title: Mapping temperature profiles with interpolation
body: <p>I have a script almost ready to plot temperature profiles taken every second day in a lake with interpolating the times not measured. But I cannot get it to run because &quot;Error: <code>mapping</code> must be created by <code>aes()</code>&quot;. Can any of you help? The code looks like this:</p>
  <pre><code>p&lt;-ggplot(Kill,aes(x=Day,y=Depth_minus))+
    geom_raster(aes(fill=Temperature))+
    scale_fill_gradient(low =&quot;blue&quot;,high=&quot;red&quot;)+
    geom_contour(aes(z=Temperature),binwidth=2,colour=&quot;black&quot;,alpha=0.2)+
    geom_point(Kill,aes(x=Day,y=Depth),colour=&quot;black&quot;,size=3,alpha=1,shape=15)+
    theme_classic()+
    labs(y=&quot;Depth (m)\n&quot;,x=&quot;\nDay of August&quot;,colour=&quot;Temperature (°C)&quot;)+
    theme(axis.title.x=element_text(size=20),
          axis.text.x=element_text(size=18,colour=&quot;black&quot;),
          axis.title.y=element_text(size=20),
          axis.text.y=element_text(size=18,colour=&quot;black&quot;),
          axis.ticks=element_line(colour=&quot;black&quot;,size=1),
          axis.line=element_line(colour=&quot;black&quot;,size=1,linetype=&quot;solid&quot;),
          legend.position=&quot;right&quot;,
          legend.text=element_text(colour=&quot;black&quot;,size=17),
          legend.title=element_text(colour=&quot;black&quot;,size=18))
  p
  </code></pre>