C# Circles With kml in Google Earth

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C#

Hello Everybody,


i need a little help from you, im trying to draw a circle around a point (lat/long) in Google Earth, i found some php examples of a circle generator where they use a formula to get te linestring points for the circle by radius. in the php example, it draws a perfect circle but i need the formula implemented in a c# winform app. so i adapted it, and its draws, but it dras an elipse :confused: not a circle.

here is my code:

  public void Save()
        {
            string FullFilePath = _KMLFilePath + _KMLFileName;

            XmlTextWriter xtr = new XmlTextWriter(FullFilePath, Encoding.UTF8);

            xtr.WriteStartDocument();

            xtr.WriteStartElement("kml");//start kml
            xtr.WriteStartAttribute("xmlns");
            xtr.WriteString("http://earth.google.com/kml/2.2");
            xtr.WriteEndAttribute();
            //xtr.WriteString();

            {
                xtr.WriteStartElement("Document");//start document
                {
                    
                        xtr.WriteStartElement("name");//start name
                        {
                            xtr.WriteString("Posiciones Fijas");
                        }
                        xtr.WriteEndElement();//end name


                        #region calcular cada punto con su circulo
                        for (int i = 0; i < _Coords.Count; i++)
                        {
                            xtr.WriteStartElement("Placemark");//start placemark
                            {
                                xtr.WriteStartElement("name");//start name
                                {
                                    xtr.WriteString(_Names[i]);
                                }
                                xtr.WriteEndElement();//end name
                                xtr.WriteStartElement("description");//start description
                                {
                                    xtr.WriteString(_Description[i]);
                                }
                                xtr.WriteEndElement();//end description
                                xtr.WriteStartElement("visibility");//start vis
                                {
                                    xtr.WriteString("1");
                                }
                                xtr.WriteEndElement();//end vis
                                xtr.WriteStartElement("Style");//start Style
                                {

                                    xtr.WriteStartElement("geomColor");//start
                                    {
                                        xtr.WriteString("FFffffFF");
                                    }
                                    xtr.WriteEndElement();//end
                                    xtr.WriteStartElement("geomScale");//start
                                    {
                                        xtr.WriteString("1");
                                    }
                                    xtr.WriteEndElement();//end
                                }
                                xtr.WriteEndElement();//end Style
                                xtr.WriteStartElement("LineString");
                                {
                                    xtr.WriteStartElement("coordinates");
                                    {
                                        #region calcular circulo
                                        double Latitud = deg2rad(double.Parse(_Coords[i].Latitude.Replace(".", ",")));
                                        double Longitud = deg2rad(double.Parse(_Coords[i].Longitude.Replace(".", ",")));
                                        double d_rad = (_radius / 6378137);
                                        for (int j = 0; j <= 360; j++)
                                        {
                                            double radial = (Math.PI*j) / 180;
                                            double lat_rad = Math.Asin((Math.Sin(Latitud) * Math.Cos(d_rad)) + (Math.Cos(Latitud) * Math.Sin(d_rad) * Math.Cos(radial)));
                                            double dlon_rad = Math.Atan2(Math.Sin(radial) * Math.Sin(d_rad) * Math.Cos(Latitud), Math.Cos(d_rad) - Math.Sin(Latitud) * Math.Sin(lat_rad));
                                            double lon_rad = ((Longitud + dlon_rad + Math.PI) %( 2 * Math.PI)) - Math.PI;
                                            xtr.WriteString(rad2deg(lat_rad).ToString().Replace(",", ".") + ", " + rad2deg(lon_rad).ToString().Replace(",", ".") + ", 0 ");
                                        }
                                        #endregion
                                    }
                                    xtr.WriteEndElement();//end coordinates
                                }
                                xtr.WriteEndElement();//end linestring
                            }
                            xtr.WriteEndElement();//end placemark
                        }
                        #endregion
                
                }
                xtr.WriteEndElement(); //end document
            }
            xtr.WriteEndElement();//end kml

            xtr.WriteEndDocument();

            xtr.Close();
            
        }


private double deg2rad(double deg)
       {
           return Math.PI* deg / 180;
       }
       private double rad2deg(double rad)
       {
           return rad *(180 / Math.PI);
       }

i dont know what exactly is going wrong

can anybody help me im a little bit blind,

The original source code for php is located here:

http://dev.bt23.org/keyhole/circlegen/output.phps[^]