# How to plot 3d from scattered dataset captured from xlsx file?

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Omar on 14 Jul 2020
Commented: Walter Roberson on 15 Jul 2020
Hi.
I have xlsx file ... I'm able to plot it as 2d ... But I want to have the 3d version...
I have attached a sample of the dataset and how the figure looks in 2d and how it should look in 3d diemension
I copied the data to txt file and tried to plot it using the code below, but it didnt work with me
Any suggestions?
Many Thanks
data = dlmread('sample.txt');
x = data(:,1);
y = data(:,2);
z = data(:,3);
figure
surf(reshape(x,1,[]),reshape(y,1,[]),reshape(z,1,[]))
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### Accepted Answer

jonas on 14 Jul 2020
Edited: jonas on 14 Jul 2020
You need gridded data to use surf. You have scattered data.
xyz = readmatrix('sample.xlsx');
[x,y,z] = deal(xyz(:,1),xyz(:,2),xyz(:,3));
[X,Y] = meshgrid(linspace(min(x),max(x),100),...
linspace(min(y),max(y),100));
Z = griddata(x,y,z,X,Y,'linear');
%extrapolate using constant = 0
Z(isnan(Z)) = 0;
surf(X,Y,Z)
Alternatively you could fit a surface to your contours using this FEX function
Also, you probably want to interpolate your data to get more samples, as the resulting fit is very ugly. Could do something like:
t = 1:numel(x);
k = 2;
tv = linspace(min(t),max(t),numel(x)*k);
x = interp1(t,x,tv);
y = interp1(t,y,tv);
z = interp1(t,z,tv);
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jonas on 15 Jul 2020
That is unrelated to OP's question, so you should start a separete one :)
Walter Roberson on 15 Jul 2020
data = cat(1, image_patches,labels);
That code is overwriting all of data each iteration.
It looks to me as if data will not be a vector, but I do not seem to be able to locate any hellopatches() function so I cannot tell what shape it will be. As you are not doing imresize() I also cannot be sure that all of the images are the same size, so I cannot be sure that data will be the same size for each iteration. Under the circumstances you should be considering saving into a cell array.
Note: please do not post the same query multiple times. I found at least 9 copies of your query :(

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