private void PlotPanelPaint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;

            g.SmoothingMode = SmoothingMode.AntiAlias;

            if (dc.ChartType == DrawChart.ChartTypeEnum.XYColor ||
                dc.ChartType == DrawChart.ChartTypeEnum.Contour ||
                dc.ChartType == DrawChart.ChartTypeEnum.FillContour)
            {
                cs2d.AddChartStyle2D(g, cs);
                dc.AddChart(g, ds, cs, cs2d);
            }
            else
            {
                cs.Elevation = trkElevation.Value;
                cs.Azimuth   = trkAzimuth.Value;
                cf.Exp4D(ds, cs);
                cs.AddChartStyle(g);
                dc.AddChart(g, ds, cs, cs2d);
            }
        }