I have been trying to put my graphic axis in log2 scale but something quite odd appears on the figure. The first data 63 appears at the beggining and the end of the x-scale and for some reason the first point does not appear. Also the points are not exactly centered on the x-ticks... do you have any idea why ?
Thanks in advance for you help !!!
clear all; clc;
%% Vectors
freq=[63 125 250 500 1000 2000 4000 8000 16000]
logfreq=log2(freq);
Lp1=[93.9 93.9 93.8 93.8 93.8 93.6 93.3 91.8 87.8]
Lp2=[93.9 93.9 93.8 93.8 94 94.1 94.4 94.6 95.3]
Lp3=[93.9 93.9 93.9 93.8 94.1 94.4 95.2 97.2 100.9]
%% Plot
figure
plot(log2(freq),Lp1,'+-','linewidth',1.7)
hold on; grid on;
plot(log2(freq),Lp2,'+-','linewidth',1.7)
plot(log2(freq),Lp3,'+-','linewidth',1.7)
set(gca,'fontsize',20)
set (gca, 'XTickLabel', logfreq);
set(gca,'XTickLabel',
{'63','125','250','500','1000','2000','4000','8000','16000'})
xlabel('Frequency [Hz]','fontsize',20)
ylabel('Pressure Level [dB]','fontsize',20)
leg=legend({'Sin correcion','Campo libre','Incidencia aleatoria'},'fontsize',18)
And here is the figure :
You want
set(gca,'XTick',logfreq);
instead of set(gca,'XTickLabel',logfreq)
With your incorrect code, the 63 appears at the start and the end because there are (incorrectly) 10 x tick locations but you are specifying only 9 labels, and hence the first one is repeated. (If you'd only specified 8 then the first 2 would be repeated, etc.)
Related
I have a discrete signal x of length N traced in MATLAB using the command
stem(abs(x)); axis([0 N+6 0 4]);
The resulted figure is shown below:
My question I need only some values corresponding for example to index [7 10 11 12 15 18 48 50 52 60] to be colored with different color , let's say with red.
How can I do that into my figure ?
Using Multiple Plots by hold on and Matrix Indexing
You could possibly and alternatively place a plot on top of plot by using hold on. This does require an adjustment where you need a vector in this case Sample and Indices which specify the sample number/data point index. You can also use matrix indexing to get the amplitude/data points corresponding to the key point, Indicies.
%Vector relating to the sample/data point number%
Sample = linspace(1,70,70);
%Random test data%
X = randi([0,2],1,70);
stem(Sample,X);
hold on
%Key indices to change colour%
Key_Indices = [7 10 11 12 15 18 48 50 52 60];
%Matrix indexing to get values/amplitudes corresponding to key indices%
X_Prime = X(Key_Indices);
stem(Key_Indices,X_Prime,'r');
axis([0 70 0 3]);
hold off
Ran using MATLAB R2019b
This code makes just the circles red and not the stems
plot with selected red circles
%Vector relating to the sample/data point number
Sample = linspace(1,70,70);
%Random test data
X = randi([0,2],1,70);
stem(Sample,X);
%Key indices to change color
Key_Indices = [7 10 11 12 15 18 48 50 52 60];
line(Sample(Key_Indices), X(Key_Indices), 'linestyle', 'none', 'marker', 'o', 'color', 'r')
axis([0 70 0 3])
grid on
I know how to calculate the line parameter defined as x below for one layer, considering the given wavelength range 50 to 550 um. Now I want to repeat this calculation for all 10 layers. all the other parameters remain as a constant while temperature varies from layer 1 to 10.Any suggestion would be greatly appreciated.
