2-D graph problem

I want to make this graph. Anyone can help me for code pls. And legend gives error on this code

x=[6,7,8,9,10,11,12,13,14,15,16,17,18];
y1=[32.3, 32, 31.9, 34.4, 39.8, 44.8, 49.6, 54.4, 58.7, 62.6, 65.3, 66.2, 64.8];
y2=[32.6, 32.3, 32.2, 35.2, 41.2, 46.3, 51.3, 56, 60.4, 64.1, 66.8, 67.4, 65.6];
z=[y1;y2];
a=plotyy(x,y1,x,y2);
hold on
y3=[64, 90, 399, 662, 981, 1220, 1366, 1376, 1284, 1072, 777, 469, 221];
y4=[138.138, 138.138, 138.138, 368.368, 644.644, 690.69, 782.782, 736.736, 782.782, 690.69, 690.69, 552.552, 368.368];
u=[y3;y4];
b=plotyy(x,y3,x,y4);
hold off
title('Solar Energy')
xlabel('Time')
ylabel('Temperature')
ylabel(b(2),'Energy Rate')
legend('Collector input temperature','Collector output temperature','Radiation intensity(W/m^2)','Heat(W)'

[Anusha Sridharan]

[Answers Dev] Restored edits and attachment

Answer 1

[Walter Roberson]

You do

a=plotyy(x,y1,x,y2);
hold on
b=plotyy(x,y3,x,y4);

The x, y1 plots in the current axes of the time, and then a second axes is created to plot x, y2, leaving the first axes as the current axes, with an output in a of the two axes. Then you "hold on". Then you plotyy(x, y3, x, y4) which plots x, y3 in the current axes, which is the same one plotted to for x, y1 . To plot x, y4, plotyy() then creates a new axes, not the same as the second one that was created for x, y2; the current axes and the new axes are stored in b, and the existing current axes is left the current axes. So now a(1) is an axes that has two children, x,y1 and x,y3; a(2) is a second axes with one child, x,y2; b(1) is the same axes as a(1) so there are the same two children for it; b(2) is a third axes with one child, x,y4 .

At this point you call legend() on the current axes, which is the one that has x, y1 and x, y3 in it, and most recently also wrote to axes b(2) . legend() puts the first two entries against x, y1 and x, y3, and seeing b(2) recently written to, manages to put the third entry against b(2) . But it has lost track of the fact that it wrote to a(2) and doesn't know what to do with the fourth legend entry.

I recommend that you do not use plotyy the second time: that you do something like

hold(a(1), 'on')
hold(a(2), 'on')
plot(a(1), x, y3)
plot(a(2), x, y4)

and that then you are careful about the order of the legend entries.

[john parker]

Sir can u give me full code?

[Walter Roberson]

I do not know which legend you intend to associate with which line.

[Walter Roberson]

I copied and executed your code, and then I took the time to write up a detailed explanation of why you see what you see, and I made a recommendation as to how you can fix the problem. You made no obvious attempt to think about what I had written, and asked for full replacement code. I cannot provide full replacement code at this time because I do not know which variable (y1, y2, y3, y4) is goes with which legend entry.

[Walter Roberson]

t=[6,7,8,9,10,11,12,13,14,15,16,17,18];
cintemp=[32.3, 32, 31.9, 34.4, 39.8, 44.8, 49.6, 54.4, 58.7, 62.6, 65.3, 66.2, 64.8];
couttemp=[32.6, 32.3, 32.2, 35.2, 41.2, 46.3, 51.3, 56, 60.4, 64.1, 66.8, 67.4, 65.6];

radintens=[64, 90, 399, 662, 981, 1220, 1366, 1376, 1284, 1072, 777, 469, 221];
heat=[138.138, 138.138, 138.138, 368.368, 644.644, 690.69, 782.782, 736.736, 782.782, 690.69, 690.69, 552.552, 368.368];

a = plotyy(t, cintemp, t, radintens );
hold(a(1), 'on')
hold(a(2), 'on');
plot(a(1), t, couttemp);
plot(a(2), t, heat);
hold(a(1), 'off');
hold(a(2), 'off');
title(a(1), 'Solar Energy')
xlabel(a(1), 'Time')
ylabel(a(1), 'Temperature')
ylabel(a(2), 'Energy Rate')
set(a(1).Children(2), 'DisplayName', 'Collector input temperature', 'Color', [0 114 189]/255)
set(a(1).Children(1), 'DisplayName', 'Collector output temperature', 'Color', [237 177 32]/255)
set(a(2).Children(2), 'DisplayName', 'Radiation intensity (W/m^2)', 'Color', [246 216 143]/255)
set(a(2).Children(1), 'DisplayName', 'Heat (W)', 'Color', [126 47 142]/255)

legend('show')