Plotting a hysteresis loop with jFreeChart

Question

I need to draw hysteresis loops and then calculate the area closed within the loop. I am using jFreeChart.

consider the following data:

 hyst[0]=0;
       hyst[1]=0;
       hyst[2]=0.0098;
       hyst[3]=0.0196;
       hyst[4]=0.0489;
       hyst[5]=0.0879;
       hyst[6]=0.0684;
       hyst[7]=0.0489;
       hyst[8]=0.0196;
       hyst[9]=0.0098;
       hyst[10]=0;
       hyst[11]=0;
       hyst[12]=0;
       hyst[13]=0;
       hyst[14]=0;
       hyst[15]=-0.0195;
       hyst[16]=-0.0488;
       hyst[17]=-0.0391;
       hyst[18]=-0.0195;
       hyst[19]=0;
       hyst[20]=0;

When I try :

   public void plotHysteresis()
   {
       int j=0;
       int i=0;
       XYSeries series1 = new XYSeries("Before Treatment");
      // DefaultCategoryDataset series1 = new DefaultCategoryDataset();
       for(i=0;i<6;i++)
       {    
        series1.add(j,hyst[i]);
        logTextArea.append(Integer.toString(j) +" : " +Double.toString(hyst[i])+"\n");
        j=j+5;
       }
       j=j-5; 
       for(;i<11;i++)
       {
        j=j-5;   
        series1.add(j,hyst[i]);
        logTextArea.append(Integer.toString(j) +" : " +Double.toString(hyst[i])+"\n");
       }
        for(;i<16;i++)
       {
        j=j-5;   
        series1.add(j,hyst[i]);
        logTextArea.append(Integer.toString(j) +" : " +Double.toString(hyst[i])+"\n");
       }
           for(;i<21;i++)
       {
        j=j+5;   
        series1.add(j,hyst[i]);
        logTextArea.append(Integer.toString(j) +" : " +Double.toString(hyst[i])+"\n");
       }

    XYSeriesCollection dataset = new XYSeriesCollection();
    dataset.addSeries(series1);

    JFreeChart chart = ChartFactory.createXYAreaChart(
"Hysteresis Plot", // chart title
"Pounds (lb)", // x axis label
"Distance (inches)", // y axis label
dataset, // data
PlotOrientation.VERTICAL,
true, // include legend
true, // tooltips
false // urls
);
    chart.setBackgroundPaint(Color.white);

    ChartPanel frame = new ChartPanel(chart);
    frame.setVisible(true);
    frame.setSize(plotPanel.getWidth(),plotPanel.getHeight());
    plotPanel.add(frame);
    plotPanel.repaint();
   }

It gives me below result:

If I use :

 JFreeChart chart = ChartFactory.createXYLineChart(
"Hysteresis Plot", // chart title
"Pounds (lb)", // x axis label
"Distance (inches)", // y axis label
dataset, // data
PlotOrientation.VERTICAL,
true, // include legend
true, // tooltips
false // urls
);

I gives:

I need a hysteresis plot that looks like:

I guess the difference is the way points are being connected. Please guide how to obtained the desired hysteresis loop with jFreeChart and then how to calculate area enclosed.

Thanks

Wouldbe

You could plot two XYLine: one for the higher line and one for the lower one. – Twit

@Twit Is there any other solution, instead of using two lines. I need to plot many such hysteresis plots for different readings obtained for hyst[23] and need to superimpose them on the same graph and compare the enclosed area changes.. – Wouldbe

Some ideas for area are mentioned here. – Antibiotic

Answer 1

How can I change the line color as well the symbols representing the data points. I want all of them to be uniform.

It appears you've settled on JFreeChart for your view. Synthesizing a few other comments,

• You can make the colors and shapes of your several series homogeneous by providing a DrawingSupplier, as suggested here and shown here.

• You can combine the series into a GeneralPath and estimate the area as outlined here.

Antibiotic