Have you ever taken a road trip in the US and thought to yourself “I wonder what La Quinta means”. Well, the late comedian Mitch Hedberg thinks it’s Spanish for next to Denny’s.
If you’re not familiar with these two establishments, Denny’s is a casual diner chain that is open 24 hours and La Quinta Inn and Suites is a hotel chain.
These two establishments tend to be clustered together, or at least this observation is a joke made famous by Mitch Hedberg. In this lab we explore the validity of this joke and along the way learn some more data wrangling and tips for visualizing spatial data.
The inspiration for this lab comes from a blog post by John Reiser on his new jersey geographer blog. You can read that analysis here. Reiser’s blog post focuses on scraping data from Denny’s and La Quinta Inn and Suites websites using Python. In this lab we focus on visualization and analysis of these data. However note that the data scraping was also done in R, and we we will discuss web scraping using R later in the course. But for now we focus on the data that has already been scraped and tidied for you.
In this lab we will use the tidyverse and dsbox packages.
Currently your project is called Untitled Project. Update the name of your project to be “Lab 03 - Visualizing spatial data”.
Pick one team member to complete the steps in this section while the others contribute to the discussion but do not actually touch the files on their computer.
Before we introduce the data, let’s warm up with some simple exercises.
Open the R Markdown (Rmd) file in your project, change the author name to your team name, and knit the document.
Now, the remaining team members who have not been concurrently making these changes on their projects should click on the Pull button in their Git pane and observe that the changes are now reflected on their projects as well.
To help with our analysis we will also use a dataset on US states:
Each observation in this dataset represents a state, including DC. Along with the name of the state we have the two-letter abbreviation and we have the geographic area of the state (in square miles).
What are the dimensions of the Denny’s dataset? (Hint: Use inline R code and functions like
ncol to compose your answer.) What does each row in the dataset represent? What are the variables?
What are the dimensions of the La Quinta’s dataset? What does each row in the dataset represent? What are the variables?
We would like to limit our analysis to Denny’s and La Quinta locations in the United States.
Take a look at the websites that the data come from (linked above). Are there any La Quinta’s locations outside of the US? If so, which countries? What about Denny’s?
Now take a look at the data. What would be some ways of determining whether or not either establishment has any locations outside the US using just the data (and not the websites). Don’t worry about whether you know how to implement this, just brainstorm some ideas. Write down at least one as your answer, but you’re welcomed to write down a few options too.
We will determine whether or not the establishment has a location outside the US using the
state variable in the
lq datasets. We know exactly which states are in the US, and we have this information in the
states dataframe we loaded.
stateis not in
states$abbreviation. The code for this is given below. Note that the
%in%operator matches the states listed in the
statevariable to those listed in
!operator means not. Are there any Denny’s locations outside the US?
states that are not in
%>% dn filter(!(state %in% states$abbreviation))
"United States". Remember, you can use the
mutatefunction for adding a variable. Make sure to save the result of this as
dnagain so that the stored data frame contains the new variable going forward.
We don’t need to tell R how many times to repeat the character string “United States” to fill in the data for all observations, R takes care of that automatically.
%>% dn mutate(country = "United States")
Find the La Quinta locations that are outside the US, and figure out which country they are in. This might require some googling. Take notes, you will need to use this information in the next exercise.
Add a country variable to the La Quinta dataset. Use the
case_when function to populate this variable. You’ll need to refer to your notes from Exercise 7 about which country the non-US locations are in. Here is some starter code to get you going:
%>% lq mutate(country = case_when( %in% state.abb ~ "United States", state %in% c("ON", "BC") ~ "Canada", state == "ANT" ~ "Colombia", state # fill in the rest ... ))
Going forward we will work with the data from the United States only. All Denny’s locations are in the United States, so we don’t need to worry about them. However we do need to filter the La Quinta dataset for locations in United States.
<- lq %>% lq filter(country == "United States")
Next, let’s calculate which states have the most Denny’s locations per thousand square miles. This requires joinining information from the frequency tables you created in Exercise 8 with information from the
states data frame.
First, we count how many observations are in each state, which will give us a data frame with two variables:
n. Then, we join this data frame with the
states data frame. However note that the variables in the
states data frame that has the two-letter abbreviations is called
abbreviation. So when we’re joining the two data frames we specify that the
state variable from the Denny’s data should be matched
abbreviation variable from the
%>% dn count(state) %>% inner_join(states, by = c("state" = "abbreviation"))
Before you move on the the next question, run the code above and take a look at the output. In the next exercise you will need to build on this pipe.
Next, we put the two datasets together into a single data frame. However before we do so, we need to add an identifier variable. We’ll call this
establishment and set the value to
"La Quinta" for the
lq data frames, respectively.
<- dn %>% dn mutate(establishment = "Denny's") <- lq %>% lq mutate(establishment = "La Quinta")
Since the two data frames have the same columns, we can easily bind them with the
<- bind_rows(dn, lq)dn_lq
We can plot the locations of the two establishments using a scatter plot, and color the points by the establishment type. Note that the latitude is plotted on the x-axis and the longitude on the y-axis.
ggplot(dn_lq, mapping = aes(x = longitude, y = latitude, color = establishment)) + geom_point()
The following two questions ask you to create visualizations. These should follow best practices you learned in class, such as informative titles, axis labels, etc. See http://ggplot2.tidyverse.org/reference/labs.html for help with the syntax. You can also choose different themes to change the overall look of your plots, see http://ggplot2.tidyverse.org/reference/ggtheme.html for help with these.
Filter the data for observations in North Carolina only, and recreate the plot. You should also adjust the transparency of the points, by setting the
alpha level, so that it’s easier to see the overplotted ones. Visually, does Mitch Hedberg’s joke appear to hold here?
Now filter the data for observations in Texas only, and recreate the plot, with an appropriate
alpha level. Visually, does Mitch Hedberg’s joke appear to hold here?
That’s it for now! In the next lab we will take a more quantitative approach to answering these questions.