title: Gnuplot x(y) smoothing
body: <p>How do I smooth the data presented in the form x(y)? Gnuplot smoothing function of to invalid handles such cases.</p>
  
  <hr>
  
  <p>As an example:</p>
  
  <p>File(T-L.dat):</p>
  
  <pre><code>0.00    0.0
  0.10    0.1
  0.15    0.2
  0.40    0.3
  0.60    0.4
  0.50    0.5
  0.60    0.6
  0.40    0.7
  0.15    0.8
  0.10    0.9
  0.00    1.0
  </code></pre>
  
  <p><a href="https://yadi.sk/i/hNeMO9b9bkQT4" rel="nofollow">What I want</a>.</p>
  
  <p>Gnuplot session:</p>
  
  <pre><code>knkd@SCP71:~/MEAS/HEAT$ gnuplot
  
          G N U P L O T
          Version 4.6 patchlevel 4    last modified 2013-10-02 
          Build System: Linux x86_64
  
          Copyright (C) 1986-1993, 1998, 2004, 2007-2013
          Thomas Williams, Colin Kelley and many others
  
          gnuplot home:     http://www.gnuplot.info
          faq, bugs, etc:   type "help FAQ"
          immediate help:   type "help"  (plot window: hit 'h')
  
  Terminal type set to 'wxt'
  gnuplot&gt; plot "T-L.dat" with lines
  </code></pre>
  
  <p><a href="https://yadi.sk/i/f8KXGJ8dbkQUJ" rel="nofollow">What I have</a>.</p>
  
  <p>Add smooth:</p>
  
  <pre><code>gnuplot&gt; plot "T-L.dat" with lines smooth csplines
  </code></pre>
  
  <p>Result not good too (only 2 links, sorry).</p>
  
  <p>Other features also not give the result that I wanted to.
  But really I need a spline.</p>