how can i make a surf from 36 points?

I've 36 points with a height.

X  Y   Z
2  2  0.5
2  4  1
2  6  1.5
2  8  2
2  10  2.5
2  12  3
4  2  0.5
4  4  1
4  6  1.5
4  8  2
4  10  2.5
4  12  3
6  2  0.5
6  4  1
6  6  1.5
6  8  2
6  10  2.5
6  12  3
8  2  0.5
8  4  1
8  6  1.5
8  8  2
8  10  2.5
8  12  3
10  2  0.5
10  4  1
10  6  1.5
10  8  2
10  10  2.5
10  12  3
12  2  0.5
12  4  1
12  6  1.5
12  8  2
12  10  2.5
12  12  3

Now i want to make a surf(3D) but, i get a error. Z must be a matrix, not a scalar or vector.

what function should I use?

Thank you

Answer 1

[Adam]

You need to use meshgrid:

doc meshgrid

to create outputs of the right dimensionality

[Dominique Andriessen]

yes i have done that but, than i get the error: Z must be a matrix, not a scalar or vector.

Answer 2

[Joseph Cheng]

since its nicely ordered and evenly spaced then you can reshape Z vector to

 z = reshape(Z,6,6);

along with

 [x,y]=meshgrid(2:2:12,2:2:12)

then surf(x,y,z).

as i did it quickly i'd double check that the reshaping of the Z column matches up with the meshgrid of x and y. other wise if i got it mixed up then its reshape()' which will be the transpose.

[Dominique Andriessen]

Joseph Cheng is it also possible with these numbers?

Thank you

       X        Y         Z 
  148431.000 459486.000 2.540
  148431.000 459506.000 2.610
  148431.000 459526.000 2.660
  148431.000 459546.000 2.700
  148431.000 459566.000 1.650
  148431.000 459586.000 2.300
  148451.000 459486.000 2.600
  148451.000 459506.000 2.550
  148451.000 459526.000 2.590
  148451.000 459546.000 2.630
  148451.000 459566.000 1.440
  148451.000 459586.000 1.500
  148471.000 459486.000 2.400
  148471.000 459506.000 2.710
  148471.000 459526.000 2.480
  148471.000 459546.000 2.320
  148471.000 459566.000 2.500
  148471.000 459586.000 2.500
  148491.000 459486.000 2.690
  148491.000 459506.000 2.170
  148491.000 459526.000 2.630
  148491.000 459546.000 1.600
  148491.000 459566.000 2.800
  148491.000 459586.000 2.690
  148511.000 459486.000 2.310
  148511.000 459506.000 2.390
  148511.000 459526.000 1.570
  148511.000 459546.000 1.730
  148511.000 459566.000 2.900
  148511.000 459586.000 2.880
  148531.000 459486.000 2.700
  148531.000 459506.000 2.000
  148531.000 459526.000 1.620
  148531.000 459546.000 1.690
  148531.000 459566.000 2.450
  148531.000 459586.000 2.700

[Joseph Cheng]

yes... it still has a grid pattern to it. if it doesn't you'd probably want to use interp2 to fill in between. if you do not want to hard code in the grid then you can also do this

x = reshape(example(:,1),6,6)
y = reshape(example(:,2),6,6)
z = reshape(example(:,3),6,6)
figure,surf(x,y,z)

where example is your table above