Environmental Data Analysis and Visualization

Finishing Touches

Base plot

library(tidyverse)
library(palmerpenguins)

basePlot<-ggplot(drop_na(penguins),aes(x=body_mass_g,y=bill_depth_mm,color=species)) +
  geom_point() +
  scale_colour_brewer(palette = "Set1") +
  labs(x="body mass (g)",y="bill depth (mm)",title="Penguin Bill Depths")

Base plot

Using complete themes

basePlot + theme_classic()

Using complete themes

basePlot + theme_dark()

Even more complete themes

library(ggthemes)

basePlot + theme_tufte()

Even more complete themes

library(ggthemes)

basePlot + theme_excel()

Customizing appearance with theme

Theme elements are the non-data parts of your plot (e.g., text, These can be accessed using the theme function:

basePlot + theme(element.name = element_function())

Where element.name refers to the element of the graph (e.g., axis.ticks for the tick marks), and the element_function controls what aspect of it is going to be changed (e.g., line width).

Customizing appearance with theme

  • element_text() controls text face, color, size, angle, etc.

  • element_line() controls line color, linewidth, and linetype

  • element_rect() controls rectangular areas fill and border line

  • element_blank() controls whether an element is drawn or not

    • Note: this will remove a drawing rather than make it invisible!

Customizing plot elements

Customizing plot elements

basePlot + theme(
  plot.background = element_rect(fill = "tan")
  )

Customizing plot elements

Try customizing your graph using the following (use ? to get function help).

Element Function Modifies
plot.background element_rect Plot background area
plot.title element_text Plot title

Customizing axis elements

Customizing axis elements

 basePlot + theme(
   axis.line = element_line(colour = "orange", linewidth = 1)
   )

Customizing axis elements

You can modify just one axis by adding .x or .y to your element name.

 basePlot + theme(
   axis.line = element_line(colour = "orange", linewidth = 1),
   axis.text.x = element_text(angle = 45,vjust=1,hjust = 1,color="blue")
   )

Customizing axis elements

You can remove an element by using element_blank()

 basePlot + theme(
   axis.line = element_line(colour = "orange", linewidth = 1),
   axis.text.x = element_text(angle = 45,vjust=1,hjust = 1,color="blue"),
   axis.ticks = element_blank()
   )

Customizing axes

Try customizing your graph using the following (use ? to get function help).

Element Function Modifies
axis.line element_line() Axis line
axis.text element_text() Text at tick marks
axis.title element_text() Axis title
axis.ticks element_line() Tick marks
axis.ticks.length unit() Length of tick marks

Customizing panel elements

Customizing panel elements

Try customizing your graph using the following (use ? to get function help).

Element Function Modifies
panel.background element_rect() Panel background
panel.grid.major element_line() Major gridlines
panel.grid.minor element_line() Minor gridlines

Customizing legend elements

Customizing legend elements

Try customizing your graph using the following (use ? to get function help).

Element Function Modifies
legend.background element_rect() legend background
legend.key element_rect() background of legend keys
legend.text element_text() legend labels
legend.title element_text() legend name

Output to file

Use ggsave to output to a file and control its size

ggsave("baseplot.pdf",basePlot,width=6,height=4,units="in")

Tomorrow

  • The Lab Exercise for tomorrow will be a short quiz on Canvas dealing with different parts of the course. You will not need to be in the Lab to complete this assignment.

  • Lab time tomorrow will be devoted to completing the final project.

  • I will be in the Data Lab from 4PM to 9PM to consult on final project questions.