Coordinate systems in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a coordinate system in R plotting?

A coordinate system in R plotting defines how data points are placed on the graph using axes, usually x and y, to show their position visually.

intermediate

What does the coord_cartesian() function do in ggplot2?

coord_cartesian() zooms in or limits the visible area of a plot without removing data points outside the limits.

beginner

How does coord_flip() change a plot?

coord_flip() swaps the x and y axes, turning vertical plots into horizontal ones or vice versa.

intermediate

What is the difference between coord_fixed() and default coordinates?

coord_fixed() fixes the aspect ratio so one unit on the x-axis is the same length as one unit on the y-axis, keeping shapes proportional.

beginner

Why use different coordinate systems in R plots?

Different coordinate systems help show data clearly by changing how axes behave, zooming in, flipping axes, or keeping proportions, making graphs easier to understand.

Which function in ggplot2 flips the x and y axes?

A coord_flip()

B coord_cartesian()

C coord_fixed()

D coord_polar()

coord_flip() swaps the x and y axes in a plot.

What does coord_cartesian(xlim = c(0, 10)) do?

A Flips the axes

B Zooms the plot to show x values between 0 and 10

C Removes data points outside 0 to 10 on x-axis

D Fixes aspect ratio

coord_cartesian() zooms in on the plot area but keeps all data points.

Which coordinate system keeps the aspect ratio fixed?

A coord_flip()

B coord_trans()

C coord_cartesian()

D coord_fixed()

coord_fixed() keeps the aspect ratio so units are equal on both axes.

What happens if you use coord_polar() in ggplot2?

A Plot zooms in

B Axes are flipped

C Plot is shown in polar coordinates (circle)

D Aspect ratio fixed

coord_polar() changes the plot to use polar coordinates, making circular plots.

Why might you use coord_cartesian() instead of setting axis limits directly?

A It zooms without removing data points

B It flips axes

C It changes colors

D It fixes aspect ratio

coord_cartesian() zooms in but keeps all data, unlike setting limits which can remove data.

Explain how different coordinate systems affect the appearance of a plot in R.

Think about how axes and shapes change visually.

Describe a situation where you would use coord_flip() in a plot.

Consider when vertical bars are hard to read.