(http://csharppad.com/gist/0a3f5e5c833e4c983abe7654450f1b9c)

gps.cs

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* This Gist was created at CSharpPad.com
* To run this file, open http://csharppad.com/gist/0a3f5e5c833e4c983abe7654450f1b9c
**********/

using UnityEngine;
using UnityEngine.UI;
using System;

public class GPSCtrl : MonoBehaviour
{

	public Text distance_label;
	public GameObject distanceObject;

	// *** DELETE WHEN DONE - text labels for testing
	public Text testP1;
	public Text testP2;
	public Text testMsg;
	public Text testMsg2;
	public GameObject p1Object;
	public GameObject p2Object;
	public GameObject test;
	public GameObject test2;


	public double long1 = 0;
	public double lat1 = 0;

	public double long2 = 0;
	public double lat2 = 0;

	public double currLong;
	public double currLat;

	public double distanceWalked = 0;

	void Start ()
	{
		distance_label = distanceObject.GetComponent<Text> ();

		// *** DELETE WHEN DONE - text labels for testing
		testP1 = p1Object.GetComponent<Text> ();
		testP2 = p2Object.GetComponent<Text> ();
		testMsg = test.GetComponent<Text> ();
		testMsg2 = test2.GetComponent<Text> ();

		distance_label.text = "You and your blobs have walked 0.00 km this trip.";

	}


	void Update ()
	{

			GetCurrentLocation ();
			HasTraveled ();

		testP1.text = "<Point 1 Coordinates> Lat: " + lat1 + ", Long: " + long1;
		testP2.text = "<Point 2 Coordinates> Lat: " + lat2 + ", Long: " + long2;

		// Compare GPS coordinates rounded to 4 decimal places
		/*
		if (latRounded1 != latRounded2 || longRounded1 != longRounded2) {
			testMsg.text = "Lat/Long don't match.";
			distanceWalked += CalculateDistance (longRounded1, latRounded1, longRounded2, latRounded2);
			distance_label.text = "You and your blobs have walked " + distanceWalked + " km.";
			long1 = long2;
			lat1 = lat2;
		}
		*/
	}

	public void GetCurrentLocation()
	{
		testMsg.text = "Location status: " + Input.location.status;

		if (Input.location.status == LocationServiceStatus.Running) {
			lat2 = Input.location.lastData.latitude;
			long2 = Input.location.lastData.longitude;
		}
	}

	public void HasTraveled()
	{
			if (lat1 != lat2 || long1 != long2) {
				testMsg2.text = "Inside HasTraveled()";
				distanceWalked = CalculateDistance (lat1, long1, lat2, long2);
				distance_label.text = "You and your blobs have walked " + Math.Round (distanceWalked, 2) + " km this trip.";
				long1 = long2;
				lat1 = lat2;
		}
	}

	/// <summary>
	/// Makes a call to start GPS service when Start button is clicked.
	/// </summary>
	public void StartButtonClicked ()
	{
		Debug.Log ("Start button clicked...");
		StartCoroutine (StartLocationService ());
	}

	/// <summary>
	/// Stops GPS service when Stop button is clicked.
	/// </summary>
	public void StopButtonClicked ()
	{
		Debug.Log ("Stop button clicked...");
		Input.location.Stop ();
		distance_label.text = "Stopped.";
	}

	public void ResetButtonClicked()
	{
		Debug.Log("Reset button clicked...");
		distanceWalked = 0;
		Input.location.Stop ();

		Debug.Log ("distanceWalked after reset: " + distanceWalked);

	}



	/// <summary>
	/// Starts the location service.
	/// </summary>
	IEnumerator StartLocationService ()
	{
		// First, check if user has location service enabled
		if (!Input.location.isEnabledByUser)
			//yield break;
			distance_label.text = "Not initialized";

		// Start service before querying location
		Input.location.Start (5f, 5f);	// accuracy = 5m, update frequency = 5m


		// Wait until service initializes
		int maxWait = 20;
		while (Input.location.status == LocationServiceStatus.Initializing && maxWait > 0) {
			yield return new WaitForSeconds (1);
			maxWait--;
		}

		// Service didn't initialize in 20 seconds
		if (maxWait < 1) {
			distance_label.text = "Timed out";
			yield break;
		}
			
		// Connection has failed
		if (Input.location.status == LocationServiceStatus.Failed) {
			distance_label.text = "Unable to determine device location";
			yield break;
		} else {
			long1 = long2 = Input.location.lastData.longitude;
			lat1 = lat2 = Input.location.lastData.latitude;

			// Access granted and location value could be retrieved
			// distance_label.text = "Location: " + Input.location.lastData.latitude + " " +
			// Input.location.lastData.longitude + " " +
			// Input.location.lastData.altitude;

		}

		// Stop service if there is no need to query location updates continuously
		//Input.location.Stop ();
	}


	/// <summary>
	/// Calculate the distance between two geo coordinates.
	/// </summary>
	/// <returns>Distance traveled in km.</returns>
	/// <param name="latitude1">Latitude1.</param>
	/// <param name="longitude1">Longitude1.</param>
	/// <param name="latitude2">Latitude2.</param>
	/// <param name="longitude2">Longitude2.</param>
	public double CalculateDistance (double latitude1, double longitude1, double latitude2, double longitude2)
	{
		double radiansOverDegrees = (Math.PI / 180.0);
		double R = 6371;	// Earth radius in km

		double radiansLat1 = latitude1 * radiansOverDegrees;
		double radiansLong1 = longitude1 * radiansOverDegrees;

		double radiansLat2 = latitude2 * radiansOverDegrees;
		double radiansLong2 = longitude2 * radiansOverDegrees;

		double dLat = radiansLat2 - radiansLat1;
		double dLong = radiansLong2 - radiansLong1;

		double a = Math.Sin (dLat / 2) * Math.Sin (dLat / 2) +
		           Math.Sin (dLong / 2) * Math.Sin (dLong / 2) * Math.Cos (radiansLat1) * Math.Cos (radiansLat2);
		double c = 2 * Math.Atan2 (Math.Sqrt (a), Math.Sqrt (1 - a));
		double d = R * c;

		return d;
	}



}