how to obtain data from plots

Question

Agastya 2015-3-28

评论： Star Strider 2015-3-28

I want to get data from the plot(a,b), if i only know three points in 'a' and three points in 'b'

for an example a=[52 104 157] and b=[0.1 0.4 0.4 ] and i want to know the values of remaining points (e.g value of 'b' for 'a'= 60 etc.)

I want to get all the data points in between in a new file.

please help me with any ideas

Regards Agassi

Answer 1

Star Strider 2015-3-28

Use the interp1 function to do the interpolation:

a=[52 104 157];
b=[0.1 0.4 0.4 ];
b60 = interp1(a, b, 60)

produces:

b60 =
           0.146153846153846

Agastya 2015-3-28

Thank u for early reply, can u please let me know how to get all the possible values of a and b other than those three values

Star Strider 2015-3-28

My pleasure!

Use a vector of values in interp1 rather than a single value.

Since ‘all possible points’ is infinite, I will illustrate a finite version instead:

aq = linspace(min(a), max(a), 10)'; % Query Vector For ‘a’
bq = interp1(a, b, aq)              % Interpolated Values At ‘aq’

produces:

bq =
0000e-003
3077e-003
6154e-003
9231e-003
2308e-003
0000e-003
0000e-003
0000e-003
0000e-003
0000e-003