How to plot XYLineChart graph using two arrays: one for x and y coordinates

Question

How to plot line graph using JFreeChart with two arrays: one for x coordinates and the other for y coordinates. I have two functions which gives me two arrays. I want to plot line graph with that arrays is there any possible way that I can do this.

XYSeries series = new XYSeries(" "); 
for(int i=((fIndex-1)*2);i<=((tIndex*2)-1);i+=2)
{
    series.add(xTValue[i],yTValue[i]);
} 
XYSeriesCollection dataset = new XYSeriesCollection(); 
dataset.addSeries(series); 
return dataset;

Can I do this as above code.

If this is not a duplicate, please [edit] your question to include a [mcve] that shows your revised approach. — trashgod, Nov 01 '17 at 23:18

SteveR · Accepted Answer · 2017-12-20T23:22:55.687

You can use

XYSeriesCollection dataset = new XYSeriesCollection();
XYSeries series = new DefaultXYSeries();
series.addSeries(" ", new double[][]{xTValue,yTValue});
dataset.addSeries(series);
JFreeChart chart = ChartFactory.createXYLineChart("My chart title", 
        "my x-axis label", "my y-axis label", dataset);

Alternatively, if you dont specifically need an XYLineChart, then you can do this by subclassing FastScatterPlot (I know you want a line plot, but this is an easy way in - you override the render() method to draw lines!), with something like the following:

public class LinePlot extends FastScatterPlot {
    private float[] x, y;

    public LinePlot(float[] x, float[] y){
        super();
        this.x=x;
        this.y=y;
    }

    @Override
    public void render(final Graphics2D g2, final Rectangle2D dataArea,
        final PlotRenderingInfo info, final CrosshairState crosshairState) {

        // Get the axes
        ValueAxis xAxis = getDomainAxis();
        ValueAxis yAxis = getRangeAxis();

        // Move to the first datapoint
        Path2D line = new Path2D.Double();
        line.moveTo(xAxis.valueToJava2D(x[0], dataArea, RectangleEdge.BOTTOM),
                yAxis.valueToJava2D(y[0], dataArea, RectangleEdge.LEFT));

        for (int i = 1; i<x.length; i++){
            //Draw line to next datapoint
            line.lineTo(aAxis.valueToJava2D(x[i], dataArea, RectangleEdge.BOTTOM),
                    yAxis.valueToJava2D(y[i], dataArea, RectangleEdge.LEFT));
        }
        g2.draw(line);
    }
}

This is a fairly bare-bones implementation - for example no checks that x and y have same number of points, and no addition of colour etc (e.g. g2.setPaint(myPaintColour) or line type (e.g. g2.setStroke(new BasicStroke(1.0f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_MITER, 10.0f, new float[] { 7, 3, 1, 3 }, 0.0f)) would give alternating -•-•-type lines)

I want to plot XYLineChart. but not scatter plot. And i have same number of points in X and Y — user6308908, Nov 02 '17 at 04:40
In that case use `DefaultXYSeries` as follows `XYSeries series = new Default XYSeries(); series.addSeries(" ", new double[][]{xTValue,yTValue});` — SteveR, Nov 02 '17 at 23:21
I am new to JFreeChart please suggest me an example to use DefalutXYSeries — user6308908, Nov 03 '17 at 04:44
OK, in that case, use ```XYSeriesCollection dataset = new XYSeriesCollection(); dataset.addSeries(series); JFreeChart chart = ChartFactory.createXYLineChart("My chart title", "my x-axis label", "my y-axis label", dataset);``` — SteveR, Nov 06 '17 at 13:16
@user6308908 - great - I've updated the answer above to reflect that — SteveR, Dec 20 '17 at 17:30

How to plot XYLineChart graph using two arrays: one for x and y coordinates

1 Answers1