function plot_BasisFunction(Th,d,label,i,varargin)
  assert(Th.dim<=2)
  p = inputParser;
  p.PartialMatching=false;
  p.addParamValue('title',true);
  p.parse(varargin{:});
  
  idx=Th.find(d,label);
  qi=Th.sTh{idx}.q(:,i);
  U=Th.sTh{idx}.eval(0);U(i)=1; % coeffs de la ieme fonction de base 

  Th.plotmesh('color','lightgray')
  axis off;hold on
  Th.sTh{idx}.plot(U,'facecolor','None','edgecolor','k')
  plot3([qi(1) qi(1)],[qi(2) qi(2)],[0 1],'k-.')
  view(3)
  if p.Results.title
  funLabName=Th.funLabName(d);
    if fc_tools.comp.isOctave()
      title(['P_1-Lagrange basis function ',funLabName(label),'^h.\phi_{',num2str(i),'}'],'interpreter','tex','fontsize',14)
    else
      title(['$P_1$-Lagrange basis function $',funLabName(label),'^h.\varphi_{',num2str(i),'}$'],'interpreter','latex','fontsize',14)
    end
  end
end

