I have a problem with 2D plot.

Hi everyone,

I have a problem with adding secondary Xaxis to my plot. I use MATLAB 2017b.

Here is my CODE:

X=[300 400 500 600];
X2=[4 3.5 3.0 2.5];
Y=[0.3 0.4 0.5 0.6];
figure()
plot(X,Y);
ax=gca;
ax.XAxisLocation='top';

Now how to add X2 to the bottom ?

Please help me.

Answer 1

[Sulaymon Eshkabilov]

Here is one possible solution:

X1=[300 400 500 600];
X2=[4 3.5 3.0 2.5];
Y=[0.3 0.4 0.5 0.6];
t = tiledlayout(1,1);
ax1 = axes(t);
plot(ax1,X1,Y,'-r')
ax1.XColor = 'r';
ax1.YColor = 'r';
ax2 = axes(t);
plot(ax2,X2,Y,'ko--')
ax2.XAxisLocation = 'top';
ax2.Color = 'none';

In case, you have two different sets of Y values, then

X1=[300 400 500 600];
X2=[4 3.5 3.0 2.5];
Y1=[0.3 0.4 0.5 0.6];
Y2=10*[0.3 0.4 0.5 0.6]

Y2 = 1×4

3 4 5 6

figure()
TT = tiledlayout(1,1);
ax1 = axes(TT);
plot(ax1,X1,Y1,'-r')
ax1.XColor = 'r';
ax1.YColor = 'r';
ax2 = axes(TT);
plot(ax2,X2,Y2,'ko--')
ax2.XAxisLocation = 'top';
ax2.YAxisLocation = 'right';
ax2.Color = 'none';
ax1.Box = 'off';
ax2.Box = 'off';

[Sudheendran]

Thank you for the quick response. That was very helpful. Just two more question. I would like to have only one curve and two x axis top and bottom. Would it be possible to modify the first plot ?

tiledlayout function is not available in MATLAB 2017b, would you be able to make any alternative code?

[Sudheendran]

Hi Sulaymon,

It would be very helpful for me to plot like this. Please refer to this picture.

[Sulaymon Eshkabilov]

Most welcome. Glad to be of some help :)

With :) thumbs up!

Answer 2

[Sulaymon Eshkabilov]

It should also work with this syntax

X1=[300 400 500 600];
X2=[4 3.5 3.0 2.5];
Y=[0.3 0.4 0.5 0.6];
t = figure(1);
ax1 = axes(t);
plot(ax1,X1,Y,'-r')
ax1.XColor = 'r';
ax1.YColor = 'r';
ax2 = axes(t);
plot(ax2,X2,Y,'ko--')
ax2.XAxisLocation = 'top';
ax2.Color = 'none';

:

[Sudheendran]

Hi Sulaymon,

Wonderful, Thanks a lot. But is there any way to hide or remove the red or black dashed line ? Then my problem is sloved!

Answer 3

[Dyuman Joshi]

%Random data
x1 = 0:0.1:40;
y1 = 4.*cos(x1)./(x1+2);
x2 = 1:0.2:20;
y2 = x2.^2./x2.^3;

%Define an axes and plot on it
ax1 = axes;
plot(ax1, x1, y1, '-r')

%Get the position of the axes
pos = ax1.Position;

%Define another axes on top of the previous one
ax2 = axes('Position', pos, 'XAxisLocation', 'top', 'Color', 'none');
%plot on it
hold(ax2, 'on')
plot(ax2, x2,y2,'-k')

%synchronize the y-axis
linkaxes([ax1 ax2], 'y')

[Sudheendran]

Thanks a lot, But is there anyway to hide the black curve or red curve?

[Dyuman Joshi]

Yes, one approach is to use white color for the curves -

%Random data
x1 = 0:0.1:40;
y1 = 4.*cos(x1)./(x1+2);
x2 = 1:0.2:20;
y2 = x2.^2./x2.^3;

%Define an axes and plot on it
ax1 = axes;
plot(ax1, x1, y1, '-w')

%Get the position of the axes
pos = ax1.Position;

%Define another axes on top of the previous one
ax2 = axes('Position', pos, 'XAxisLocation', 'top', 'Color', 'none');
%plot on it
hold(ax2, 'on')
plot(ax2, x2,y2,'-w')

%synchronize the y-axis
linkaxes([ax1 ax2], 'y')

[Sudheendran]

Thank you joshi.