How to use griddata() with independent z component

I am trying to plot 2d data in the 3d plane to create a surface that represents the effects of changing z.

Data: Each column of my data represents a X, Y, and a Z value respectively.

@ z=12 I have the data.

d12 =

    0.3000         0   12.0000
    0.2898    0.0776   12.0000
    0.2598    0.1500   12.0000
    0.2121    0.2121   12.0000
    0.1500    0.2598   12.0000
    0.0776    0.2898   12.0000
    0.0000    0.3000   12.0000
   -0.1165    0.4347   12.0000
   -0.2250    0.3897   12.0000
   -0.4243    0.4243   12.0000
   -0.7794    0.4500   12.0000
   -0.8693    0.2329   12.0000
   -0.9000    0.0000   12.0000
   -0.8693   -0.2329   12.0000
   -0.7794   -0.4500   12.0000
   -0.6364   -0.6364   12.0000
   -0.4500   -0.7794   12.0000
   -0.2329   -0.8693   12.0000
   -0.0000   -0.9000   12.0000
    0.2329   -0.8693   12.0000
    0.4500   -0.7794   12.0000
    0.5303   -0.5303   12.0000
    0.3897   -0.2250   12.0000
    0.4347   -0.1165   12.0000
    0.3000   -0.0000   12.0000

@ z=14 I have the data.

d14 =

   -0.2121    0.2121   14.0000
   -0.6495    0.3750   14.0000
   -0.8693    0.2329   14.0000
   -0.9000    0.0000   14.0000
   -0.8693   -0.2329   14.0000
   -0.7794   -0.4500   14.0000
   -0.6364   -0.6364   14.0000
   -0.4500   -0.7794   14.0000
   -0.2329   -0.8693   14.0000
   -0.0000   -0.6000   14.0000
    0.0388   -0.1449   14.0000

In order to use Matlab's built in surface command I need to have the different levels of Z to be of equal dimensions. Therefor I am trying to interpolate the data so that each set of z values have 50 rows and give the surface a round effect. Unfortunately I am not able to successfully do this then plot the result.

So then I tried to use the griddata function and was not successful, here is my attempt.

%--------Start-------------------

[holdX,holdY,holdZ]=[d12(:,1),d12(:,2),d12(:3)] %This is short hand for a function

xstep=(abs(min(holdX)-max(holdX)))/50;

xgrid=[min(holdX):xstep:max(holdX)];

ystep=(abs(min(holdY)-max(holdY)))/50;

ygrid=[min(holdY):ystep:max(holdY)];

zz=zeros(1,length(xgrid)); zz(1,:)=16; zgrid=zz;

x(:,1)=xgrid; y(:,1)=ygrid; z(:,1)=zgrid;

X(:,1)=holdX; Y(:,1)=holdY; Z(:,1)=holdZ;

clearvars holdX holdY holdZ xstep ystep zstep xgrid ygrid zgrid

%----------Round 2--------------------

[holdX,holdY,holdZ]=[d14(:,1),d14(:,2),d14(:3)] %This is short hand for a function

xstep=(abs(min(holdX)-max(holdX)))/50;

xgrid=[min(holdX):xstep:max(holdX)];

ystep=(abs(min(holdY)-max(holdY)))/50;

ygrid=[min(holdY):ystep:max(holdY)];

zz=zeros(1,length(xgrid)); zz(1,:)=14; zgrid=zz;

x(:,2)=xgrid; y(:,2)=ygrid; z(:,2)=zgrid;

X(:,2)=holdX; Y(:,2)=holdY; Z(:,2)=holdZ;

%-----------------Plot----------------

T=griddata(X,Y,Z,x,y,z,'cubic')

%as soon as I run griddata I get an error "Invalid number of input arguments."

I dont think I know how to generate the grid data correctly because I think I need another vector 'v' that corresponds x to X, y to Y and z to Z. Not really sure, please help me out guys if you can. Thank You!

Answer 1

[Aurele Turnes]

It seems like you are trying to get a surface plot in 3 dimensions from 3 n-dimensional vectors (x,y,z). This is not possible in general, because there could be many different surfaces that pass through those points. You might want to use the scatter3 function to visualize your data as follows:

figure
scatter3(d12(:,1),d12(:,2),d12(:,3))
hold on
scatter3(d14(:,1),d14(:,2),d14(:,3))

Refer to the documentation page for scatter3 here .