Skip to content

Latest commit

 

History

History
 
 

2022-09-06

Please add alt text to your posts

Please add alt text (alternative text) to all of your posted graphics for #TidyTuesday.

Twitter provides guidelines for how to add alt text to your images.

The DataViz Society/Nightingale by way of Amy Cesal has an article on writing good alt text for plots/graphs.

Here’s a simple formula for writing alt text for data visualization:

Chart type

It’s helpful for people with partial sight to know what chart type it is and gives context for understanding the rest of the visual. Example: Line graph

Type of data

What data is included in the chart? The x and y axis labels may help you figure this out. Example: number of bananas sold per day in the last year

Reason for including the chart

Think about why you’re including this visual. What does it show that’s meaningful. There should be a point to every visual and you should tell people what to look for. Example: the winter months have more banana sales

Link to data or source

Don’t include this in your alt text, but it should be included somewhere in the surrounding text. People should be able to click on a link to view the source data or dig further into the visual. This provides transparency about your source and lets people explore the data. Example: Data from the USDA

Penn State has an article on writing alt text descriptions for charts and tables.

Charts, graphs and maps use visuals to convey complex images to users. But since they are images, these media provide serious accessibility issues to colorblind users and users of screen readers. See the examples on this page for details on how to make charts more accessible.

The {rtweet} package includes the ability to post tweets with alt text programatically.

Need a reminder? There are extensions that force you to remember to add Alt Text to Tweets with media.

LEGO sets

The data this week comes from rebrickable courtesy of Georgios Karamanis.

The LEGO Parts/Sets/Colors and Inventories of every official LEGO set in the Rebrickable database is available for download as csv files here. These files are automatically updated daily. If you need more details, you can use the API which provides real-time data, but has rate limits that prevent bulk downloading of data.

Get the data here

# Get the Data

# Read in with tidytuesdayR package 
# Install from CRAN via: install.packages("tidytuesdayR")
# This loads the readme and all the datasets for the week of interest

# Either ISO-8601 date or year/week works!

tuesdata <- tidytuesdayR::tt_load('2022-09-06')
tuesdata <- tidytuesdayR::tt_load(2022, week = 36)

inventories <- tuesdata$inventories

# Or read in the data manually

inventories <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2022/2022-09-06/inventories.csv.gz')
inventory_sets <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2022/2022-09-06/inventory_sets.csv.gz')
sets <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2022/2022-09-06/sets.csv.gz')

Data Dictionary

inventories.csv.gz

variable class description
id double variable
version double variable
set_num character variable

inventory_sets.csv.gz

variable class description
inventory_id double variable
set_num character variable
quantity double variable

sets.csv.gz

variable class description
set_num character variable
name character variable
year double variable
theme_id double variable
num_parts double variable
img_url character variable

Cleaning Script

library(tidyverse)

all_csvs <- list.files("2022/2022-09-06") |> 
  stringr::str_subset(".csv")
  
all_csvs

inventories <- read_csv("2022/2022-09-06/inventories.csv.gz")
inventory_sets <- read_csv("2022/2022-09-06/inventory_sets.csv.gz")
sets <- read_csv("2022/2022-09-06/sets.csv.gz")

all_df <- left_join(inventories, inventory_sets, by = "set_num") |>
  left_join(sets, by = "set_num") 

ex_plot <- all_df |> 
  ggplot(aes(x = num_parts)) +
  geom_density() +
  scale_x_log10()

ggsave("2022/2022-09-06/pic2.png", ex_plot, dpi = "retina", height = 4, width = 6)