public static double CalculateSpeedKPH(Position previousPosition, Position currentPosition, out double distanceKM, out double timeHours)
{
distanceKM = CalculateDistanceKM(previousPosition, currentPosition);
timeHours = new TimeSpan(currentPosition.Timestamp.Ticks - previousPosition.Timestamp.Ticks).TotalHours;
return distanceKM / timeHours;
}
public PointOfInterest(string name, string type, Position position)
: this()
{
_name = name ?? "";
_type = type ?? "";
_position = position;
}
public override void Stop()
{
lock (_locker)
{
base.Stop();
_previousPosition = null; // reset previous location so it doesn't get used when this probe is restarted.
}
}
public override void Start()
{
lock (_locker)
{
_previousPosition = null; // do this before starting the base-class poller so it doesn't race to grab a stale previous location.
base.Start();
}
}
private GpsReceiver()
{
_desiredAccuracyMeters = 10;
_readingIsComing = false;
_readingWait = new ManualResetEvent(false);
_reading = null;
_readingTimeoutMS = 120000;
_minimumTimeHintMS = 5000;
}
private GpsReceiver()
{
_desiredAccuracyMeters = 50; // setting this too low appears to result in very delayed GPS fixes.
_readingIsComing = false;
_readingWait = new ManualResetEvent(false);
_reading = null;
_readingTimeoutMS = 120000;
_minimumTimeHintMS = 5000;
}
public ProductsMapScreen(Position position, IEnumerable<Product> products)
: base("ProductsMapScreen", null)
{
this.position = position;
this.products = products;
TabBarItem = new UITabBarItem
{
Title = "Map",
Image = UIImage.FromFile("Images/globe_64.png")
};
}
public void OnLocationChanged( Location location )
{
if(location.Provider != activeProvider)
{
if(activeProvider != null && manager.IsProviderEnabled( activeProvider ))
{
LocationProvider pr = manager.GetProvider( location.Provider );
TimeSpan lapsed = GetTimeSpan( location.Time ) - GetTimeSpan( lastLocation.Time );
if(pr.Accuracy > manager.GetProvider( activeProvider ).Accuracy && lapsed < timePeriod.Add( timePeriod ))
{
location.Dispose();
return;
}
}
activeProvider = location.Provider;
}
var previous = Interlocked.Exchange( ref lastLocation, location );
if(previous != null)
{
previous.Dispose();
}
var p = new Position();
if(location.HasAccuracy)
{
p.Accuracy = location.Accuracy;
}
if(location.HasAltitude)
{
p.Altitude = location.Altitude;
}
if(location.HasBearing)
{
p.Heading = location.Bearing;
}
if(location.HasSpeed)
{
p.Speed = location.Speed;
}
p.Longitude = location.Longitude;
p.Latitude = location.Latitude;
p.Timestamp = Geolocator.GetTimestamp( location );
var changed = PositionChanged;
if(changed != null)
{
changed( this, new PositionEventArgs( p ) );
}
}
private static Position ToFormsPosition(Xamarin.Geolocation.Position pos)
{
return(new Position {
Accuracy = pos.Accuracy,
Altitude = pos.Altitude,
AltitudeAccuracy = pos.AltitudeAccuracy,
Heading = pos.Heading,
Latitude = pos.Latitude,
Longitude = pos.Longitude,
Speed = pos.Speed,
Timestamp = pos.Timestamp
});
}
public List<SpotViewModel> FindMiningSpots(Position position)
{
List<SpotViewModel> spots = new List<SpotViewModel>();
foreach (var item in GetSpots())
{
var spotVM = new SpotViewModel(item, position.Latitude, position.Longitude);
if (spotVM.Distance < 0.25)
{
spots.Add(spotVM);
}
}
return spots;
}
public Position (Position position)
{
if (position == null)
throw new ArgumentNullException ("position");
Timestamp = position.Timestamp;
Latitude = position.Latitude;
Longitude = position.Longitude;
Altitude = position.Altitude;
AltitudeAccuracy = position.AltitudeAccuracy;
Accuracy = position.Accuracy;
Heading = position.Heading;
Speed = position.Speed;
}
