how to put an scale for arrow size in quiver plot for wind vector over map?

I have plotted wind vector over chlorophyll-a map using quiver, I do not want to put z scale or colorbar to the arrows as it would interfere with the chlorophyll colors. But I want to put a small box with size to wind speed reference for the black arrows as all arrow size is not same. Can anyone please help with how it can be done in matlab.

Thanks in advance!

Answer 1

[KSSV]

[X,Y,Z] = peaks(50) ;
[u,v] = gradient(Z) ;

w = sqrt(u.^2+v.^2) ;

figure
hold on
h1 = pcolor(X,Y,w) ;
h2 = quiver(X,Y,u,v,'k') ;
axis tight

legend(h2,'Arrows')