A map of the Divvy stations in Chicago

Read the data

As before, 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.

Get total number of departures by station

I use the trip data to get the total number of departures by station. From these data, I create a new table column.

divvy$stations <-
  cbind(divvy$stations,
    data.frame(departures = as.vector(table(divvy$trips$from_station_id))))
summary(divvy$stations$departures)
#    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
#       1     557    3058    6188    9029   90040

Create a Divvy stations map

Plotting the Divvy stations by geographic location (latitude and longitude) does a reasonable job tracing the outlines of the City of Chicago and the Lake Michigan shore. By scaling area of each circle by the number of trips, the location of the downtown is apparent.

I higlighted the University of Chicago Divvy station in red.

divvy$stations <-
  transform(divvy$stations,
            at.uchicago = (name == "University Ave & 57th St"))
ggplot(divvy$stations,aes(x    = longitude,
                          y    = latitude,
                          fill = at.uchicago,
                          size = sqrt(departures))) +
  geom_point(shape = 21,color = "white") +
  scale_fill_manual(values = c("darkblue","red")) +
  theme_minimal() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank())

Session information

This is the version of R and the packages that were used to generate these results.

sessionInfo()
# R version 3.3.2 (2016-10-31)
# Platform: x86_64-apple-darwin13.4.0 (64-bit)
# Running under: macOS Sierra 10.12.5
# 
# locale:
# [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
# 
# attached base packages:
# [1] stats     graphics  grDevices utils     datasets  methods   base     
# 
# other attached packages:
# [1] ggplot2_2.2.1     data.table_1.10.4
# 
# loaded via a namespace (and not attached):
#  [1] Rcpp_0.12.11     assertthat_0.2.0 digest_0.6.12    rprojroot_1.2   
#  [5] plyr_1.8.4       grid_3.3.2       gtable_0.2.0     backports_1.0.5 
#  [9] git2r_0.18.0     magrittr_1.5     scales_0.4.1     evaluate_0.10.1 
# [13] stringi_1.1.2    lazyeval_0.2.0   rmarkdown_1.6    labeling_0.3    
# [17] tools_3.3.2      stringr_1.2.0    munsell_0.4.3    yaml_2.1.14     
# [21] colorspace_1.3-2 htmltools_0.3.6  knitr_1.16       tibble_1.2