Routes updated 7 Sep 2015.
Take a road trip to clear your mind. Take in a few sights and bring home a spoon or other collector's item.
According to Google Maps, how far could you go?
Each of the challenges below involves finding points A and B that yield the longest driving route in Google Maps. Each challenge has its own parameters, but certain rules apply to each challenge.
Any solution to the challenge will surely have a shorter route (not available to the routing algorithm) as well as many more longer ones (duh—it's always easy to pessimize a route).
This topic has been previously discussed on xkcd forums.
As Google Maps updates the routing network, some of the old routes are no longer available, or significantly shorter. This maps challenge page may therefore be out of date.
Don't be surprised if links to old routes show a significantly different distance, or point to a route that no longer exists. Such links, or out-dated entries, are annotated as historical.
Thanks to a route by Dean Sych, the 30,000 km limit has been broken again. And how! By over 3,600 km. Thanks Dean!
Previously, because of new routes through central Africa, route distances dropped by about 6,000 km. Whereas before routing avoided Congo and Algeria, they now go right through them. This made a lot of the 30,000+ km routes much shorter.
historical The longest route used to be 33,540 km from Quoin Point, South Africa to a dirt road in Indonesia. It starts with "Head northeast toward R317." and ends with "Turn left". After Malaysia, it's mostly ferries. Unfortunately, it's gone. Also, routing in Africa is now more optimized, shortening all the trips from south Africa.
historical (Paren' no longer available as a destination) | The 30,000 km limit has been broken by a route from Paren' to Pearly Beach. This was furthered by discovering the bizarrely remote Chimchememel', Russia (from Chimchememel' to Danger Point).
historical (Uelen still not accessible) | The next milestone for a route with ferries is 32,000 km. Unless you have the money to build a road to Uelen, this new limit is a significant challenge. Interested individuals should start digging immediately.
historical Many of the interesting past routes are now gone—the world is getting boring. This fun 191 hour drive from Portugal to Malaysia, shown below, is no longer available. Too bad. Stop off in Turkey to go to the bathroom. Pick up a few aluminum centrifuge tubes from Iran, too. That sounds like fun.
If you attempt this route now, you'll go through China, take longer and burn more gas. Prius C drivers with advanced road endurance skills need apply. You know who you are.
The 20,000 km all-land route limit still stands. Africa's complex routing may provide a solution. Or a local conflict that severs a road or two.
If you play with routes in Google Maps you'll quickly notice that some parts of the world do not appear to be connected to the smarts of the routing algorithm. For example, you cannot drive from Bejing to New Delhi (As of 31 Aug 2015 this is no longer true. A 5,559 km route exists). These holes in the driving fabric pose a challenge in finding long routes.
historical (no more kayak routes) | Google's subtle humour can be found everywhere (though apparently not anymore, since kayaking has been removed from maps and replaced by decidedly un-funny flight routes), such as in step 9 of this Seattle to Hawaii route, which states "Kayak across the Pacific Ocean — 4,436 km". If you have endurance training, you might wish to continue kayaking to Tokyo, for another 6,243 km. For the purpose of this challenge, kayaking is not allowed.
These examples amply demonstrate that the internet was created by people with humor and is used largely by people without it.
No routes from North to South America exist because of this boggy marsh.
As new routes become available, long trips become shorter. For example, introduction of a route across Niger and Algeria cut the original land route with no ferry record from 18,260 km to a mere 15,576 km.
As new routes become available, trips may become longer. Apparently, we're no longer on driving terms with Iran (see the relaxing 8 day drive example above). If you want to go from Lisbon to Singapore, you no longer need your Iran for Dummies book.
If you are interested in visualization and information, explore my global visualization of Google searches by language and find out where in the US people are searching in Chinese.
For the morbidly curious, of interest might be all the really stupid questions people ask Google.
Google Maps routes linked to from this page do not appear to work on iPhone's Safari browser (I have not tested iPad or iPod). A "driving direction not found" error appears. Rest assured, these routes do exist, and can be viewed on a browser on a PC or Mac. Weird.
The routes below are the current answers to the challenge. Do you have a better (longer!) route? Let me know.
The longest land leg is a route along the R504 between the east dock of the a/d Kolyma M56 ferry and the gulag town Magadan, known as the sorrow at the world's end. The previous version of this route went 6 km too far and this created a second leg, though along the same road.
v5 route Sakha Rebuplitis - Magadan 1,601 km (+44 km)
v4 route Haines Junction - Dawson Creek 1,557 km (+25 km)
v3 route Haines Junction - Farmington 1,532 km (+32 km) (submitted by David Jackson)
v2 route Haines Junction - South Taylor 1,500 km (+25 km)
v1 route Haines Junction - Charlie Lake 1,475 km
The longest Google Maps route that does not use ferries takes us from Sagres in Portugal to Khasan in Russia. Thanks to Pieter Vandromme for submitting this route.
