How to connect minimum points into a line?

How could I connect all minimums on x-ray spectrum into a one straight line? I'm attaching an exemplary spectrum file.

Answer 1

[John D'Errico]

n = length(x);
M = [x,ones(n,1)];
C = lsqlin(M,y,M,y);
C =
      -20.501
       1191.8

plot(x,y,'b.',x,C(2) + C(1)*x,'r-')
grid on

If you actually meant something different, like how do you find ALL the local minima, then connect them with straight lines, then you need to use tools like findpeaks, then just call plot.

[you dah]

Unfortunately, it seems not to work for the entire spectrum. Matlab stops working when I enter the code.