html'>range</a></span>(<span class='no'>z</span>, <span class='kw'>na.rm</span> <span class='kw'>=</span> <span class='fl'>TRUE</span>), <span class='no'>nlevels</span>),
  <span class='kw'>color</span> <span class='kw'>=</span> <span class='st'>"black"</span>,
  <span class='kw'>alpha</span> <span class='kw'>=</span> <span class='fl'>1</span>,
  <span class='kw'>width</span> <span class='kw'>=</span> <span class='fl'>1</span>,
  <span class='kw'>type</span> <span class='kw'>=</span> <span class='fl'>1</spa