Last updated: 2019-07-31

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Knit directory: wflow-divvy/analysis/

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Ignored files:
    Ignored:    .DS_Store
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    Ignored:    data/Divvy_Stations_2016_Q1Q2.csv
    Ignored:    data/Divvy_Stations_2016_Q3.csv
    Ignored:    data/Divvy_Stations_2016_Q4.csv
    Ignored:    data/Divvy_Trips_2016_04.csv
    Ignored:    data/Divvy_Trips_2016_05.csv
    Ignored:    data/Divvy_Trips_2016_06.csv
    Ignored:    data/Divvy_Trips_2016_Q1.csv
    Ignored:    data/Divvy_Trips_2016_Q3.csv
    Ignored:    data/Divvy_Trips_2016_Q4.csv
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File Version Author Date Message
html 5357a3b Peter Carbonetto 2019-04-10 Build site.
Rmd 61c85b2 Peter Carbonetto 2019-04-10 wflow_publish(c(“seasonal-trends.Rmd”, “station-map.Rmd”,
html 54fcf4e Peter Carbonetto 2018-04-14 Re-built station-map, time-of-day-trends and seasonal-trends webpages
Rmd de31b24 Peter Carbonetto 2018-04-14 wflow_publish(c(“station-map.Rmd”, “seasonal-trends.Rmd”,
Rmd f163fe4 Peter Carbonetto 2018-04-14 Updates for new workflowr version, v0.11.0.9000.
html f163fe4 Peter Carbonetto 2018-04-14 Updates for new workflowr version, v0.11.0.9000.
html 51163d7 Peter Carbonetto 2018-03-12 Ran wflow_publish(“*.Rmd“) with version v0.11.0 of workflowr.
html ab9176e Peter Carbonetto 2018-03-09 Added code_hiding to the analysis R Markdown files.
html b32e833 Peter Carbonetto 2018-01-18 Re-built all webpages using workflowr v0.1.0.
html 0401587 Peter Carbonetto 2017-11-16 Updated license.html, setup.html, station-map.html and
Rmd 9463eb6 Peter Carbonetto 2017-11-16 wflow_publish(c(“setup.Rmd”, “license.Rmd”, “time-of-day-trends.Rmd”,
Rmd 6b9ddf1 Peter Carbonetto 2017-08-02 Added header with between-section spacing adjustment, and removed <br> tags from R Markdown files.
Rmd c6e8686 Peter Carbonetto 2017-07-31 wflow_publish(Sys.glob(“*.Rmd“))
Rmd 0976f2d Peter Carbonetto 2017-07-24 Minor edit.
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html cbf531a Peter Carbonetto 2017-07-24 Testing local MathJax files.
html abf5116 Peter Carbonetto 2017-07-24 Build site.
Rmd 795b214 Peter Carbonetto 2017-07-24 Added math formulae to time-of-day trends .Rmd file.
html 727b8d9 Peter Carbonetto 2017-07-13 Re-built all the analysis files; wflow_publish(Sys.glob(“*.Rmd“)).
Rmd 6d02ffc Peter Carbonetto 2017-07-13 Made a dozen or so small adjustments to the .Rmd files.
html 597355d Peter Carbonetto 2017-07-07 Ran wflow_publish(c(index.Rmd,first-glance.Rmd,station-map.Rmd,time-of-day-trends.Rmd)).
Rmd f7da4f6 Peter Carbonetto 2017-07-07 Fixed a broken link, and made a bunch of small revisions to the notebooks.
html 2431e84 Peter Carbonetto 2017-07-06 wflow_publish(time-of-day-trends.Rmd)
Rmd c8f7e10 Peter Carbonetto 2017-07-06 Implemented first draft of seasonal trends notebook.
html eb228f2 Peter Carbonetto 2017-07-06 A bunch of small revisions to time-of-day trends notebook.
Rmd 426d238 Peter Carbonetto 2017-07-06 wflow_publish(“time-of-day-trends.Rmd”)
html 9a36e9e Peter Carbonetto 2017-07-06 Build site.
Rmd e67cefb Peter Carbonetto 2017-07-06 Added text to time-of-day-trends.Rmd and fixed up figures a bit.
html 52f577a Peter Carbonetto 2017-07-06 Build site.
Rmd f86e267 Peter Carbonetto 2017-07-06 wflow_publish(“time-of-day-trends.Rmd”)
Rmd 9088b6a Peter Carbonetto 2017-07-06 Build site.

Here we use the Divvy trip data to examine biking trends over the course of a typical day in Chicago.

I begin by loading a few packages, as well as some additional functions I wrote for this project.

library(data.table)
library(ggplot2)
source("../code/functions.R")

Read the data

Following my earlier steps, I use function read.divvy.data to read the trip and station data from the CSV files.

divvy <- read.divvy.data()
# Reading station data from ../data/Divvy_Stations_2016_Q4.csv.
# Reading trip data from ../data/Divvy_Trips_2016_Q1.csv.
# Reading trip data from ../data/Divvy_Trips_2016_04.csv.
# Reading trip data from ../data/Divvy_Trips_2016_05.csv.
# Reading trip data from ../data/Divvy_Trips_2016_06.csv.
# Reading trip data from ../data/Divvy_Trips_2016_Q3.csv.
# Reading trip data from ../data/Divvy_Trips_2016_Q4.csv.
# Preparing Divvy data for analysis in R.
# Converting dates and times.

To make it easier to compile statistics by time of day, I convert the “start hour” column to a factor.

divvy$trips <- transform(divvy$trips,start.hour = factor(start.hour,0:23))

Count departures by time-of-day

Now that start.hour is a factor, it is easy to create a bar chart showing the total number of departures at each hour. Unsurprisingly, we see little biking activity at night. Further, the two peaks (“modes”) in the bar chart nicely recapitulate the morning and afternoon rush hours.

ggplot(divvy$trips,aes(start.hour)) +
  geom_bar(fill = "dodgerblue",width = 0.6) +
  theme_minimal() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank())

Version Author Date
f163fe4 Peter Carbonetto 2018-04-14
b32e833 Peter Carbonetto 2018-01-18
eb228f2 Peter Carbonetto 2017-07-06
52f577a Peter Carbonetto 2017-07-06

However, this bar chart is a bit muddled because it is counting trips during the week and on the weekends. Consider that the bin count \(x[h]\) for hour \(h\) in the histogram above is a sum of the counts for each day of the week:

\[ \begin{align} x[h] & = \sum_{i\;\in\;\mathsf{DaysOfTheWeek}} x_i[h] \\ & = x_{\mathsf{Mon}}[h] + x_{\mathsf{Tue}}[h] + x_{\mathsf{Wed}}[h] + x_{\mathsf{Thu}}[h] + x_{\mathsf{Fri}}[h] + x_{\mathsf{Sat}}[h] + x_{\mathsf{Sun}}[h] \end{align} \]

Note: The math above is embedded in the webpage using MathJax. See here for an excellent reference on MathJax.

Once we plot the counts separately for each the day of the week, the rush-hour trends become more obvious. (Also notice that the rush-hour weeks disappear on Saturday and Sunday.)

ggplot(divvy$trips,aes(start.hour)) +
  geom_bar(fill = "dodgerblue",width = 0.75) +
  facet_wrap(~start.day,ncol = 2) +
  scale_x_discrete(breaks = seq(0,24,2)) +
  theme_minimal() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank())

Version Author Date
b32e833 Peter Carbonetto 2018-01-18
eb228f2 Peter Carbonetto 2017-07-06
9a36e9e Peter Carbonetto 2017-07-06
52f577a Peter Carbonetto 2017-07-06