function han = quiverjw(x,y,u,v,varargin)
% modified quiver that zaps out u,v entries with NaN or 0
u=squeeze(u);
v=squeeze(v);
clip = find(isnan(u)==1|u==0|isnan(v)==1|v==0);
if ~isempty(clip)
  if min(size(x))==1
    % catch the vector x,y usage
    [x,y] = meshgrid(x,y);
  end  
  x(clip) = [];
  y(clip) = [];
  u(clip) = [];
  v(clip) = [];
end
h = quiver(x,y,u,v,varargin{:});
if nargout > 0
  han = h;
end
