function q=cpol90(a,x,u)
 
% The function CPOL90 plots 2-D image in polar coordinates
% with 0 degrees located at the 12 o'clock position and 
% degrees increasing counter-clockwise.
% To add labels to the contours do: 
%	hold on; eclabel(q,'fontsize',6); .
% Non MATLAB Library routine called is: POLARH
%
% Calling sequence-
% q=cpol90(r,x,u)
%
% Input-
%	a	- the radius
%	x	- the x-y axis column vector
%	u	- the matrix (issued from ro2xy.cpp)
% Output-
%	q	- the handle of the figure
%
% See also-     
% POLARH, RO2XY.cpp.

close
r=a*ones(200,1);
d=linspace(0,2*pi,200)';
polarh(d,r);
%polar(d,r);
hold on
ss=max(max(u));
u=rot90(u)-2*ss;   %rot90 make theta=0 at the top
%u=u-2*ss;   %rot90 make theta=0 at the top
q=pcolor(x,x,flipud(u));
shading interp;
colormap(hsv);
hold off