This is not normal(ised)

“Sydney stations where commuters fall through gaps, get stuck in lifts” blares the headline. The story tells us that:

Central Station, the city’s busiest, topped the list last year with about 54 people falling through gaps

Wow! Wait a minute…

Central Station, the city’s busiest

Some poking around in the NSW Transport Open Data portal reveals how many people enter every Sydney train station on a “typical” day in 2016, 2017 and 2018. We could manipulate those numbers in various ways to estimate total, unique passengers for FY 2017-18 but I’m going to argue that the value as-is serves as a proxy variable for “station busyness”.

Grabbing the numbers for 2017:

library(tidyverse)

tibble(station = c("Central", "Circular Quay", "Redfern"),
       falls   = c(54, 34, 18),
       entries = c(118960, 27870, 30570)) %>%
  mutate(falls_per_entry = falls/entries) %>%
  select(-entries) %>%
  gather(Variable, Value, -station) %>%
  ggplot(aes(station, Value)) +
    geom_col() +
    facet_wrap(~Variable,
               scales = "free_y")

so1

Looks like Circular Quay has the bigger problem. Now we have a data story. More tourists? Maybe improve the signage.

Deep in the comment thread, amidst the “only themselves to blame” crowd, one person gets it:

Sydney stations where commuters fall through gaps get stuck in lifts

Just use a scatterplot. Also, Sydney sprawls.

Dual-axes at tipping-point

Sydney’s congestion at ‘tipping point’ blares the headline and to illustrate, an interactive chart with bars for city population densities, points for commute times and of course, dual-axes.

Yuck. OK, I guess it does show that Sydney is one of three cities that are low density, but have comparable average commute times to higher-density cities. But if you’re plotting commute time versus population density…doesn’t a different kind of chart come to mind first? y versus x. C’mon.

Let’s explore.
Continue reading

Chart golf: the “demographic tsunami”

“‘Demographic tsunami’ will keep Sydney, Melbourne property prices high” screams the headline.

While the census showed Australia overall is aging, there’s been a noticeable lift in the number of people aged between 25 to 32.
As the accompanying graph shows…

Whoa, that is one ugly chart. First thought: let’s not be too hard on Fairfax Media, they’ve sacked most of their real journalists and they took the chart from someone else. Second thought: if you want to visualise change over time, time as an axis rather than a coloured bar is generally a good idea.

Can we do better?
Continue reading