Data visualization

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# Data visualization
## Grammar of Graphics
### Ben Baumer
### SDS 192</br>Sep 11, 2020</br>(<a href="http://beanumber.github.io/sds192/lectures/mdsr_viz_04-ggplot.html" class="uri">http://beanumber.github.io/sds192/lectures/mdsr_viz_04-ggplot.html</a>)

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![](https://github.com/tidyverse/ggplot2/raw/master/man/figures/logo.png)

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## `ggplot2`

- No one uses `ggplot1`

- implementation of the *grammar of graphics*

- [cheatsheet](https://github.com/rstudio/cheatsheets/raw/master/data-visualization-2.1.pdf)

.footnote[https://ggplot2.tidyverse.org/]

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## What is the "Grammar of Graphics"?

Big idea: independently specify plot building blocks and
combine them to create just about any kind of graphical
display you want

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## Building blocks of data graphics

- data (obvi.)
    - `data`

- geometric objects (the literal stuff we draw)
    - `geom_*()`

- aesthetic mappings (how we draw that stuff)
    - `aes()`

- scales (range of values, colors, etc.)
    - `scale_*()`

- faceting (small multiples)
    - `facet_wrap()`, `facet_grid()`

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## Basic template

```r
library(tidyverse)
ggplot(data = mtcars, aes(x = disp, y = mpg)) + 
  geom_point()
```

![](figures/gg-simple-1.png)

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## More complicated

```r
ggplot(data = mtcars, aes(x = disp, y = mpg, color = factor(cyl))) + 
  geom_point() + 
  geom_line() + 
  facet_wrap(~am) + 
  scale_colour_brewer(palette = "Set1")
```

![](figures/gg-complex-1.png)

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# [Coding Demo]