title: Precise and smooth curve with Tikz
body: <p>I'm trying to draw some curves, but it doesn't work out very well.</p>
  
  <ul>
  <li>what I need</li>
  </ul>
  
  <p><a href="https://i.stack.imgur.com/YZPbv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YZPbv.png" alt="what I need"></a></p>
  
  <ul>
  <li>what I get</li>
  </ul>
  
  <p><a href="https://i.stack.imgur.com/Nji4y.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Nji4y.png" alt="what I get"></a></p>
  
  <pre><code>\documentclass{standalone}
  \usepackage{tikz}
  \usepackage{pgfplots}
  
  \begin{document}
      \begin{tikzpicture}
          \begin{axis}[
              ticks=none,
              xtick distance=1,
              ytick distance=1,
              axis equal image=true,
              grid,
              grid style={gray!50},
              grid=both,
              xlabel={$x$},
              ylabel={$y$},
              axis lines=middle,
              xmin=-4, xmax=9, ymin=-5, ymax=4,
              axis x line=center,
              axis y line=center,
          ]
              \addplot[thick, smooth] plot coordinates
              {
                  (-3, -1)
                  (-.5, -3)
                  (.5, -1.9)
                  (1.5, -2.8)
                  (3.5, 1)
                  (5.5, 3)
                  (7.5, -1.95)
                  (8, -1.5)
              };
          \end{axis}
      \end{tikzpicture}
  \end{document}
  </code></pre>
  
  <p>Is it possible to build such smooth curves without adding a large number of points? In the original drawing, you can see several reference points. Is there any way to configure <code>\addplot</code> or any other command?</p>