Angle2D((Vector2)p1, (Vector2)p2) / 360f;
            }
            else
            {
                position = p2;
                marker.SetPosition(position.x, position.y);

                // Remove the first point of the drawn line
                linePoints.RemoveAt(0);
                pointIndex++;
                progress = 0;
                if (pointIndex >= points.Length - 1)
                {
                    Debug.Log("Finish");
                    pointIndex = -1;
                }
                else
                {
                    // Orient marker
                    if (orientMarkerOnNextPoint) marker.rotation = 1.25f - OnlineMapsUtils.Angle2D(p2, points[pointIndex + 1]) / 360;
                }
            }

            if (lookToMarker) OnlineMaps.instance.SetPosition(position.x, position.y);
            OnlineMaps.instance.Redraw();
        }
    }
}

using UnityEngine;

public class DirectionsFromLocation : MonoBehaviour
{
    public string googleAPIKey;
    public Vector2 destination = new Vector2(83.316583f, 17.710500f);

    private void Start()
    {
        if (string.IsNullOrEmpty(googleAPIKey)) Debug.LogWarning("Please specify Google API Key");

        OnlineMapsLocationService.instance.OnLocationInited += OnLocationInited;
    }

    private void OnLocationInited()
    {
        OnlineMapsGoogleDirections request = new OnlineMapsGoogleDirections(
            googleAPIKey, 
            OnlineMapsLocationService.instance.position, 
            destination);
        request.OnComplete += OnRequestComplete;
        request.Send();
    }

    private void OnRequestComplete(string response)
    {
        // Do something
    }
}