quiver in cylindrical coordinates

Hi,

I computed cosine directions for vector S as (Lx,Ly,Lz). Where S is a 10*360 array defined on a ring, including two circles of same center. To illustrate the S on the ring the following coordinate transformation was applied:

R=linspace(r1,r2,10);
a=linspace(0,360,360);
for i=1:10
for j=1:360
XX(i,j)=R(i)*cosd(a(j));
YY(i,j)=R(i)*sind(a(j));  
end
end 
pcolor(XX,YY,S)
shading interp

where r1, r2 are the radiuses of the co-center circles. I am wondering if it is possible to visualize the computed cosine directions (Lx,Ly,Lz) on the above pcolor plot in order to indicate the directions of vector S in each radius and angle.

I appreciate your help and time, Farid