public SpeedDatum(DateTimeOffset timestamp, Position previousPosition, Position currentPosition)
: base(timestamp, 0)
{
double distanceKM;
double timeHours;
_kph = SpeedDatum.CalculateSpeedKPH(previousPosition, currentPosition, out distanceKM, out timeHours);
if (previousPosition.Accuracy >= 0 && currentPosition.Accuracy >= 0)
{
double maximumDistanceKM = distanceKM + previousPosition.Accuracy / 1000f + currentPosition.Accuracy / 1000f;
double maximumSpeedKPH = maximumDistanceKM / timeHours;
Accuracy = (float)(maximumSpeedKPH - _kph);
}
}
async void GetPosition()
{
try
{
locator = new Geolocator{DesiredAccuracy =50};
if ( locator.IsListening != true )
locator.StartListening(minTime: 1000, minDistance: 0);
position = await locator.GetPositionAsync (timeout: 20000);
}
catch ( Exception e)
{
}
}
/// <summary>
/// Calculates distance (KM) given two lat-lon positions (http://www.movable-type.co.uk/scripts/latlong.html)
/// </summary>
/// <returns>Distance in KM.</returns>
/// <param name="previousPosition">Previous position.</param>
/// <param name="currentPosition">Current position.</param>
public static double CalculateDistanceKM(Position previousPosition, Position currentPosition)
{
double φ1 = DegreesToRadians(previousPosition.Latitude);
double φ2 = DegreesToRadians(currentPosition.Latitude);
double Δφ = DegreesToRadians(currentPosition.Latitude - previousPosition.Latitude);
double Δλ = DegreesToRadians(currentPosition.Longitude - previousPosition.Longitude);
double a = Math.Pow(Math.Sin(Δφ / 2), 2) +
Math.Cos(φ1) *
Math.Cos(φ2) *
Math.Pow(Math.Sin(Δλ / 2), 2);
double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
return 6371 * c;
}
public ListeningSpeedProbe()
{
_positionChangedHandler = (o, e) =>
{
lock (_locker)
{
SensusServiceHelper.Get().Logger.Log("Received position change notification.", LoggingLevel.Verbose, GetType());
if (_previousPosition != null && e.Position != null && e.Position.Timestamp != _previousPosition.Timestamp)
StoreDatum(new SpeedDatum(e.Position.Timestamp, _previousPosition, e.Position));
if (e.Position != null)
_previousPosition = e.Position;
}
};
}
private async void GetPositionHandler (object state)
{
try
{
Position p = await this.geolocator.GetPositionAsync (10000);
CurrentPosition = p;
}
catch (GeolocationException ex)
{
Status = "Error: (" + ex.Error + ") " + ex.Message;
}
catch (TaskCanceledException cex)
{
Status = "Canceled";
}
}
public IEnumerable<Product> GetProductsNear(Position position)
{
var products = Enumerable.Empty<Product>();
Console.WriteLine("Fetching products near: {0} lat, {1} long", position.Latitude, position.Longitude);
var request = WebRequest.Create(CoordinatesUrl.FormatWith(position.Latitude, position.Longitude));
using (var response = request.GetResponse())
{
//BUG: MT 5.3.2 see http://docs.xamarin.com/ios/troubleshooting#System.ExecutionEngineException.3a_Attempting_to_JIT_compile_method_(wrapper_managed-to-managed)_Foo.5b.5d.3aSystem.Collections.Generic.ICollection.601.get_Count_()
JsonReader<CLLocationCoordinate2D>.GetParseFn();
try{
products = JsonSerializer.DeserializeFromStream<Product[]>(response.GetResponseStream());
}
catch{ }
}
return products.Where(x => !string.IsNullOrWhiteSpace(x.Url));
}
public ListeningSpeedProbe()
{
_positionChangedHandler = (o, e) =>
{
if (e.Position == null)
return;
lock (_locker)
{
SensusServiceHelper.Get().Logger.Log("Received position change notification.", LoggingLevel.Verbose, GetType());
if (_previousPosition == null)
_previousPosition = e.Position;
else if (e.Position.Timestamp > _previousPosition.Timestamp) // it has happened (rarely) that positions come in out of order...drop any such positions.
