Creating Surface Plot from a Matrix with 3 Columns

How do you create a surface plot using a matrix with 3 columns in Matlab? The first column would be the x-values, the second column would be the y-values, and the third column would be the z-values for the surface plot.

[KSSV]

We can help on getting data. Attach your data. We need to know whether your data is structured or unstructured.

[Sarah]

I am generating data from a loop. Here is a simple example from the loop:

0.5000    0.5000   66.9052
0.5000    1.0000   57.3591
1.0000    0.5000   76.7805
1.0000    1.0000   66.9052

[KSSV]

More data is needed.

Answer 1

[KSSV]

A = [0.5000    0.5000   66.9052
0.5000    1.0000   57.3591
1.0000    0.5000   76.7805
1.0000    1.0000   66.9052] ;

x = A(:,1) ; y = A(:,2) ; z = A(:,3) ;

%%structured 
xi = unique(x) ; yi = unique(y) ;
[X,Y] = meshgrid(xi,yi) ;
Z = reshape(z,size(X)) ;
figure
surf(X,Y,Z)
%%unstructured 
dt = delaunayTriangulation(x,y) ;
tri = dt.ConnectivityList ;
figure
trisurf(tri,x,y,z)

[Sarah]

Thank you. What is the "unstructured" section doing/for?

[KSSV]

YOu can plot in either of the ways. Thanks is accepting the answer..:)

[Sarah]

How do you know if you are "structured" vs "unstructured"?

[KSSV]

That's why I asked for complete data....:)

If X, Y have regaular arrangement it is structured or else unstructured.

[Eric]

Wonderful...thank you soooo much for this!!! I was tearing my hair out. :)

[Adithya Valavi]

If you have n no matrix then can we draw multiple suface plot???

[Felicity Currie]

thank you KSSV!

[Timothy Turk]

KSSV - It works with your numbers, but it chokes on mine. I get an error on reshape.

Error using reshape

To RESHAPE the number of elements must not change.

Error in Iridium_Data (line 9)

Z = reshape(z,size(X)) ;

[Rodrigues Bitha]

@Timothy Turk I also encoutered the same issue. To solve this, I removed all the rows of my matrix that were repeated. You can do with the command:

B = unique(A,'rows');

Hope that will be helpful to you or anyone that will come after us.

[Hans Kramer]

Thank you for the answer.

[MOHAMED GHAZI]

KSSV how can I trisurf this matrix I used your email program it does not work.

P1=[1;0;1];

P2= [2; 3;2];

P3= [-3;1;2];

P4= [6;2;3];

MatrixP=[1 2 -3 6 ;0 3 1 2;1 2 2 3];

%%structured

[X,Y] = meshgrid(MatrixP) ;

B = unique(A,'rows');

figure

surf(X,Y,Z)

%%unstructured

dt = delaunayTriangulation(x,y) ;

tri = dt.ConnectivityList ;

figure

trisurf(tri,x,y,z)

Answer 2

[KSSV]

x = speed ; y = Torque ; z = bsfc ;
%%structured 
xi = unique(x) ; yi = unique(y) ;
[X,Y] = meshgrid(xi,yi) ;
Z = reshape(z,size(X)) ;
figure
pcolor(X,Y,Z)
%% griddata
xi = linspace(min(x),max(x));
yi = linspace(min(y),max(y)) ;
[X,Y] = meshgrid(xi,yi) ;
Z = griddata(x,y,z,X,Y)
pcolor(X,Y,Z)