Determines whether the GPS longitude and latitude are in the circle, polygon, or rectangle.

Class relationship
{
Static void main (string [] ARGs)
{
// Vector2d point1 = new vector2d (39.909209536859834, 116.3225715637207); // in
Vector2d point1 = new vector2d (39.901045, 116.415596); // out
Vector2d cpoint = new vector2d (39.909209536859834, 116.3225715637207 );
Console. writeline ("Whether the vertex is in the circle:" + whether the vertex is in the circle (cpoint, 8000, point1 ));
Console. writeline ("Whether the vertex is in the circle:" + whether the vertex is in the circle (cpoint, new vector2d (39.901045, 116.415596), point1 ));

// Vector2d point2 = new vector2d (39.924745, 116.379204); // in
Vector2d point2 = new vector2d (39.928695, 116.546059); // out
Vector2d pointa = new vector2d (39.913423004886866, 116.36890411376953 );
Vector2d pointb = new vector2d (39.93450133090293, 116.38727188110351 );
Console. writeline ("Whether the vertex is in the rectangle:" + whether the vertex is in the rectangle (pointa, pointb, point2 ));

Vector2d point3 = new vector2d (39.957649, 116.376801); // in
// Vector2d point3 = new vector2d (39.919216, 116.2817); // out
List <vector2d> polygon = new list <vector2d> ();
Polygon. Add (New vector2d (39.909209536859834, 116.3225715637207 ));
Polygon. Add (New vector2d (39.95920953685983, 116.3725715637207 ));
Polygon. Add (New vector2d (39.95920953685983, 116.42257156372072 ));
Polygon. Add (New vector2d (39.909209536859834, 116.4725715637207 ));
Polygon. Add (New vector2d (39.85920953685984, 116.42257156372072 ));
Polygon. Add (New vector2d (39.85920953685984, 116.3725715637207 ));
Console. writeline ("Whether the vertex is in the polygon:" + whether the vertex is in the polygon (point3, polygon ));

Console. Readline ();
}

///

// whether the vertex is in the circle (the vertex is also considered in the circle on the edge)
///
/// Center Coordinate
/// circle radius
// current vertex
//
whether the public static bool point is in the circle (vector2d cpoint, double cradius, vector2d point)
{< br> var d1 = distance (cpoint. lat, cpoint. lon, point. lat, point. lon);
double distance = math. SQRT (math. pow (math. ABS (point. x-cpoint. x), 2) + math. pow (math. ABS (point. y-cpoint. y), 2);
return distance <= cradius;
}

Private Static double distance (double lon1, double LAT1, double lon2, double LAT2)
{
Double R = 6378137; // Earth radius
LAT1 = LAT1 * Math. PI/180.0;
LAT2 = LAT2 * Math. PI/180.0;
Double SA2 = math. Sin (LAT1-LAT2)/2.0 );
Double sb2 = math. Sin (lon1-lon2) * Math. PI/180.0)/2.0 );
Return 2 * r * Math. asin (math. SQRT (SA2 * SA2 + math. Cos (LAT1) * Math. Cos (LAT2) * sb2 * sb2 ));
}

/// <Summary>
/// Whether the vertex is in the circle (it is also considered in the circle on the edge)
/// </Summary>
/// <Param name = "cpoint"> coordinates of the center </param>
/// <Param name = "onpoint"> coordinates on the circular edge </param>
/// <Param name = "point"> current vertex </param>
/// <Returns> </returns>
Whether the public static bool point is in the circle (vector2d cpoint, vector2d onpoint, vector2d point)
{
Double cradius = distance (cpoint. Lat, cpoint. Lon, onpoint. Lat, onpoint. Lon );
Double distance = distance (cpoint. Lat, cpoint. Lon, point. Lat, point. Lon );
Return distance <= cradius;
}

///

// determines whether the vertex is inside the polygon (or inside the polygon)
///
/// current vertex
/// polygon Points
//
whether the public static bool point is within the polygon (vector2d point, list polygon)
{< br> var res = smath. calcpointpolygonrelation (point, polygon);
return res! = Pointpolygonrelation. outofpolygon;
}

///

// whether the vertex is in the rectangle
///
/// diagonal upper point A
// diagonal upper point B
// current vertex
//
whether the public static bool vertex is in a rectangle (vector2d pointa, vector2d pointb, vector2d point)
{< br> List polygon = new list ();
polygon. add (pointa);
polygon. add (New vector2d (PO INTA. x, pointb. y);
polygon. add (pointb);
polygon. add (New vector2d (pointb. x, pointa. y);
var res = smath. calcpointpolygonrelation (point, polygon);
return res! = Pointpolygonrelation. outofpolygon;
}< BR >}