Plotting a surface or mesh

hi guys, im new and need matlab for illustrating certain things, easy question therefore

how do i plot these vectors in a three dimensional surface?

x1 = 2,4,6
x2 = 2,4,4,
x3 = 0.1,0.3,0.5

i can do this, but its not working propery, its just giving me points, no surface:

ti = 0:.1:1; 
[XI,YI] = meshgrid(ti,ti);
ZI = griddata(x,y,z,XI,YI);

mesh(XI,YI,ZI), hold;
plot3(x,y,z,'o'), hold off

thank you very much, because this is not working : F = TriScatteredInterp(x,y,z);

[Star Strider]

I can’t run your code. What are x,y,z here and in the plot call?

ZI = griddata(x,y,z,XI,YI);

[xy z]

Hi, thanks for your time. it was just arbitrary use for example x = [2,4,6] y = [2,4,4], z = [0.1,0.3,0.5]

the problem ist, that it only gives me the points via plot3 command, but not the surface, also delaunay doesnt fit it well

*EDIT just saw your latter post, ill check it first

Answer 1

[Star Strider]

This sort of works (it runs and produces an interpolated surface):

x1 = [2,4,6];
x2 = [2,4,4];
x3 = [0.1,0.3,0.5];
x = x1; y = x2; z = x3;                         % Assumption

xi = [2:0.1:6];
yi = [2:0.1:4];
[XI,YI] = meshgrid(xi,yi);                      % Interpolation Grid Must Match Data Range
ZI = griddata(x,y,z,XI,YI);

mesh(XI,YI,ZI), hold;
plot3(x,y,z,'o'), hold off

The griddata function does not allow extrapolation (extrapolation is not mentioned in the documentation), so asking it to do so produces a matrix of NaN values, and NaN values do not plot. This was the reason you were not getting any surface plotted. The scatteredInterpolant class allows extrapolation, so consider using it if you want to extrapolate.

[xy z]

what is meant by Interpolation must match data range? because i have dozens of points thanks

what is the code, if i want to plot all these values? x=[0 0 0 0 0 0.1 0.1 0.1788256 0.2 0.2 0.2714962 0.3 0.3 0.3344274]; y=[3.4 0 3.4 1.88985 0.808687 0 1.062642 3.18 0 1.95117 0.2714962 0 0.352527 0]; z=[1.2808 2.599896 1.2808 1.5 2 1.806426 1.062642 0 1.026753 0 0.2714962 0.26065 0 0];

[Star Strider]

My comment ‘Interpolation must match data range’ means that griddata won’t allow you to extrapolate, so the grid limits have to correspond to the data maxima and minima.

For your other data, the code would be the same, but the grid limits (maxima and minima of the vectors in the meshgrid arguments) would change to accommodate them.

[xy z]

thanks a lot, it worked fine.

[Star Strider]

My pleasure.