v6 route Sagres in Portugal to Tanjung Pengelih Pengerang Johor Malaysia 16,280 km. Thanks to Jørgen Adam Holen for pointing out a better destination in Malaysia. (Google Map route no longer available)
v5 route Duyker Eiland, South Africa - Sidi Bettache, Morocco 15,594 km (+18 km) (Duyker Eiland submitted by David Jackson on xkcd) (Google map route, 12,523 km on 26 Nov 2014, significantly shorter with routing through Congo)
v4 route Pearly Beach, South Africa - Sidi Bettache, Morocco 18,260 km (+84 km) (Google map route 12,673 km on 26 Nov 2014)
The longest Google Maps A–B route that uses ferries. The ferry distance cannot be more than 25% of the entire trip.
Thanks to Dean Sych for this one.
v11 route (7 Sep 2013) Quoin Point, South Africa to Talon, Russia 27,224 km (Google map route). This route takes you from Quoin Point on Cape Agulhas to the edge of nowhere in Russia. During your voyage, you experience the endless visual monotony of sprawling Africa (keeping a wide bearth from Angola), only to end up at the sorrow at the world's end—Magadan, Russia's gulag region.
v9 route (18 Jul 2013) Quoin Point, South Africa to Unknown Road, Indonesia 33,540 km (Google map route no longer available, Map geek Earl Higgins found this route after invalidating v7. The 33,000 km barrier is again, and legitimately, broken.)
v8 route (16 Jul 2013) Unknown Road, Indonesia to Groot Paternoster Reserve, South Africa 32,433 km (Google map route no longer available, Map geek Earl Higgins pointed out that the reverse of the v7 route is significantly shorter. This means that the 33,000 km barrier has, in fact, not been broken. Pity.)
v7 route (6 Jun 2013) Groot Paternoster Reserve, South Africa to Unknown Road, Indonesia 33,634 km (Google map route no longer available, submitted by Sue DoNym on xkcd). (33,557 on 16 Jul 2013; reverse of route is significantly shorter—see v8)
v6 route Chimchememel' Russia - Duyker Eiland, South Africa 31,766 km (+626 km) (Google map route no longer exists, submitted by David Jackson on xkcd)
Today is the day and it's hardly an approximation. In fact, `22/7` is 20% more accurate of a representation of `\pi` than `3.14`!
Time to celebrate, graphically. This year I do so with perfect packing of circles that embody the approximation.
By warping the circle by 8% along one axis, we can create a shape whose ratio of circumference to diameter, taken as twice the average radius, is 22/7.
Regression can be used on categorical responses to estimate probabilities and to classify.
The next column in our series on regression deals with how to classify categorical data.
We show how linear regression can be used for classification and demonstrate that it can be unreliable in the presence of outliers. Using a logistic regression, which fits a linear model to the log odds ratio, improves robustness.
Logistic regression is solved numerically and in most cases, the maximum-likelihood estimates are unique and optimal. However, when the classes are perfectly separable, the numerical approach fails because there is an infinite number of solutions.
Altman, N. & Krzywinski, M. (2016) Points of Significance: Logistic regression. Nature Methods 13:541-542.
Altman, N. & Krzywinski, M. (2016) Points of Significance: Regression diagnostics? Nature Methods 13:385-386.
Altman, N. & Krzywinski, M. (2015) Points of Significance: Multiple Linear Regression Nature Methods 12:1103-1104.
Altman, N. & Krzywinski, M. (2015) Points of significance: Simple Linear Regression Nature Methods 12:999-1000.
Genomic instability is one of the defining characteristics of cancer and within a tumor, which is an ever-evolving population of cells, there are many genomes. Mutations accumulate and propagate to create subpopulations and these groups of cells, called clones, may respond differently to treatment.
It is now possible to sequence individual cells within a tumor to create a profile of genomes. This profile changes with time, both in the kinds of mutation that are found and in their proportion in the overall population.
Clone evolution diagrams visualize these data. These diagrams can be qualitative, showing only trends, or quantitative, showing temporal and population changes to scale. In this Molecular Cell forum article I provide guidelines for drawing these diagrams, focusing with how to use color and navigational elements, such as grids, to clarify the relationships between clones.
Krzywinski, M. (2016) Visualizing Clonal Evolution in Cancer. Mol Cell 62:652-656.
Limitations in print resolution and visual acuity impose limits on data density and detail.
Your printer can print at 1,200 or 2,400 dots per inch. At reading distance, your reader can resolve about 200–300 lines per inch. This large gap—how finely we can print and how well we can see—can create problems when we don't take visual acuity into account.
The column provides some guidelines—particularly relevant when showing whole-genome data, where the scale of elements of interest such as genes is below the visual acuity limit—for binning data so that they are represented by elements that can be comfortably discerned.
Krzywinski, M. (2016) Points of view: Binning high-resolution data. Nature Methods 13:463.