wl=[100 200 300 400 500]; %5 wavelengths, 5 spectral lines
br=[0.12 0.56 0.45 0.67 0.89]; % broadening parameter for each wavelength
T=[101 102 103 104 105 106 107 108 109 110];% temperature for 10 layers
wlall=linspace(50,550,40);%all the wavelength in 50um to 550 um range
% x is defined as,
%(br*wl/(br*br + (wlall-wl)^2))*br;
%If I do a calculation for the first line
((br(1)*T(1)*wl(1))./(br(1)*br(1)*(T(1)) + (wlall(:)-wl(1)).^2))*br(1)*T(1)
%Now I'm going to calculate it for all the lines in the first layer
k= repmat(wlall,5,1);
for i=1:5;
kn(i,:)=(br(i)*T(1)* wl(i)./(br(i)*br(i)*T(1) + (k(i,:)-
wl(i)).^2))*br(i)*T(1);
end
%Above code gives me x parameter for all the wavelengths in the
%given range( 50 to 550 um) in the first layer, dimension is (5,40)
% I need only the maximum value of each column
an=(kn(:,:)');
[ll,mm]=sort(an,2,'descend');
vn=(ll(:,1))'
%Now my output has the dimension , (1,40) one is for the first layer, 40 is
%for the maximum x parameter corresponding to each wavelength in first layer
%Now I want to calculate the x parameter in all 10 layers,So T should vary
%from T(1) to T(10) and get the
%maximum in each column, so my output should have the dimension ( 10, 40)
You just need to run an extra 'for' loop for each value of 'T'. Here is an example:
clc; close all; clear all;
wl=[100 200 300 400 500]; %5 wavelengths, 5 spectral lines
br=[0.12 0.56 0.45 0.67 0.89]; % broadening parameter for each wavelength
T=[101 102 103 104 105 106 107 108 109 110];% temperature for 10 layers
wlall=linspace(50,550,40);%all the wavelength in 50um to 550 um range
% x is defined as,
%(br*wl/(br*br + (wlall-wl)^2))*br;
%If I do a calculation for the first line
((br(1)*T(1)*wl(1))./(br(1)*br(1)*(T(1)) + (wlall(:)-wl(1)).^2))*br(1)*T(1)
%Now I'm going to calculate it for all the lines in the first layer
k= repmat(wlall,5,1);
for index = 1:numel(T)
for i=1:5
kn(i,:, index)=(br(i)*T(index)* wl(i)./(br(i)*br(i)*T(index) + (k(i,:)- wl(i)).^2))*br(i)*T(index);
end
an(:, :, index) = transpose(kn(:, :, index));
vn(:, index) = max(an(:, :, index), [], 2);
end
vn = transpose(vn);
I need to calculate a parameter defined as x,( this is defined in my code below) for the given spectral lines in each layer. My atmospheric profile has 10 layers. I know how to calculate x for just one layer. Then I get 5 values for x corresponding to each spectral line ( or wavelength) .
Suppose I want to do this for all 10 layers. Then my output should have 10 rows and 5 columns , size should be (10,5) , 10 represent number of the layer and 5 represent the spectral line. Any suggestion would be greatly appreciated
wl=[100 200 300 400 500]; %5 wavelengths, 5 spectral lines
br=[0.12 0.56 0.45 0.67 0.89]; % broadening parameter for each wavelength
p=[1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 ]; % pressure for 10 layers
T=[101 102 103 104 105 106 107 108 109 110]; % temperature for 10 layers
%suppose I want to caculate a parameter, x for all the layers
% x is defined as,( wavelength*br*T)/p
%when I do the calculation for the first layer,I have to consider all the
%wavelengths , all the broadening parameters and only the first value of
%pressure and only the first value of temperature
for i=1:5;
x(i)= (wl(i)*br(i)*T(1))/p(1);
end
% x is the x parameter for all the wavelengths in the first layer
%Now I want to calculate the x parameter for all the wavelengths in all 10
%layers
%my output should have 10 rows for 10 layers and 5 columns , size= (10,5)
you don't need loops for this case
>> (T./p)'*(wl.*br)
ans =
1.0e+05 *
0.0121 0.1131 0.1364 0.2707 0.4495
0.0136 0.1269 0.1530 0.3037 0.5043
0.0155 0.1442 0.1738 0.3451 0.5729
0.0178 0.1664 0.2006 0.3982 0.6611
0.0210 0.1960 0.2362 0.4690 0.7788
0.0254 0.2374 0.2862 0.5682 0.9434
0.0321 0.2996 0.3611 0.7169 1.1904
0.0432 0.4032 0.4860 0.9648 1.6020
0.0654 0.6104 0.7358 1.4606 2.4253
0.1320 1.2320 1.4850 2.9480 4.8950
I have a series of ordered points (X, Y, Z) and I want to plot a 3D histogram, any suggestions?
