function angle = cross2d( pta, ptb )
% CROSS2D(pta,ptb)
%   returns the angle in degrees between two points
%   in the (xy-plane) by constructing the cross-product.

va = pta(2,:)-pta(1,:);
vb = ptb(2,:)-ptb(1,:);
va = va/norm(va);
vb = vb/norm(vb);

A = [va; vb];

angle = asin(det(A))*180/pi;


end

Published with MATLAB® 7.14