{
StoreDatum(new SpeedDatum(e.Position.Timestamp, _previousPosition, e.Position));
_previousPosition = e.Position;
}
}
};
}
double distForPos(Position lhs, Position rhs)
{
return Math.Sqrt(
Math.Pow(rhs.Latitude - lhs.Latitude, 2.0) +
Math.Pow(rhs.Longitude - lhs.Longitude, 2.0));
}
private async void GetPositionHandler (object state)
{
ShowProgress = true;
Status = "Getting location..";
if (!this.geolocator.IsGeolocationEnabled)
{
Status = "Location disabled";
return;
}
try
{
Position p = await this.geolocator.GetPositionAsync (10000, includeHeading: true);
CurrentPosition = p;
Status = "Success";
}
catch (GeolocationException ex)
{
Status = "Error: (" + ex.Error + ") " + ex.Message;
}
catch (TaskCanceledException cex)
{
Status = "Canceled";
}
ShowProgress = false;
}
private void GeolocatorOnPositionChanged (object sender, PositionEventArgs e)
{
CurrentPosition = e.Position;
}
public ProductSearchController(Position position, IEnumerable<Product> products)
{
this.position = position;
this.products = products;
}
void geo_PositionChanged(object sender, PositionEventArgs e)
{
lock (geo)
{
currentPosition = e.Position;
System.Diagnostics.Debug.WriteLine("CURRENT POSITION: " + currentPosition.Latitude.ToString() + ", " + currentPosition.Longitude.ToString());
}
}
private void UpdateLocation()
{
locationManager = new Geolocator (this);
locationManager.PositionChanged += (sender, e) => {
location = e.Position;
locationManager.StopListening ();
};
locationManager.StartListening (0, 0);
}
private void Finish( Location location )
{
var p = new Position();
if(location.HasAccuracy)
{
p.Accuracy = location.Accuracy;
}
if(location.HasAltitude)
{
p.Altitude = location.Altitude;
}
if(location.HasBearing)
{
p.Heading = location.Bearing;
}
if(location.HasSpeed)
{
p.Speed = location.Speed;
}
p.Longitude = location.Longitude;
p.Latitude = location.Latitude;
p.Timestamp = Geolocator.GetTimestamp( location );
if(finishedCallback != null)
{
finishedCallback();
}
completionSource.TrySetResult( p );
}
private void UpdatePosition (CLLocation location)
{
Position p = (this.position == null) ? new Position () : new Position (this.position);
if (location.HorizontalAccuracy > -1)
{
p.Accuracy = location.HorizontalAccuracy;
p.Latitude = location.Coordinate.Latitude;
p.Longitude = location.Coordinate.Longitude;
}
if (location.VerticalAccuracy > -1)
{
p.Altitude = location.Altitude;
p.AltitudeAccuracy = location.VerticalAccuracy;
}
if (location.Speed > -1)
p.Speed = location.Speed;
p.Timestamp = new DateTimeOffset ((DateTime)location.Timestamp);
this.position = p;
OnPositionChanged (new PositionEventArgs (p));
location.Dispose();
}
private void OnUpdatedHeading (object sender, CLHeadingUpdatedEventArgs e)
{
if (e.NewHeading.TrueHeading == -1)
return;
Position p = (this.position == null) ? new Position () : new Position (this.position);
p.Heading = e.NewHeading.TrueHeading;
this.position = p;
OnPositionChanged (new PositionEventArgs (p));
}
public async Task UpdateSpots(Position newPosition){
await Task.Run(() => {
NearSpots = FindMiningSpots(newPosition);
});
}
protected override IEnumerable<Datum> Poll(CancellationToken cancellationToken)
{
lock (_locker)
{
Position currentPosition = GpsReceiver.Get().GetReading(cancellationToken);
Datum[] data = null;
if (_previousPosition == null || currentPosition == null || currentPosition.Timestamp == _previousPosition.Timestamp)
data = new Datum[] { };
else
data = new SpeedDatum[] { new SpeedDatum(currentPosition.Timestamp, _previousPosition, currentPosition) };
if (currentPosition != null)
_previousPosition = currentPosition;
return data;
}
}
/// <summary>
/// Gets a GPS reading, reusing an old one if it isn't too old. Will block the current thread while waiting for a GPS reading. Should not
/// be called from the main / UI thread, since GPS runs on main thread (will deadlock).
