How can I export x, y and z matrix to .xyz format file?

Hello everyone

Sincerely asking.

I have x,y and z matrix which the value of every (x,y,z) represent the location of a point. I can use "surf" to export a 3D picture. Now I want to know how can I export my x,y and z matrix to a .xyz fomat file. Please help me. Thank you!

with best wishes

[Guillaume]

What is a XYZ format file?

Possibly this but in that case you also need the element symbol corresponding to each point.

If some other XYZ format file, please specify.

[Z G]

I am sorry my expression is not exact. I mean the file suffix is ".xyz". This format can be read by Gwyddion.

[Guillaume]

A file extension in itself is largely useless. Anybody is free to put a .XYZ extension on their file, it doesn't tell you anything about how the data is stored in the file. Without a description of the file format, we can't help you.

So, either get the documentation of the format, or if you have post a sample XYZ file and we can try to guess its format.

[Z G]

Thank you for your attention.

You're right. The reason why I didn't attach a file as sample is it is not supported to attach.

Now the engineer of Gwyddion tell me to export matrix to .nrrd file and import it into Gwyddion. I am trying to realize it. If you have any idea, please tell me.

Best wishes.

[Guillaume]

Again, without details of the actual file format there's not much we can do to help.

[Z G]

For attaching the original file, I add ".txt' suffix to the original file that gwyddion can deal with. I want to export my matrix as original that can be dealed with by Gwyddion.

[Guillaume]

The file you've attached contains a lot more than just x, y, z coordinates of points. It looks like it starts by an extensive text header. So you first need to know which of the header information, if any, is required and you'd need to supply that required information.

The header is then followed by some binary data, possibly the x, y, z coordinates. In order to even stand a chance to understand how the data is encoded as binary we would need the exact values that have been encoded in the file, and even then it would probably required a lot of work to reverse engineer. For this kind of file, the only reliable way to know how to create them is to have the specs of the format from whomever designed it.

I want to make it clear that a file extension on its own is meaningless, it doesn't necessarily represents what is actually in the file. You can slap a .xyz extension on any file and it doesn't mean that your software will be able to read it. For example, the answer you've accepted slaps a .xyz extension onto a file that contains tab delimited data but if your software expects a file in the format you've attached it will absolutely no idea what to do with that tab delimited file. The answer could be trivially modified to put a .xlsx extension onto the file, it wouldn't mean that excel could read it.

Answer 1

[KSSV]

Let X, Y, Z be your m, n matrices.

x = X(:) ; 
y = Y(:) ; 
z - Z(:) ; 
p = [x y z] ;
fid = fopen('test.xyz', 'wt');
fprintf(fid, [repmat('%.f\t', 1, size(P,2)-1) '%f\n'],P.');
fclose(fid)

[Z G]

Thank you for your attention

Your code is useful.

But the matrix I import into Gwyddion can't be dealed with. I think it is the problem of the software. I have contacted to the software of Gwyddion. Are there any follow up question that I will ask again.

Best wishes.

[Guillaume]

I'm a bit confused. You seem to be saying that the answer doesn't work for you, yet you've accepted it, so I'm unsure if your problem has been solved.

Note that if using recent versions of matlab, the above can be replaced by the simpler:

writematrix('test.xyz', [X(:), Y(:), Z(:)], 'Delimeter', '\t');

And in older versions:

dlmwrite('test.xyz', [X(:), Y(:), Z(:)], '\t');

[Z G]

Though I still can't deal with the data in Gwyddion, I successfully expot matix to .xyz file from Matlab and import the file into Gwyddion by your code. So, I think it is enough.

On the way to solving the problem, every little progress deserves to be recognized. Even if that didn't end the problem, it hlep me to adjust direction.

Thank you.

[Guillaume]

This exports the data as a tab delimited text file. It puts a .xyz extension to that file, it doesn't mean that's what expected by your software at all. It could have put a .xlsx extension onto it, it wouldn't mean that's a file that excel can read.