private void DisplayMap_Load(object sender, EventArgs e)
        {
            MyLineShape a = new MyLineShape("LINESTRING(-181 0,0 0)");
            var b = a.GetLength(GeographyUnit.DecimalDegree, DistanceUnit.Kilometer);
        }

        class MyLineShape : LineShape
        {
            public MyLineShape(string WKT)
                : base(WKT)
            { }

            protected override double GetLengthCore(GeographyUnit shapeUnit, DistanceUnit returningUnit)
            {
                double X = this.GetBoundingBox().UpperLeftPoint.X;
                if (shapeUnit == GeographyUnit.DecimalDegree && X < -180)
                {
                    LineShape line = this.CloneDeep() as LineShape;
                    line.TranslateByOffset(-180 - X, 0);
                    return line.GetLength(shapeUnit, returningUnit);
                }
                else
                { return base.GetLengthCore(shapeUnit, returningUnit); }
            }
        }