function retval=plotbnd4(x,y,bnd)
%PLOTBND4 plot boundary of FEM mesh
%   PLOTBND4 is be used to draw the boundary of an existing
%   FEM domain.
%
%   PLOTBND4 can also be used to draw the boundary of a transect.
%   The boundary list can be generated by passing DETBNDY 
%   the transect node coordinates and the element list for
%   the transect.  Then, pass PLOTBND4 the same node coordinates
%   and the boundary list returned from DETBNDY.
%  
%  Input :  x   - x-coordinate list
%           y   - y-coordinate list
%           bnd - boundary node pairs as output from DETBNDY
%
% Output :  hboun - handle to boundary object drawn
%
% Call as:  hboun=plotbnd4(x,y,bnd)
%
% Written by : Brian O. Blanton
%

ns=bnd(:,1);
ne=bnd(:,2);
X=[x(ns) x(ne) NaN*ones(size(ns))]';
Y=[y(ns) y(ne) NaN*ones(size(ns))]';
X=X(:);
Y=Y(:);
hboun=line(X,Y,...
           'Color','k',...
           'Linestyle','-',...
           'LineWidth',2,...
           'Tag','boundary');
           
if nargout==1,retval=hboun;,end
%
%        Brian O. Blanton
%        Curr. in Marine Science
%        15-1A Venable Hall
%        CB# 3300
%        Uni. of North Carolina
%        Chapel Hill, NC
%                 27599-3300
%
%        919-962-4466
%        blanton@marine.unc.edu
%