Multiple plots on one graph (filled.contour)
<p>I would like to combine multiple contour plots on one graph. My code is shown below.</p>

<pre><code>d1&lt;- read.table("/home/amy/Desktop/data.csv",sep=",",header=T)
ax&lt;-d1$c1
ay&lt;-d1$c2
library(MASS)
density1 &lt;- kde2d(ax, ay)
par(mfrow=c(1,2))
filled.contour(density1, xlab= "x axis",
    ylab= "y axis ", main ="first plot", xlim=c(0,100), ylim=c(0,100), 
    color.palette=colorRampPalette(c('white','blue','yellow','darkgreen','darkred')))


    bx&lt;-d1$c3
    by&lt;-d1$c4
    library(MASS)
    density2 &lt;- kde2d(bx, by)
    filled.contour(density2, xlab= "x axis",
        ylab= "y axis ", main ="second plot", xlim=c(0,100), ylim=c(0,100), 
        color.palette=colorRampPalette(c('white','blue','yellow','darkgreen','darkred')))
</code></pre>

<p>An example for my data is shown below.</p>

<p>data.csv</p>

<pre><code>c1     c2    c3    c4

23.7  36.8   45.6  32.5
45.5  23.8   67.5  34.8 
21.6  56.9   12.5  56.7
89.5  45.4   23.3  45.7
</code></pre>