Question

I am trying to read in data from a text file and do a 3D plot of it in Matlab. Currently, all I’m getting is a blank plot so my guess is the data is not being stored correctly or at all. Also, I don’t want the 1.000000 at the end of every vector so how can I ignore that? Thanks.

Here is the file:

Blockquote

TechEdge4:<152.266724,173.189377,27.995975>  1.000000
<117.880638,156.116531,27.999983>  1.000000
<129.849899,59.195660,27.999983>  1.000000
<249.321121,60.605404,27.999983>  1.000000
<224.120361,139.072739,28.000668>  1.000000
<171.188950,143.490921,56.933430>  1.000000
<171.188950,143.490921,83.548088>  1.000000
<171.188950,143.490921,27.999985>  1.000000

Here is the code:

file = fopen('C:\Program Files (x86)\Notepad++\testFile.txt'); % open text file

tline = fgetl(file); % read line by line and remove new line characters

% declare empty arrays
CX = [];
CY = [];
CZ = [];

while ischar(tline) % true if tline is a character array

    temp = textscan(tline,'%n%n%n', 'delimiter',',');

    % convert all the cell fields to a matrix
    CX = vertcat(CX, cell2mat(temp));
    CY = vertcat(CY, cell2mat(temp));
    CZ = vertcat(CZ, cell2mat(temp));

    tline = fgetl(file);
end

fclose(file); % close the file

plot3(CX, CY, CZ) % plot the data and label the axises
xlabel('x')
ylabel('y')
zlabel('z') 
grid on
axis square

Answer 1

The way your code is running now, your temp variables are blank in each iteration. Replace the textscan line with

temp = cell2mat(textscan(tline, '<%n,%n,%n>'));

and then the CX, CY, and CZ lines with

CX = vertcat(CX, temp(1));
CY = vertcat(CY, temp(2));
CZ = vertcat(CZ, temp(3));

That should make it work. Of course you will need to handle the first line separately because it has the TechEdge4: thing in it.

Also I suggest adding a check to make sure temp is non-empty before the vertcats.