This document discusses various plotting tools in Matlab, including: - The plot and stem functions for plotting data values against their index or specified x-values. - Tools for labeling axes, titles, legends, and setting axis properties. - The subplot function for dividing the figure window into multiple plots. - Functions for turning the grid on/off and holding plots. - Examples of simple 2D and 3D function plots.

1. Matlab: Graph Plots

2. Tools for plottingplot- plot(y) plots the values in vector y versus their index. plot(x,y) plots the values in vector y versus x. The plot function produces a piecewise linear graph between its data values. With enough data points it looks continuous.stem- Using stem(y) the data sequence y is plotted as stems from the x-axis terminated with circles for the data values. stem(x,y) plots the data sequence y at the values specified in x.

3. Tools for plottingxlabel('string') - Labels the x-axis with string.ylabel('string') - Labels the y-axis with string.title('string') - Gives the plot the title string.

4. Tools for plottinghold on / off - Normally hold is off. This means that the plot command replaces the current plot with the new one. To add a new plot to an existing graph use hold on. If you want to overwrite the current plot again, use hold off.legend('plot1','plot2',...,'plot N') - The legend command provides an easy way to identify individual plots when there are more than one per figure.axis([xminxmaxyminymax])- Use the axis command to set the axis as you wish.

5. Tools for plottingsubplot(m,n,p) -Divides the figure window into m rows, n columns and selects the pp'th subplot as the current plot, e.g subplot(2,1,1) divides the figure in two and selects the upper part. subplot(2,1,2) selects the lower part.grid on/off - This command adds or removes a rectangular grid to your plot.

6. Graph ComponentsThe following picture shows the basic components of a typical graph.

7. 2-D plottingTo plot the function:y = x2 for x 2 [-2; 2].x = -2:0.2:2;

8. y = x.^2;

9. figure(1);

10. plot(x,y);

11. xlabel('x');

12. ylabel('y=x^2');

13. title('Simple plot');

14. figure(2);

15. stem(x,y);

16. xlabel('x');

17. ylabel('y=x^2');

18. title('Simple stem plot');2-D plottingx = -3:0.2:3; y1 = -x.^2; y2 = x.^2;

19. subplot(2,1,1);

20. plot(x,y1);

21. xlabel('x'); ylabel('y_1=-x^2');

22. gridon;

23. subplot(2,1,2);

24. plot(x,y2);

25. xlabel('x');

26. ylabel('y_2=x^2');2-D plottingt = 0:pi/20:2*pi;

27. y = exp(sin(t));

28. plotyy(t,y,t,y,'plot','stem')

29. xlabel('X Axis')

30. ylabel('Plot Y Axis')

31. title('Two Y Axes')3-D Graphics[x,y] = meshgrid(-3:.1:3);

32. z = x.^2+y.^2;

33. mesh(x,y,z);

34. xlabel('x');

35. ylabel('y');

36. zlabel('z=x^2+y^2');Visit more self help tutorialsPick a tutorial of your choice and browse through it at your own pace.The tutorials section is free, self-guiding and will not involve any additional support.Visit us at www.dataminingtools.net