# Plot last point of column

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Hello,

I have an output file from fortran model. It have 30 time-steps with 201 depht nodes.

I want to plot the last node of every time-step in funcion of time.

I do know how to take the last value only.

Thanks!

load 'zch4.dat'

tl=201; % Number of depth levels, should be 111. Otherwise check in data

[m,n]=size(zch4); % derermining the size of the data m=concentration, n=depht

% Number of profiles to be plotted

mm=m/tl; % total number of profiles

sm=mm; % tottal profiles

maxDepth = -300;

Time= 0:10:300 %300 years every 10 years

nexttile %CH4 diss

for i=1:30

d=maxDepth ;

hold on

x= 1e6*zch4; % <-- here variable concentration microMole => 1e9 miliMol=>1e6

plot(Time, ( x ((i-1)*tl+1:(i-1)*tl+tl,1)), '', 'LineWidth',1.0) %x=time, Y= i want last value of the every step.

hold off

xlabel ({'Time (years)'}) %label for variable and units

ylabel ({'CH_4 (aq) (mM)'})

% set(gca,'XTick', 0:max(x)/2:max(x) ) %choose the x axis ticks label

set(gca,'XAxisLocation','top')

box on

end

##### 0 Comments

### Answers (3)

KSSV
on 22 Jun 2022

T = readtable('https://in.mathworks.com/matlabcentral/answers/uploaded_files/1040940/zch4.txt') ;

A = table2array(T) ;

[r,c] = size(A);

nlay = r/201;

B = permute(reshape(A',[c,r/nlay,nlay]),[2,1,3]);

iwant = squeeze(B(end,:,:))' ;

##### 0 Comments

William Rose
on 22 Jun 2022

Your script has an error at line

plot(Time, ( x ((i-1)*tl+1:(i-1)*tl+tl,1)), '', 'LineWidth',1.0)

because Time is 1 by 31 and x((i-1)*tl+1:(i-1)*tl+tl,1) is 201 by 1. They must be the same size.

I am not sure exactly what you are trying to plot, and I am not sure how many plots you are trying to create. Your data file has 2 columns and 6030 rows. It appears there are 30 sets of 201 rows. You say that you have 31 time values, but there are only 30 sets of 201 values. You have a for loop that loops 30 times, and generates a new plot every time. Is it your intent to generate a single figure with 30 plots? Or do you want 1 plot with 30 points?

You may find it useful to copy column 1 to an array, and reshape it to have dimensions into a 201 x 30, as shown below:

load('zch4.txt');

tl=201; % Number of depth levels, should be 111. Otherwise check in data

[m,n]=size(zch4);

mm=m/tl;

a=reshape(zch4(:,1),tl,mm); %copy column 1 data into array a, and reshape it.

size(a)

This creates array a, with the data from column 1. The array is 201 rows by 30 columns. Now you can plot the 30 points from the first second , third, and final rows. Is this what you wanted to do?

Time=10:10:300;

plot(Time,a(1,:),'-r.');

hold on;

plot(Time,a(2,:),'-gx');

plot(Time,a(3,:),'-b+');

plot(Time,a(70,:),'-co');

plot(Time,a(140,:),'-m^');

plot(Time,a(end-1,:),'-yv');

plot(Time,a(end,:),'-kd');

legend('Level 1','Level 2','Level 3','Level 70','Level 140','Level 200','Level 201')

xlabel('Time (years)'); ylabel('CH_4 Concentration');

grid on;

Try it. Good luck.

##### 1 Comment

William Rose
on 22 Jun 2022

You can also plot the data at all 201 levels, at different times:

load('zch4.txt');

tl=201;

Level=1:tl;

Time=10:10:300;

[m,n]=size(zch4);

mm=m/tl;

a=reshape(zch4(:,1),tl,mm);

plot(Level,a(:,1),'-r.');

hold on;

plot(Level,a(:,2),'-gx');

plot(Level,a(:,3),'-b+');

plot(Level,a(:,10,:),'-co');

plot(Level,a(:,20,:),'-m^');

plot(Level,a(:,end-1),'-yv');

plot(Level,a(:,end),'-kd');

legend('T=10','T=20','T=30','T=100','T=200','T=290','T=300')

xlabel('Level'); ylabel('CH_4 Concentration');

grid on;

Or you could make a surface plot:

figure;

surf(Time,Level,a,'EdgeColor','none');

xlabel('Time (years)'); ylabel('Level'); zlabel('[CH_4]');

Try it.

Ruben Garcia Paba
on 22 Jun 2022

Edited: Ruben Garcia Paba
on 22 Jun 2022

##### 3 Comments

William Rose
on 23 Jun 2022

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