using System.Collections.Generic; using System.Linq; namespace CoordinateSharp { /// /// Geo Fence class. It helps to check if points/coordinates are inside a polygon, /// Next to a polyline, and counting... /// public class GeoFence { #region Fields private List _points = new List(); #endregion /// /// Prepare GeoFence with a list of points /// /// List of points public GeoFence(List points) { _points = points; } /// /// Prepare Geofence with a list of coordinates /// /// List of coordinates public GeoFence(List coordinates) { foreach (var c in coordinates) { _points.Add(new Point { Latitude = c.Latitude.ToDouble(), Longitude = c.Longitude.ToDouble() }); } } #region Utils private Coordinate ClosestPointOnSegment(Point a, Point b, Coordinate p) { var d = new Point { Longitude = b.Longitude - a.Longitude, Latitude = b.Latitude - a.Latitude, }; double number = (p.Longitude.ToDouble() - a.Longitude) * d.Longitude + (p.Latitude.ToDouble() - a.Latitude) * d.Latitude; if (number <= 0.0) return new Coordinate(a.Latitude, a.Longitude); double denom = d.Longitude * d.Longitude + d.Latitude * d.Latitude; if (number >= denom) return new Coordinate(b.Latitude, b.Longitude); return new Coordinate(a.Latitude + (number / denom) * d.Latitude, a.Longitude + (number / denom) * d.Longitude); } #endregion /// /// The function will return true if the point x,y is inside the polygon, or /// false if it is not. If the point is exactly on the edge of the polygon, /// then the function may return true or false. /// /// The point to test /// bool public bool IsPointInPolygon(Coordinate point) { if (point == null) return false; double latitude = point.Latitude.ToDouble(); double longitude = point.Longitude.ToDouble(); int sides = _points.Count; int j = sides - 1; bool pointStatus = false; for (int i = 0; i < sides; i++) { if (_points[i].Latitude < latitude && _points[j].Latitude >= latitude || _points[j].Latitude < latitude && _points[i].Latitude >= latitude) { if (_points[i].Longitude + (latitude - _points[i].Latitude) / (_points[j].Latitude - _points[i].Latitude) * (_points[j].Longitude - _points[i].Longitude) < longitude) { pointStatus = !pointStatus; } } j = i; } return pointStatus; } /// /// The function will return true if the point x,y is next the given range of /// the polyline, or false if it is not. /// /// The point to test /// The range in meters /// bool public bool IsPointInRangeOfLine(Coordinate point, double range) { if (point == null) return false; for (int i = 0; i < _points.Count - 1; i++) { Coordinate c = ClosestPointOnSegment(_points[i], _points[i + 1], point); if (c.Get_Distance_From_Coordinate(point).Meters <= range) return true; } return false; } /// /// The function will return true if the point x,y is next the given range of /// the polyline, or false if it is not. /// /// The point to test /// The range is a distance object /// bool public bool IsPointInRangeOfLine(Coordinate point, Distance range) { if (point == null || range == null) return false; return IsPointInRangeOfLine(point, range.Meters); } /// /// This class is a help class to simplify GeoFence calculus /// public class Point { /// /// Initialize empty point /// public Point() { } /// /// Initialize point with defined Latitude and Longitude /// /// Latitude (signed) /// Longitude (signed) public Point(double lat, double lng) { Latitude = lat; Longitude = lng; } /// /// The longitude in degrees /// public double Longitude; /// /// The latitude in degrees /// public double Latitude; } } }