Lec 10 - Visualization with ggplot2

# Lec 10 - Visualization with ggplot2
## <br/> Statistical Programming
### Sta 323 | Spring 2022
### <br/> Dr. Colin Rundel

---

---
class: middle, center

---

## The Grammar of Graphics

- Visualization concept created by Leland Wilkinson (The Grammar of Graphics, 1999)
- attempt to taxonimize the basic elements of statistical graphics

- Adapted for R by Hadley Wickham (2009)
- consistent and compact syntax to describe statistical graphics
- highly modular as it breaks up graphs into semantic components

- ggplot2 is not meant as a guide to which graph to use and how to best convey your data (more on that later), but it does have some strong opinions.

---

## Terminology

A statistical graphic is a...

- mapping of **data**
- which may be **statistically transformed** (summarized, log-transformed, etc.)
- to **aesthetic attributes** (color, size, xy-position, etc.)
- using **geometric objects** (points, lines, bars, etc.)
- and mapped onto a specific **facet** and **coordinate system**

---

## Anatomy of a ggplot call

```r
ggplot(
  data = [dataframe], 
  mapping = aes(
    x = [var x], y = [var y], 
    color = [var color], 
    shape = [var shape],
    ...
  )
) +
  geom_[some geom](
    mapping = aes(
      color = [var geom color],
      ...
    )
  ) +
  ... # other geometries
  scale_[some axis]_[some scale]() +
  facet_[some facet]([formula]) +
  ... # other options
```

---

## Data - Palmer Penguins

Measurements for penguin species, island in Palmer Archipelago, size (flipper length, body mass, bill dimensions), and sex.

.pull-left-narrow[
<img src="imgs/penguins.png" width="100%" style="display: block; margin: auto;" />
]
.pull-right-wide[

```r
library(palmerpenguins)
penguins
```

```
## # A tibble: 344 × 8
##    species island    bill_length_mm bill_depth_mm flipper_length_mm
##    <fct>   <fct>              <dbl>         <dbl>             <int>
##  1 Adelie  Torgersen           39.1          18.7               181
##  2 Adelie  Torgersen           39.5          17.4               186
##  3 Adelie  Torgersen           40.3          18                 195
##  4 Adelie  Torgersen           NA            NA                  NA
##  5 Adelie  Torgersen           36.7          19.3               193
##  6 Adelie  Torgersen           39.3          20.6               190
##  7 Adelie  Torgersen           38.9          17.8               181
##  8 Adelie  Torgersen           39.2          19.6               195
##  9 Adelie  Torgersen           34.1          18.1               193
## 10 Adelie  Torgersen           42            20.2               190
## # … with 334 more rows, and 3 more variables: body_mass_g <int>,
## #   sex <fct>, year <int>
```

]

---

## A basic ggplot

```r
ggplot(
  data = penguins, 
  mapping = aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) +
  geom_point() +
  labs(
    title = "Bill depth and length",
    subtitle = paste(
      "Dimensions for Adelie, Chinstrap,",
      "and Gentoo Penguins"
    ),
    x = "Bill depth (mm)", 
    y = "Bill length (mm)",
    color = "Species"
  )
```

```
## Warning: Removed 2 rows containing missing values (geom_point).
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-6-1.png" width="95%" style="display: block; margin: auto;" />
]

---

# Text <-> Plot

---

```r
*ggplot(data = penguins)
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-7-1.png" width="95%" style="display: block; margin: auto;" />
]

