Flying out of a smaller city like Dayton, I’m used to having flight layovers on the way to nearly everywhere I travel. While any layover is going to lengthen a trip, one of the most common complaints I hear from traveling companions is when a layover forces them to fly east to go west, or vice versa.
I started thinking about a way to quantify how bad a layover was, and ultimately decided that it would be best to compare the sum of the (great circle) distances for each of the flights flown compared to the (great circle) distance of a direct flight from the origin to the destination:
This would give me a ratio of how much further I flew than I needed to, where a higher ratio would mean a worse layover. A ratio of 2 would mean I flew twice as far as I needed to, a ratio of 3 would mean three times as far, and so on. A ratio of 1 would mean a layover didn’t add any extra distance at all.
In 2018, I visited Australia and New Zealand, each for the first time. Other than that, my travel was largely similar in nature and quantity to 2017 – frequent routine business trips, with a few weekend vacations thrown in.
I stayed in hotels a record 124 nights this year.
Business travel was down slightly, but my three-week Australia and New
Zealand vacation added a lot of personal hotel nights.
My longest flight was 8,580 miles (13,808 km) from Dallas to Sydney.
This 17–hour flight was the longest I’ve ever been on. I also flew my
second-longest flight ever this year: 6,516 miles (10,486 km) from Auckland to Los Angeles.
I play the geocaching game Ingress, and one of its features is the option to do “missions” – specific collections of waypoints to visit. Most of these are relatively short, with under 20 waypoints in a relatively small geographic area.
However, on a road trip that I took earlier this year, I pulled out Ingress on a break and noticed a mission called Ohio County Courthouses, which required visiting the courthouse in each of Ohio’s eighty-eight counties.
With two recent work trips and a five-city European vacation, combined with the changes to summer time in the US and Europe, I’ve gone through quite a few time zone changes in the past six weeks.
I wanted to find a good way to visualize this, and I ultimately decided on the following format:
Time zones can be challenging to represent, so let’s start with talking about UTC.
UTC (which superseded Greenwich Mean Time, although for our purposes they’re interchangeable) is the time zone of the prime meridian, and it does not change for summer time. UTC is used in situations where an unambiguous, continuous reference time is necessary. For example, flights are scheduled in UTC to avoid confusion about time zones and summer time – effectively, UTC is aviation’s “official” time.
The time zones we’re familiar with (for example, Eastern Standard Time or Eastern Daylight Time) are then represented as differences from UTC. Eastern Standard Time is five hours behind UTC – that is, when it’s 11:00 AM in UTC, it’s 6:00 AM in Eastern Standard Time. Thus, EST is UTC minus 5 hours, written as UTC–5. In the summer, Eastern time shifts an hour forward to Eastern Daylight Time, so EDT is only four hours behind UTC, or UTC–4.
So when I’m flying around between time zones (or switching to Daylight Savings Time), I’m really just changing the number of hours I am ahead of or behind UTC. So for any given moment in time (as represented by UTC, I can plot my offset from UTC.
Thus, in the above chart, the horizontal axis represents UTC, and the vertical axis represents the number of hours I’m offset from UTC. Every horizontal gridline represents a one hour shift. The colored bars represent time I spend in a time zone, and the dark gray lines between them represent travel.
So, for example, when I flew from Reykjavík to Chicago, I had to set my watch back by five hours (as I traveled from UTC+0 to UTC–5).
You can also see from the chart that I went through two shifts to summer time: I was in the US when they changed to DST on 13 March, and I was in Europe when they changed to summer time on 27 March. In each case, my watch had to move an hour forward, even though I didn’t travel anywhere.
Incidentally, with all this talk about UTC and Greenwich Mean Time, I’m happy to report that my Europe trip included a visit to the Royal Greenwich Observatory in London, which is the point that defined both the prime meridian and Greenwich Mean Time!