/// </summary>
/// <returns>The reading.</returns>
/// <param name="maxReadingAgeForReuseMS">Maximum age of old reading to reuse (milliseconds).</param>
/// <param name="cancellationToken">Cancellation token.</param>
public Position GetReading(int maxReadingAgeForReuseMS, CancellationToken cancellationToken)
{
lock (_locker)
{
// reuse existing reading if it isn't too old
if (_reading != null && maxReadingAgeForReuseMS > 0)
{
double readingAgeMS = (DateTimeOffset.UtcNow - _reading.Timestamp).TotalMilliseconds;
if (readingAgeMS <= maxReadingAgeForReuseMS)
{
SensusServiceHelper.Get().Logger.Log("Reusing previous GPS reading, which is " + readingAgeMS + "ms old (maximum = " + maxReadingAgeForReuseMS + "ms).", LoggingLevel.Verbose, GetType());
return _reading;
}
}
if (_readingIsComing)
SensusServiceHelper.Get().Logger.Log("A GPS reading is coming. Will wait for it.", LoggingLevel.Debug, GetType());
else
{
_readingIsComing = true; // tell any subsequent, concurrent callers that we're taking a reading
_readingWait.Reset(); // make them wait
new Thread(async () =>
{
try
{
SensusServiceHelper.Get().Logger.Log("Taking GPS reading.", LoggingLevel.Debug, GetType());
DateTimeOffset readingStart = DateTimeOffset.UtcNow;
Position newReading = await _locator.GetPositionAsync(timeout: _readingTimeoutMS, cancelToken: cancellationToken);
DateTimeOffset readingEnd = DateTimeOffset.UtcNow;
if (newReading != null)
{
// create copy of new position to keep return references separate, since the same Position object is returned multiple times when a change listener is attached.
_reading = new Position(newReading);
SensusServiceHelper.Get().Logger.Log("GPS reading obtained in " + (readingEnd - readingStart).TotalSeconds + " seconds.", LoggingLevel.Verbose, GetType());
}
}
catch (Exception ex)
{
SensusServiceHelper.Get().Logger.Log("GPS reading failed: " + ex.Message, LoggingLevel.Normal, GetType());
_reading = null;
}
_readingWait.Set(); // tell anyone waiting on the shared reading that it is ready
_readingIsComing = false; // direct any future calls to this method to get their own reading
}).Start();
}
}
_readingWait.WaitOne(_readingTimeoutMS);
if (_reading == null)
SensusServiceHelper.Get().Logger.Log("GPS reading is null.", LoggingLevel.Normal, GetType());
return _reading;
}
private void OnListenerPositionChanged( object sender, PositionEventArgs e )
{
if(!IsListening) // ignore anything that might come in afterwards
{
return;
}
lock(positionSync)
{
lastPosition = e.Position;
var changed = PositionChanged;
if(changed != null)
{
changed( this, e );
}
}
}
