11.6 Bar Chart Colour No Legend

20200428

ds %>%
  ggplot(aes(x=wind_dir_3pm, fill=wind_dir_3pm)) +
  geom_bar() +
  scale_y_continuous(labels=comma) +  
  labs(x=vnames["wind_dir_3pm"], y="Count") +
  theme(legend.position="none")

Colour can add interest to a plot, though (unlike this example) it is usually good to use the colour to communicate further information about the data. Nonetheless, it adds to the attractiveness of the visualisation.

A spread of colour is added through the aesthetic fill=wind_dir_3pm. This will fill the bars with colour controlled by the different values of the variable wind_dir_3pm. As this is also the variable being plotted on the x-axis a different colour is chosen for each bar from a good default set of colours.

We add a ggplot2::theme() element here to remove the legend that would be displayed by default, by indicating that the legend.position="none". An alternative to turn the legend off is to provide show.legend=FALSE to the layer (i.e., ggplot2::geom_bar()). This then allows layer specific control of the legends.

---

Your donation will support ongoing availability and give you access to the PDF version of this book. Desktop Survival Guides include Data Science, GNU/Linux, and MLHub. Books available on Amazon include Data Mining with Rattle and Essentials of Data Science. Popular open source software includes rattle, wajig, and mlhub. Hosted by Togaware, a pioneer of free and open source software since 1984. Copyright © 1995-2022 Graham.Williams@togaware.com Creative Commons Attribution-ShareAlike 4.0