25.20 Adjusting Aspect

REVIEW

# Load packages from the local library into the R session.

library(rattle)   # For the weatherAUS dataset.
library(ggplot2)  # To generate a density plot.

# Identify cities of interest.

cities <- c("Canberra", "Darwin", "Melbourne", "Sydney")

# Generate the plot.

weatherAUS %>%
  subset(Location %in% cities & ! is.na(Temp3pm)) %>%
  ggplot(aes(x=Temp3pm, colour=Location, fill=Location)) +
  geom_density(alpha=0.55)

We can fine tune the size of the figure to suit the document and presentation. In this example we have asked R to widen the figure from 7 inches to 14 inches using fig.width=. The code chunk is:

<<myfigure, echo=FALSE, fig.width=14}
... R code ...
@

Underneath, knitr (Xie 2021) is using a PDF device on which the plot is generated, and then saved to file for inclusion in the final document. The PDF device grDevices::pdf(), by default, will generate a 7 inch by 7 inch plot (see ?pdf for details). This is the plot dimensions as we see on the previous page. By setting fig.width= (and fig.height=) we can change the dimensions. In our example here we have doubled the width, resulting in a more pleasing plot.

Notice that as a consequence of the figure being larger the fonts have remained the same size, resulting them appearing smaller now when we include the figure in the same area on the printed page.

References

———. 2021. Knitr: A General-Purpose Package for Dynamic Report Generation in r. https://yihui.org/knitr/.


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