plotting data

hi all, i have a table with 3 variables(B/H)= 1,2,3,4,5,6,7,8 and fi= 0,10,20,30 and h which is depend on (B/H) and fi that contains 32 values. for example for fi=0 and (B/H)=1 >>h=1 fi=0 and (B/H)=2 >>h=1.02 ...... fi=30 and (B/H)=8 >>h=14800

 h:[ 1    1.02  1.11  1.21  1.3   1.4  1.59  1.78      
     1    1.11  1.35  1.62  1.95  2.33 3.34  4.77     
     1.01 1.39  2.12  3.29  5.17  8.29  22    61      
     1.13  2.5  6.36  17.5   50   150  1400  14800 ]

> i would like to plot 3d data.then fit them with 2nd-order polynomial or surface equation for h in terms of fi and (B/H).would anyone please help me to solve that?

tnx in advance,

Answer 1

[Rick Rosson]

Please try:

   sftool

or

   cftool

HTH.

Answer 2

[Brenden]

You can make the plane you will plot h on with meshgrid ex:

[(B/H),fi]= meshgrid(domain of (B/H),domain of fi)

Then you will define the function h using (B/H) and fi or for simplicity you can change the above to X and Y. then you plot the data with:

surf(X,Y,h)

then you can fit this data with something similar to polyfit but you will have to look up the 3d fit

[milad babaei]

tnx for your help,,would u plz tell how could i define h values??please explain more

[Brenden]

if h is a 3d array that is dependent on B/H and fi then you must have some function for this??.. what ever the function is it will most likely require a loop to fill a previously created zero array then you simply surf with your function h and X and Y being the independent variables ...

if you are working with recorded data then the size matters and so you will use meshgrid to make a grid for plotting the recorded data. note that meshgrid will add a zero term in the center of the domain you specify

ex: if you have a image that is 20 pixels wide and high then

[x,y] = meshgrid(-((pixel_dimension-1)/2):((pixel_dimension-1)/2),-((pixel_dimension-1)/2):((pixel_dimension-1)/2));

then mesh grid will make the correct size domain