Color scales and palettes in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a color palette in R?

A color palette in R is a set of colors used together to make plots or graphics look nice and clear. It helps to keep colors consistent and visually appealing.

beginner

How do you create a simple color palette using base R?

You can create a simple color palette using the palette() function, for example: palette(c("red", "green", "blue")) sets the palette to red, green, and blue.

intermediate

What is the purpose of the colorRampPalette() function?

colorRampPalette() creates a function that generates a smooth gradient of colors between given colors. You can use it to make many colors blending from one to another.

beginner

Name two popular R packages for advanced color palettes.

Two popular R packages for color palettes are RColorBrewer and viridis. They provide many ready-to-use palettes for different purposes.

intermediate

What is the difference between sequential and diverging color scales?

Sequential color scales show a progression from light to dark or low to high values, good for ordered data. Diverging scales have two contrasting colors meeting in the middle, useful for showing deviation from a midpoint.

Which function in base R creates a smooth gradient of colors?

A palette()

B colorRampPalette()

C colors()

D colorGradient()

colorRampPalette() creates a function that generates gradients between colors.

Which package provides the brewer.pal() function for palettes?

A RColorBrewer

B scales

C ggplot2

D viridis

brewer.pal() is from the RColorBrewer package.

What type of data is best visualized with a diverging color scale?

A Data with a meaningful midpoint

B Random data

C Categorical data

D Binary data

Diverging scales highlight differences from a midpoint, like zero or average.

Which function sets the current color palette in base R?

A setPalette()

B colorRamp()

C colors()

D palette()

palette() sets or gets the current color palette.

The viridis package is known for palettes that are:

A Random colors

B Only black and white

C Colorblind-friendly and perceptually uniform

D Only pastel colors

viridis palettes are designed to be easy to read by everyone, including colorblind people.

Explain how to create and use a custom color palette in R using base functions.

Think about how you tell R which colors to use and then use them in a plot.

Describe the difference between sequential and diverging color scales and when to use each.

Consider how colors change and what the data represents.