---

```r
ggplot(
  data = penguins,
* mapping = aes(x = bill_depth_mm)
) 
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-8-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> **and map bill length to the y-axis.**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
*   y = bill_length_mm
  )
)
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-9-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> and map bill length to the y-axis. 
> **Represent each observation with a point**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) + 
* geom_point()
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-10-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> and map bill length to the y-axis. 
> Represent each observation with a point
> **and map species to the color of each point.**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) + 
  geom_point(
*   mapping = aes(color = species)
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-11-1.png" width="95%" style="display: block; margin: auto;" />
]

---

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
* labs(title = "Bill depth and length")
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-12-1.png" width="95%" style="display: block; margin: auto;" />
]

---

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
  labs(
    title = "Bill depth and length",
*   subtitle = paste("Dimensions for Adelie,",
*                    "Chinstrap, and Gentoo",
*                    "Penguins")
  ) 
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-13-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> and map bill length to the y-axis. 
> Represent each observation with a point
> and map species to the color of each point.
> Title the plot "Bill depth and length", 
> add the subtitle "Dimensions for Adelie, Chinstrap, and Gentoo Penguins", 
> **label the x and y axes as "Bill depth (mm)" and "Bill length (mm)", respectively**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
  labs(
    title = "Bill depth and length",
    subtitle = paste("Dimensions for Adelie,",
                     "Chinstrap, and Gentoo",
                     "Penguins"),
*   x = "Bill depth (mm)",
*   y = "Bill length (mm)"
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-14-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> and map bill length to the y-axis. 
> Represent each observation with a point
> and map species to the color of each point.
> Title the plot "Bill depth and length", 
> add the subtitle "Dimensions for Adelie, Chinstrap, and Gentoo Penguins", 
> label the x and y axes as "Bill depth (mm)" and "Bill length (mm)", respectively,
> **label the legend "Species"**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
  labs(
    title = "Bill depth and length",
    subtitle = paste("Dimensions for Adelie,",
                     "Chinstrap, and Gentoo",
                     "Penguins"),
    x = "Bill depth (mm)",
    y = "Bill length (mm)",
*   color = "Species"
  ) 
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-15-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> and map bill length to the y-axis. 
> Represent each observation with a point
> and map species to the color of each point.
> Title the plot "Bill depth and length", 
> add the subtitle "Dimensions for Adelie, Chinstrap, and Gentoo Penguins", 
> label the x and y axes as "Bill depth (mm)" and "Bill length (mm)", respectively,
> label the legend "Species", 
> **and add a caption for the data source.**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
  labs(
    title = "Bill depth and length",
    subtitle = paste("Dimensions for Adelie,",
                     "Chinstrap, and Gentoo",
                     "Penguins"),
    x = "Bill depth (mm)",
    y = "Bill length (mm)",
    color = "Species",
*   caption = "Source: palmerpenguins package"
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-16-1.png" width="95%" style="display: block; margin: auto;" />
]

---

.midi[
> Start with the `penguins` data frame,
> map bill depth to the x-axis
> and map bill length to the y-axis. 
> Represent each observation with a point
> and map species to the color of each point.
> Title the plot "Bill depth and length", 
> add the subtitle "Dimensions for Adelie, Chinstrap, and Gentoo Penguins", 
> label the x and y axes as "Bill depth (mm)" and "Bill length (mm)", respectively,
> label the legend "Species", 
> and add a caption for the data source.
> **Finally, use the viridis color palete for all points.**
]

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
  labs(
    title = "Bill depth and length",
    subtitle = paste("Dimensions for Adelie,",
                     "Chinstrap, and Gentoo",
                     "Penguins"),
    x = "Bill depth (mm)",
    y = "Bill length (mm)",
    color = "Species",
    caption = "Source: palmerpenguins package"
  ) +
* scale_color_viridis_d()
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-17-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Argument names

Often we omit the names of first two arguments when building plots with `ggplot()`.

```r
ggplot(
  data = penguins,
  mapping = aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    mapping = aes(color = species)
  ) +
  scale_color_viridis_d()
```
]
.pull-right[

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm,
    y = bill_length_mm
  )
) +
  geom_point(
    aes(color = species)
  ) +
  scale_color_viridis_d()
```
]

---

# Aesthetics

---

## Aesthetics options

Commonly used characteristics of plotting geometries that can be **mapped to a specific variable** in the data, examples include:

- position (`x`, `y`)
- `color`
- `shape`
- `size`
- `alpha` (transparency)

Different geometries have different aesthetics that can be used - see the [ggplot2 geoms](https://ggplot2.tidyverse.org/reference/index.html#Geoms) help files for listings.

