/// <summary>
/// Init
/// </summary>
private void initSpeedMeasurement()
{
this.speedTimer = new DispatcherTimer();
this.speedTimer.Interval = TimeSpan.FromMilliseconds(333);
this.speedTimer.Tick += delegate
{
//create geo
var geo = new GeoPosition(this.Current.Latitude, this.Current.Longitude, this.Current.HorizontalAccuracy);
//update history
this.updatePositionHistory(geo);
//speed
this.finalSpeedTo();
};
this.speedTimer.Start();
}
/// <summary>
/// Update position history
/// </summary>
/// <param name="geoPosition"></param>
private void updatePositionHistory(GeoPosition geoPosition)
{
//add position to array
this.gpsLastPositions.Add(geoPosition);
if (this.gpsLastPositions.Count > 9)
{
this.gpsLastPositions.RemoveAt(0);
}
}
/// <summary>
/// Zoom to
/// </summary>
/// <param name="position"></param>
/// <param name="width"></param>
/// <returns></returns>
public double zoomTo(GeoPosition position, double width)
{
var GLOBE_WIDTH = 512;
var west = this.position.Longitude;
var east = position.Longitude;
var angle = east - west;
if (angle < 0) {
angle += 360;
}
return Math.Round(Math.Log(width * 360 / angle / GLOBE_WIDTH) / Math.Log(2, Math.E));
}
/// <summary>
/// Is position accured
/// </summary>
/// <param name="geoCoordinate"></param>
/// <param name="accuracy"></param>
/// <returns></returns>
private bool isPositionAccured(GeoPosition geoCoordinate, double accuracy)
{
return geoCoordinate.Accuracy <= accuracy;
}
/// <summary>
/// Calculate middle point to position
/// </summary>
/// <param name="position"></param>
/// <returns></returns>
public GeoPosition middlePointTo(GeoPosition position)
{
var deltaLatitude = GeoMath.ToRad(this.position.Latitude - position.Latitude);
var deltaLongitude = GeoMath.ToRad(this.position.Longitude - position.Longitude);
var p2Lat = GeoMath.ToRad(this.position.Latitude);
var p1Lat = GeoMath.ToRad(position.Latitude);
var p1Lon = GeoMath.ToRad(position.Longitude);
var Bx = Math.Cos(p2Lat) * Math.Cos(deltaLongitude);
var By = Math.Cos(p2Lat) * Math.Sin(deltaLongitude);
var lat3 = Math.Atan2(Math.Sin(p1Lat) + Math.Sin(p2Lat), Math.Sqrt((Math.Cos(p1Lat) + Bx) * (Math.Cos(p1Lat) + Bx) + By * By));
var lon3 = p1Lon + Math.Atan2(By, Math.Cos(p1Lat) + Bx);
return new GeoPosition(GeoMath.ToDegrees(lat3), GeoMath.ToDegrees(lon3), position.Accuracy);
}
/// <summary>
/// Calculate final bearing to position
/// </summary>
/// <param name="position"></param>
/// <returns></returns>
public double finalBearingTo(GeoPosition position)
{
var lat1 = GeoMath.ToRad(position.Latitude);
var lat2 = GeoMath.ToRad(this.position.Latitude);
var dLon = GeoMath.ToRad(this.position.Longitude - position.Longitude);
var y = Math.Sin(dLon) * Math.Cos(lat2);
var x = Math.Cos(lat1) * Math.Sin(lat2) - Math.Sin(lat1) * Math.Cos(lat2) * Math.Cos(dLon);
var brng = Math.Atan2(y, x);
return (GeoMath.ToDegrees(brng) + 180) % 360;
}
/// <summary>
/// New instance of geo calculation calss
/// </summary>
/// <param name="poition"></param>
public Geo(GeoPosition poition)
{
this.position = poition;
}
/// <summary>
/// Return ditance to position
/// </summary>
/// <param name="position"></param>
/// <returns>Distance in KM</returns>
public double distanceTo(GeoPosition position)
{
var R = RADIUS;
var lat1 = GeoMath.ToRad(this.position.Latitude);
var lon1 = GeoMath.ToRad(this.position.Longitude);
var lat2 = GeoMath.ToRad(position.Latitude);
var lon2 = GeoMath.ToRad(position.Longitude);
var dLat = lat2 - lat1;
var dLon = lon2 - lon1;
var a = Math.Sin(dLat/2) * Math.Sin(dLat/2) + Math.Cos(lat1) * Math.Cos(lat2) * Math.Sin(dLon/2) * Math.Sin(dLon/2);
var c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1-a));
return R * c;
}
/// <summary>
/// Get nearest point
/// </summary>
/// <param name="point"></param>
/// <param name="positions"></param>
/// <param name="current"></param>
/// <param name="start"></param>
/// <returns></returns>
public static Double GetNearest(GeoPosition point, List<GeoPosition> positions, out int current, int start = 0)
{
Double distance = Double.MaxValue;
int max = positions.Count;
Geo geo = new Geo(point);
for (var i = start; i < max; i++)
{
var d = geo.distanceTo(positions[i]);
//next distance is bigger
if (d > distance)
{
current = i - 1;
return distance;
}
//distance is smaller
if (d < distance)
{
distance = d;
}
//reset
if (start > 0 && i == positions.Count - 1)
{
start = 0;
i = 0;
max = start;
}
}
//not found
current = 0;
return distance;
}