Improving Graph Readability in R

One common problem with graphs created in R is that many elements end up being too small for their target usage. On slides or in papers, it’s often very hard to read text elements such as legends, axes labels, etc. There is a fairly simple solution to this. If you know in advance the final size of your graph in your paper, you can tell R, and it will make appropriate size decisions for you.

Illustration

Here is the kind of difference you can get simply by changing the saving command: R-code

Option 1: If you save your graphs from a plotting window using the File menu

[You can skip the first step if you know how to manipulate plotting windows.]

1. Plot your graph.
2. Adjust the size of the plotting window: make it small if you want relatively large fonts.
3. Plot your graph again.
4. Now you can save your graph.

Option 2: If you use a command to save your graph

• In many cases, you can specify the final size of your graph within the saving command.
  • If you use ggplot to create your graphs (which you should), ggsave does this perfectly well.
    As you can see, the default values for width and height are taken from the size of the current plotting window. This is the basic problem.
  • quartz.save also has these options. However, the default values are for a 7in by 7in graph, which is rarely suitable for a paper.
• Adjusting the size of the window in advance may also do the trick. This works if your saving function takes the default size values from the current plotting window (e.g., ggsave), but not if the default values are fixed (e.g., the 7in default for quartz.save).

Bonus

Combining Option 1 and Option 2, you can see that the key in Option 1 is that the default size for the saving function in the R menu uses the size of the current plotting window to define the size of the graph you save. What you see is what you save.