* Aesthetics given in `ggplot()` apply to all `geom`s.

* Aesthetics for a specific `geom_*()` can be overridden via the `mapping` argument.

---

## color

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point(
*   aes(color = species)
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-18-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Shape

Mapped to a different variable than `color`

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) +
  geom_point(
    aes(
*     color = species,
*     shape = island
    )
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-19-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Shape

Mapped to same variable as `color`

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) +
  geom_point(
    aes(
*     color = species,
*     shape = species
    )
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-20-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Size

Using a fixed value (note this value is outside of the `aes` call)

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) +
  geom_point(
    aes(
      color = species,
      shape = species
    ),
*   size = 3
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-21-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Size

Mapped to a variable

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) +
  geom_point(
    aes(
      color = species,
      shape = species,
      size = body_mass_g
    ),
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-22-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Alpha

```r
ggplot(
  penguins,
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) +
  geom_point(
    aes(
      color = species,
      shape = species,
      alpha = body_mass_g
    ),
    size = 3
  )
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-23-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Mapping vs settings

- **Mapping:** Determine an aesthetic (the size, alpha, etc.) of a geom based on the values of a variable in the data
  - wrapped by `aes()` and pass as `mapping` argument to `ggplot()` or `geom_*()`.

- **Setting:** Determine an aesthetic (the size, alpha, etc.) of a geom **not** based on the values of a variable in the data, usually a constant value.
  - passed directly into `geom_*()` as an argument.

From the previous slide `color`, `shape`, and `alpha` are all **aesthetics** while `size` is a **setting**.

---

# Faceting

---

## Faceting

- Smaller plots that display different subsets of the data

- Useful for exploring conditional relationships and large data

- Also referred to as "small multiples"

---

## facet_grid

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point() +
* facet_grid( species ~ island )
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-24-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Compare with ...

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point(
    aes(
      color = species,
      shape = island
    ), 
    size = 3
  )
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-25-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## facet_grid (cols)

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point() +
* facet_grid(  ~ species )
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-26-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## facet_grid (rows)

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point() +
* facet_grid( species ~ . )
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-27-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## facet_wrap

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point() +
* facet_wrap(~ species)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-28-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## facet_wrap

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm
  )
) + 
  geom_point() +
* facet_wrap(~ species, ncol = 2)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-29-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Faceting and color

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm, 
    color = species
  )
) +
  geom_point() +
  facet_grid(species ~ sex)
```
]
.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-30-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Hiding redundancy

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm, 
    color = species
  )
) +
  geom_point() +
  facet_grid(species ~ sex) +
* guides(color = "none")
```

```
## Warning: Removed 2 rows containing missing values (geom_point).
```
]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

<img src="Lec10_files/figure-html/unnamed-chunk-31-1.png" width="95%" style="display: block; margin: auto;" />
]

---
class: middle

# A brief plot Tour of ggplot2 plots

---

## Histograms

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
  )
) +
  geom_histogram()
```

```
## `stat_bin()` using `bins = 30`. Pick better value with
## `binwidth`.
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-32-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Histograms - bins

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
  )
) +
  geom_histogram(bins = 50)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-33-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Histograms - binwidth

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
  )
) +
  geom_histogram(binwidth = 250)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-34-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Histograms - color

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
    color = species
  )
) +
  geom_histogram(bins = 20)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-35-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Histograms - fill

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
    fill = species
  )
) +
  geom_histogram(bins = 20)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-36-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Histograms - position

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
    fill = species
  )
) +
  geom_histogram(
    bins = 20,
    position = "identity",
    alpha = 0.5
  )
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-37-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Histograms - facets

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
    fill = species
  )
) +
  geom_histogram(bins = 20) +
  facet_grid(species ~ .) + 
  guides(fill = "none")
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-38-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Density plot

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g
  )
) +
  geom_density()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-39-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Density plot - fill

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g, 
    fill = species
  )
) +
  geom_density(alpha = 0.25)
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-40-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Density plot - adjust

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g,
    fill = species
  )
) +
  geom_density(
    adjust = 0.5, 
    alpha = 0.25
  )
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-41-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Violin plot

