A Data Foundation Nanodegree Course at Udacity.
For my final project during this introductory course into Data Analytics and Data Visualisation, I analysed a set of US Aviation data to answer the following questions.
How did airlines vary on the busiest flight path in the US in 2015 in terms of Delays and Day of Week?
I have created a story in Tableau that will find an answer to this question in 3 steps:
Slide 1: Which was the busiest flight path in the US in 2015?
Slide 2: Which airlines operated on this connection and how many flights did they offer?
Slide 3: Adding all delays together, which airline accumulated the longest delays and on which day of the week?
Slide 1: The connection with the most flights operated in the US in 2015 was from San Francisco to Los Angeles.
Slide 2: These 6 airlines had flights on this route and with 201 flights United Air Lines offered the most in 2015.
Slide 3: By far, Delta Air Lines accumulated the longest delays (with an average Total Travel Time of more than 160mins) and operated particularly bad on Sundays, Wednesdays and Saturdays.
For this visualisation I have chosen the stacked bar chart, because I wanted to show how delays are literately getting “stacked up” during air traffic and to compare which airlines are most affected.
Which airline offers the best service throughout the year between Anchorage and Seattle?
- JetBlue Airways offer the smallest number of flights of just 7-9 in both directions and only operate between May and September. The longest Avg. Arrival Delay has been almost 30mins.
- Same as Alaska Airlines, Delta Air Lines offer flights throughout the year with a surprising avg. performance in January (arriving 40mins early, Anchorage -> Seattle), but struggle with long delays in March and November (Seattle -> Anchorage).
In Line and Area Charts the audience can easily compare a year month-by-month and spot irregularities quickly. To visualize an overall total, like the sum of flights being offered each month, the Area Chart comes in particularly handy.
How is the relationship between Departure Delays and Arrival Delays across all American airlines on average and how is it affected by the Time of Year (Month)?
- Looking at 2015 in total, it seems that most airlines have clustered in the center of the chart, within a Departure Delay range of 8-12 mins and an Arrival Delay range of 4-7 mins.
- Looking at each month individually though, the avg. delay times vary quite significantly.
- It appears that June and December are prone to longer delays than other months, while in September all airlines perform much better than the rest of the year.
- Some “smaller” airlines appear to perform very well, like Hawaiian and Alaska Airlines, while other ones, like Spirit and Frontier Airlines, seem to struggle with delays all the time.
- For some reason, US Airways only operated in the first half of 2015, from January till June.
As we all know, size is usually not a very good encoding for data. In this Scatter Chart, I only used spheres of different sizes as a rough indicator of how many flights the different airlines offer and which ones can be considered as “bigger” or “smaller” airlines. For an accurate comparison of the number of flights, I have added a Bar Chart at the bottom. The Scatter Chart though allows us to easily spot clusters, trends and outliers in the dataset, especially over time with the provided monthly filter.