I'm trying to do it by this tutorial http://www.mathworks.com/help/stats/hist3.html , but points are random here and presented as a function. My example is easier, since i already know the points.
Furthermore, depending on the number value of Z coordinate, i'd like to colour it differently. E.g. Max value - green, min value - red. Similar as in this case Conditional coloring of histogram graph in MATLAB, only in 3D.
So, if I have a series of points:
X = [32 64 32 12 56 76 65]
Y = [160 80 70 48 90 80 70]
Z = [80 70 90 20 45 60 12]
Can you help me with the code for 3D histogram with conditional coloring?
So far the code looks like this:
X = [32 64 32 12 56 76 65];
Y= [160 80 70 48 90 80 70];
Z= [80 70 90 20 45 60 12];
A = full( sparse(X',Y',Z'));
figure;
h = bar3(A); % get handle to graphics
for k=1:numel(h),
z=get(h(k),'ZData'); % old data - need for its NaN pattern
nn = isnan(z);
nz = kron( A(:,k),ones(6,4) ); % map color to height 6 faces per data point
nz(nn) = NaN; % used saved NaN pattern for transparent faces
set(h(k),'CData', nz); % set the new colors
end
colorbar;
Now I just have to clear the lines and design the chart to make it look useful. But how would it be possible to make a bar3 without the entire mesh on 0 level?
Based on this answer, all you need to do is rearrange your data to match the Z format of that answer. After than you might need to remove edgelines and possibly clear the zero height bars.
% Step 1: rearrange your data
X = [32 64 32 12 56 76 65];
Y= [160 80 70 48 90 80 70];
Z= [80 70 90 20 45 60 12];
A = full( sparse(X',Y',Z'));
% Step 2: Use the code from the link to plot the 3D histogram
figure;
h = bar3(A); % get handle to graphics
set(h,'edgecolor','none'); % Hopefully this will remove the lines (from https://www.mathworks.com/matlabcentral/newsreader/view_thread/281581)
for k=1:numel(h),
z=get(h(k),'ZData'); % old data - need for its NaN pattern
nn = isnan(z);
nz = kron( A(:,k),ones(6,4) ); % map color to height 6 faces per data point
nz(nn) = NaN; % used saved NaN pattern for transparent faces
nz(nz==0) = NaN; % This bit makes all the zero height bars have no colour
set(h(k),'CData', nz); % set the new colors. Note in later versions you can do h(k).CData = nz
end
colorbar;
I have two vectors, x and y that are defined(at random) as follows:
x1=[1000 3000 5000 6000 4000 2000 500 0 -1000 -3000 -5000 -6000 -4000 -2000 -500 1 999 2999 4999];
y1=[5000 4999 4990 3500 2500 2499 2498 2497 2496 2495 2494 1000 -1000 -999 -998 -997 -996 -995 -994];
Following is the plot I obtained by simply typing in plot(x1,y1):
Is there a way to produce a smooth curve from the above data using the interp1 command? I have been told that I should use cubic splines to achieve the desired plot, however, since I am new to Matlab I am unaware of how to implement such a solution. Thanks in advance!
Edit: I have tried to implement it as follows, but I am getting a hideous looking plot!
x1_temp=-6000:100:6000;
pc=pchip(x1,y1,x1_temp);
plot(x1,y1,'o',x1_temp,pc,'-');
How should I modify this code to produce the right plot?
I think you are confused about what you are interpolating. You should interpolate x1 and y1 separately, and afterwards plot them against each other. The following example produces a smooth curve:
x1=[1000 3000 5000 6000 4000 2000 500 0 -1000 -3000 -5000 -6000 -4000 -2000 -500 1 999 2999 4999];
y1=[5000 4999 4990 3500 2500 2499 2498 2497 2496 2495 2494 1000 -1000 -999 -998 -997 -996 -995 -994];
s = [0,cumsum(sqrt(diff(x1).^2+diff(y1).^2))]
N = length(s);
figure();
plot(x1,y1);
hold on
s_fine = interp1(linspace(0,1,N),s,linspace(0,1,5*N));
pcx=interp1(s,x1,s_fine,'spline');
pcy=interp1(s,y1,s_fine,'spline');
plot(pcx,pcy,'r-');