```r
ggplot(
  penguins, 
  aes(
    x = species,
    y = body_mass_g,
    fill = species
  )
) +
  geom_violin()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-42-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Ridge plot

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g,
    y = species,
    fill = species
  )
) +
  ggridges::geom_density_ridges(alpha = 0.5)
```

```
## Picking joint bandwidth of 153
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-43-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Ridge plot - more categories + dplyr

```r
penguins %>%
  mutate(
    species_sex = paste0(species, " (", sex, ")")
  ) %>%
  ggplot(
    aes(
      x = body_mass_g,
      y = species_sex,
      fill = species
    )
  ) +
  ggridges::geom_density_ridges(alpha = 0.5)
```

```
## Picking joint bandwidth of 127
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-44-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Box plot

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g,
    y = species
  )
) +
  geom_boxplot()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-45-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Box plot - coord_flip

```r
ggplot(
  penguins, 
  aes(
    x = body_mass_g,
    y = species
  )
) +
  geom_boxplot() + 
  coord_flip()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-46-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Box plot - swap coords

```r
ggplot(
  penguins, 
  aes(
    x = species,
    y = body_mass_g
  )
) +
  geom_boxplot()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-47-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Scatter plot

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm, 
    color = species
  )
) +
  geom_point() 
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-48-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Scatter plot - geom_smooth

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm, 
    color = species
  )
) +
  geom_point() +
  geom_smooth(
    fullrange = TRUE
  )
```

```
## `geom_smooth()` using method = 'loess' and formula 'y ~ x'
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-49-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Scatter plot - geom_smooth w/ lm

```r
ggplot(
  penguins, 
  aes(
    x = bill_depth_mm, 
    y = bill_length_mm, 
    color = species
  )
) +
  geom_point() +
  geom_smooth(
    method = "lm",
    se = FALSE,
    fullrange = TRUE
  )
```

```
## `geom_smooth()` using formula 'y ~ x'
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-50-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Line plot

```r
penguins %>%
  count(species, year) %>%
  ggplot(
    aes(
      x = year, 
      y = n, 
      color = species,
      group = species
    )
  ) +
  geom_line()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-51-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Line plot - with points

```r
penguins %>%
  count(species, year) %>%
  ggplot(
    aes(
      x = year, 
      y = n, 
      color = species,
      group = species
    )
  ) +
  geom_line() + 
  geom_point()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-52-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Bar plot

```r
ggplot(
  penguins, 
  aes(
    x = species
  )
) +
  geom_bar()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-53-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Stacked bar plot

```r
ggplot(
  penguins, 
  aes(
    x = species,
    fill = island
  )
) +
  geom_bar()
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-54-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Stacked relative frequency bar plot

```r
ggplot(
  penguins, 
  aes(
    x = species,
    fill = island
  )
) +
  geom_bar(position = "fill")
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-55-1.png" width="95%" style="display: block; margin: auto;" />
]

---

## Dodged bar plot

```r
ggplot(
  penguins, 
  aes(
    x = species,
    fill = sex
  )
) +
  geom_bar(position = "dodge")
```
]

.pull-right[
<img src="Lec10_files/figure-html/unnamed-chunk-56-1.png" width="95%" style="display: block; margin: auto;" />
]

---
class: middle

# Exercises

---

## Exercise 1

Recreate, as faithfully as possible, the following plot using ggplot2 and the `penguins` data.

---

## Exercise 2

Recreate, as faithfully as possible, the following plot from the `palmerpenguin` package readme in ggplot2.