Putting two FAS figures into one.

Hello,

I am running fourier transform function for two datasets. The script below create two figures and I wonder how to modify to put both in a one plot.

Thanks in advance for any help.

Cheers,

Anna

% load recorded nodal data
acc = load ('/Users/annakowal/Documents/2D_site_analysis/flow_Hamilton/Taieri_2Dprofile/TEST11.out');
acc2 = load ('/Users/annakowal/Documents/2D_site_analysis/flow_Hamilton/Taieri_2Dprofile/TEST12.out');

time = acc(:,1);
time2 = acc2(:,1);

% remove time column from data 
acc(:,1) = [];   
acc2(:,1) = [];

% data descriptors
[nStep, nAcc] = size(acc);
nDOF  = 2;
nNode = nAcc/nDOF;
[nStep2, nAcc2] = size(acc2);
nDOF2  = 2;
nNode2 = nAcc2/nDOF2;

% reshape data 
a = reshape(acc, nStep, nDOF, nNode)/9.80665;
a2 = reshape(acc2, nStep2, nDOF2, nNode2)/9.80665;
dt=0.005;  %time step

% FOURIER AMPLITUDE SPECTRUM
[f,U]=FAS(dt,a);
param.FAS = U;
param.freq = f;

[f,U]=FAS(dt,a2);
param.FAS = U;
param.freq = f;

 function[f,U]=FAS(dt,a)
Ny = (1/dt)/2; %Nyquist frequency (highest frequency)
L  = length(a); %number of points in acc
NFFT = 2^nextpow2(L); % Next power of 2 from length of acc
df = 1/(NFFT*dt); %frequency spacing
U = abs(fft(a,NFFT))*dt; %Fourier amplitudes 
U = U(2:Ny/df+1); %single sided FAS
f = linspace(df,Ny,Ny/df)'; %[small, large, number] frequencies

figure;
plot(f,U,'-r','linewidth',1.5)
grid on
box on
xlabel('Frequency (Hz)','fontsize',16)
ylabel('Fourier Spectral Acceleration (g)','fontsize',16)
legend ('Fourier Amplitude Spectrum')
axis([0 10 -inf inf])
 
return

 end

Answer 1

[Star Strider]

Use the hold function to put multiple plot calls in the same axes.

Example —

figure
plot(x1, y1)
hold on
plot(x2, y2)
plot(x3, y3)
hold off
grid

.

Answer 2

[Walter Roberson]

Remove the call

figure;

Add the call

hold on

after the plotting