# Contour Plot Breaks Off?

Today I experimented with the good old contour plots in R. I plotted my points rather large, because there is quite some uncertainty around their precise placement. In this particular case, I start with an empty plot and a custom range, and add the points separately. Note the `cex=8` to draw extra large points.

```plot(c(80, 740), c(180, 740) , type='n', xlab="", ylab="", bty="n", main="") points(jitter(x), jitter(y), cex=8, pch=19, col="#AA449950")```

Then I added contours, and they were cut off, breaking off where I expected them to go around the dots. Why are there incomplete lines at the top and bottom? It turns out — a.k.a. read the manual — that `kde2d` sets the default limits to the range (I guess this is quite reasonable in other cases): `lims = c(range(x), range(y))`. Now my big dots obviously cover more than the strict range of values, so all I needed to do was set my own lims in kde2d. Here’s the entire code for the plot:
```plot(c(80, 740), c(180, 740) , type='n', xlab="", ylab="", bty="n", main="") points(jitter(x), jitter(y), cex=8, pch=19, col="#AA449950") library(MASS) # z = kde2d(x, y, n=50) # this one didn't work out z = kde2d(x, y, n=50, lims=c(80, 740, 180, 740)) contour(z, drawlabels=FALSE, nlevels=6, col="#AA4499", add=TRUE)```

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