How to do a surf plot for non - uniform data?

Hi all....

I have the matrices x,y and z each of size 30x1. x & y are the X,Y coordinates and z represents the height of the coordinate at that point. I would like do something like a surf plot so that at the respective coordinate i get a surf with the corresponding height)

I have tried something like this.

[x,y] = meshgrid(-3:1/4.9:3); z = p1; //here z is converted from 30x1 to 30x30 because only then peaks can be applied z = peaks(z); surfl(x,y,z); shading interp colormap(jet); axis([-3 3 -3 3 0 2])

Here I have kept the scale fixed as -3 to +3 but the difficulty is I am not able to figure out the 30 coordinates.

My actual x,y, z looks similar to this.

x = [180; 270; 120; 160; 225; 290; 335; 100; 150; 225; 305; 355; 95; 145; 225; 315; 360; 110; 150; 225; 305; 345; 125; 165; 225; 290; 330; 175; 225; 280]; y = [45; 45; 90; 105; 105; 105; 90; 145; 155; 155; 155; 145; 200; 200; 200; 200; 200; 260; 250; 250; 250 ; 260; 320; 310; 310; 310; 320; 360; 360; 360]; z = [1; 5; 6; 19; 18; 16; 16; 4; 16; 19; 23; 20; 6; 18; 21; 21; 13; 12; 12; 20; 21; 20; 11; 8; 23; 18; 17; 19; 20; 1];

And I would like to plot the x&y and then do the surf plot.

Thanks in advance for the help.

Answer 1

[Richard McCulloch]

I'm not sure that I entirely understand the question or the data, but is this what you want?

x = [180; 270; 120; 160; 225; 290; 335; 100;...
    150; 225; 305; 355; 95; 145; 225; 315; ...
    360; 110; 150; 225; 305; 345; 125; 165; ...
    225; 290; 330; 175; 225; 280]; 

y = [45; 45; 90; 105; 105; 105; 90; 145; 155;...
    155; 155; 145; 200; 200; 200; 200; 200; ...
    260; 250; 250; 250 ; 260; 320; 310; 310; ...
    310; 320; 360; 360; 360]; 

temp = [1; 5; 6; 19; 18; 16; 16; 4; 16; 19; 23;... 
    20; 6; 18; 21; 21; 13; 12; 12; 20; 21; ...
    20; 11; 8; 23; 18; 17; 19; 20; 1];

z=zeros(length(x));
for i=1:length(x)
    z(i,i)=temp(i);
end

surf(x,y,z)

It creates the following image:

[Subhiksha]

thank you richard:)

I was already able to produce this image but I would like to have something like a bell shaped curve that we see in the matlab examples for surf

[Richard McCulloch]

That's what I was guessing you wanted. Are you looking for something like this:

z_temp = [1; 5; 6; 19; 18; 16; 16; 4; 16; 19; 23;... 
    20; 6; 18; 21; 21; 13; 12; 12; 20; 21; ...
    20; 11; 8; 23; 18; 17; 19; 20; 1];

x=linspace(-3,3,30);
y=x;

for i=1:length(x)
    for j=1:length(y)
        z(i,j)=z_temp(i);
    end
end

surf(x,y,z)

It might be easier to tell if you describe the function parameters. The image associated with the code above is this

Looking at a scatter plot of the data, I don't see how a clean surface can really be made for the given x,y,z combinations. Maybe I'm just missing something.

Answer 2

[Shivam Anand]

x=[32 20 67 1 98 34 57 65 24 82 47 55 8 51 13 14 18 30 37 39 10 33 21 26 38 81 83 60 95 22 17 5 72 46 99 52 12 25 96 29 70 85 43 69 19 78 97 31 89 53 2 91 48 71 61 15 36 84 94 50 11 80 6 7 49 74 9 88 40 79 27 68 73 64 63 59 86 23 35 58 45 28 100 42 93 87 16 90 41 66 54 92 77 4 62 76 75 56 3 44];
y=[96 75 24 9 83 49 27 77 3 23 17 31 40 13 7 52 51 21 98 47 64 79 78 91 44 16 15 100 84 99 63 68 70 30 54 76 97 73 33 5 88 8 71 66 62 25 60 42 72 45 18 11 28 59 89 65 10 55 69 81 12 26 20 95 87 41 74 50 93 22 43 90 14 34 82 35 56 38 80 32 1 57 6 36 37 61 29 58 2 48 4 46 67 53 92 86 94 19 39 85];
z=[55 31 11 45 83 36 86 49 15 57 42 46 8 94 88 47 54 81 98 41 32 35 56 85 9 89 37 60 23 62 67 100 78 76 73 80 10 20 68 34 77 93 1 63 53 12 22 99 91 40 84 24 33 3 43 19 92 97 6 82 64 25 26 79 95 4 44 58 5 21 70 29 65 87 96 90 51 14 18 2 72 28 71 39 52 7 27 59 50 61 48 30 66 69 17 13 74 16 75 38];
xlin = linspace(min(x), max(x), 100);
ylin = linspace(min(y), max(y), 100);
[X,Y] = meshgrid(xlin, ylin);
% Z = griddata(x,y,z,X,Y,'natural');
% Z = griddata(x,y,z,X,Y,'cubic');
Z = griddata(x,y,z,X,Y,'v4');
mesh(X,Y,Z)
axis tight; hold on
plot3(x,y,z,'.','MarkerSize',15)