C#使用GeoJSON点集合创建类型为ArcGIS Geometry的外接正方形

直接上代码：

        /// <summary>传入一系列的GeoJSON格式的点集，转换得到外包正方形
        /// 
        /// </summary>
        /// <param name="listPoint">GeoJSON格式的点集</param>
        /// <param name="b">可选参数，缓冲距离</param>
        /// <returns></returns>
        public static ESRI.ArcGIS.Geometry.IPolygon CreateEsriPolygon(List<GeoJSON.Net.Geometry.Point> listPoint, double? b = 0.0)
        {
            if (0 >= listPoint.Count)
                return null;

            var firstPoint = listPoint[0].Coordinates;
            double dMinX = firstPoint.X; double dMinY = firstPoint.Y; double dMaxX = firstPoint.X; double dMaxY = firstPoint.Y; double dSumX = 0.00; double dSumY = 0.00;
            foreach (var aPt in listPoint)
            {
                dMinX = aPt.Coordinates.X <= dMinX ? aPt.Coordinates.X : dMinX;
                dMinY = aPt.Coordinates.Y <= dMinY ? aPt.Coordinates.Y : dMinY;
                dMaxX = aPt.Coordinates.X >= dMaxX ? aPt.Coordinates.X : dMaxX;
                dMaxY = aPt.Coordinates.Y >= dMaxY ? aPt.Coordinates.Y : dMaxY;
                dSumX += aPt.Coordinates.X;
                dSumY += aPt.Coordinates.Y;
            }
            double dCenX = dSumX * 100 / listPoint.Count * 0.01;  //正方形中心点X坐标
            double dCenY = dSumY * 100 / listPoint.Count * 0.01;  //正方形中心点Y坐标
            double dHalfLength = (((dMaxX - dMinX) > (dMaxY - dMinY)) ? (dMaxX - dMinX) : (dMaxY - dMinY)) * 0.5;
            dHalfLength += (b.HasValue && (double)b > 0) ? (double)b : 0;  //正方形边长的一半

            ESRI.ArcGIS.Geometry.IPointCollection pPointCol = new ESRI.ArcGIS.Geometry.Polygon();
            pPointCol.AddPoint(CreatePoint(dCenX - dHalfLength, dCenY + dHalfLength));  //左上角点
            pPointCol.AddPoint(CreatePoint(dCenX + dHalfLength, dCenY + dHalfLength));  //右上角点
            pPointCol.AddPoint(CreatePoint(dCenX + dHalfLength, dCenY - dHalfLength));  //右下角点
            pPointCol.AddPoint(CreatePoint(dCenX - dHalfLength, dCenY - dHalfLength));   //左下角点
            pPointCol.AddPoint(CreatePoint(dCenX - dHalfLength, dCenY + dHalfLength));  //左上角点（用于闭合线段）

            return pPointCol as ESRI.ArcGIS.Geometry.IPolygon;
        }