How to draw circle on the MAP using GMAP.NET in C#

Question

I am using GMAP.NET in c#. I am able to display the map on the form, now i am trying to draw a CIRCLE mouse by clicking on a certian point, keeping the left mouse button an

Answer 1

   private void CreateCircle(Double lat, Double lon, double radius, int ColorIndex)
    {
        PointLatLng point = new PointLatLng(lat, lon);
        int segments = 1080;

        List gpollist = new List();

        for (int i = 0; i < segments; i++)
        {
            gpollist.Add(FindPointAtDistanceFrom(point, i*(Math.PI/180), radius / 1000));
        }

        GMapPolygon polygon = new GMapPolygon(gpollist, "Circle");
        switch (ColorIndex) {

            case 1:
                polygon.Fill = new SolidBrush(Color.FromArgb(80, Color.Red));
                break;
            case 2:
                polygon.Fill = new SolidBrush(Color.FromArgb(80, Color.Orange));
                break;
            case 3:
                polygon.Fill = new SolidBrush(Color.FromArgb(20, Color.Aqua));
                break;
            default:
                MessageBox.Show("No search zone found!");
                break;
        }


        polygon.Stroke = new Pen(Color.Red, 1);
        markers.Polygons.Add(polygon);
        gMapCtl.Overlays.Add(markers);
    }


    public static GMap.NET.PointLatLng FindPointAtDistanceFrom(GMap.NET.PointLatLng startPoint, double initialBearingRadians, double distanceKilometres)
    {
        const double radiusEarthKilometres = 6371.01;
        var distRatio = distanceKilometres / radiusEarthKilometres;
        var distRatioSine = Math.Sin(distRatio);
        var distRatioCosine = Math.Cos(distRatio);

        var startLatRad = DegreesToRadians(startPoint.Lat);
        var startLonRad = DegreesToRadians(startPoint.Lng);

        var startLatCos = Math.Cos(startLatRad);
        var startLatSin = Math.Sin(startLatRad);

        var endLatRads = Math.Asin((startLatSin * distRatioCosine) + (startLatCos * distRatioSine * Math.Cos(initialBearingRadians)));
        var endLonRads = startLonRad + Math.Atan2(Math.Sin(initialBearingRadians) * distRatioSine * startLatCos,distRatioCosine - startLatSin * Math.Sin(endLatRads));

        return new GMap.NET.PointLatLng(RadiansToDegrees(endLatRads), RadiansToDegrees(endLonRads));
    }

    public static double DegreesToRadians(double degrees)
    {
        const double degToRadFactor = Math.PI/180;
        return degrees * degToRadFactor;
    }

    public static double RadiansToDegrees(double radians)
    {
        const double radToDegFactor = 180/Math.PI;
        return radians * radToDegFactor;
    }



    public static double DistanceTwoPoint(double startLat, double startLong, double endLat, double endLong) {

        var startPoint = new GeoCoordinate(startLat, startLong);
        var endPoint = new GeoCoordinate(endLat, endLong);

        return startPoint.GetDistanceTo(endPoint);
    }