Plotting the trend line without plotting the data

I am trying to plot the trend line for three year data combined, So basically trend line on top the attached scatter plot.

% stack all three years to plot the trend line
msid_3yr = [icedrift_bg_2007;icedrift_bg_2015;icedrift_bg_2017];
wspd_3yr = [wspd_bg_2007;wspd_bg_2015;wspd_bg_2017];

%If i use the following it replaces the existing scatter plot colour dots
mdl = fitlm(wspd_3yr,msid_3yr,'linear')
plot(mdl)

Answer 1

[KSSV]

REad about hold on. After plotting the first, use hold on. Alkso you may go ahead like below:

p = polyfit(wspd_3yr,msid_3yr,1)
xi = wspd_3yr ;
yi = polyval(p,wspd_3yr,msid_3yr) ; 

hold on
plot(xi,yi,'k')

Also when you use:

mdl = fitlm(wspd_3yr,msid_3yr,'linear') ;

mdl has coefficients of the line, you can use polval like shown above to plot.

[Sophia]

@KSSV worked like a charm, thank you so much!

Answer 2

[Chad Greene]

Or more simply,

polyplot(wspd_3yr,msid_3yr)

using the polyplot function found here.