All posts by Tim De Chant

Are Our Transit Maps Tricking Us?

Jessica Gross, writing for the Atlantic Cities:

London’s city center takes up about two percent of the city. On the Tube map, it looks four times as big.

Over in New York City, Central Park—which is a skinny sliver, much longer than it is wide—was depicted in some 1960s and ‘70s IRT maps as a fat rectangle on its side.

So public transit maps are distorted, quite on purpose. All of them enlarge city centers. Many use a fixed distance between stations out in the boonies, even if, in reality, they’re spaced wildly differently. Curvy lines are made straight. Transfers are coded with dots, lines, and everything in between.

Part of that has to do with design, but I’d guess the other part has to do with the way we assign names to places. When population density increases—as it does in London’s city center—toponymic density also rises.

Last week of the Membership Drive

If you haven’t joined Per Square Mile as a member, now is the time. Just four days remain in the drive. For just $29, you’ll receive a t-shirt in addition to your membership. That’s just under $2.50 a week, which I think is a pretty darn good deal.

Plus, did I mention how good you’ll look in one?

Citizen scientists may beat the pros in identifying at-risk species

Kate Shaw, writing for Ars Technica:

A new study in Science used data from federal reports to determine whether listed species identified by the US Fish and Wildlife Service face greater biological threats than those listed as a result of citizen petitions or lawsuits. After examining the data for more than 900 species, the researchers found that species proposed via either petitions or lawsuits actually face greater biological threats than those identified by the federal agency.

The coming schism in ecology

At this year’s Aspen Environmental Forum, there was a dust-up between ecologist E.O. Wilson and writer Emma Marris. At the heart of their disagreement is how we define nature. Wilson prefers what I’ll call the pre-industrialized version, for lack of a better term (people have been modifying their environments for so long that we can’t say there’s a “pre-human” condition). Marris, author of Rambunctious Garden, is more inclusive, arguing that what Wilson calls degraded ecosystems should be considered for preservation.

Michelle Nijhuis, writing for The Last Word on Nothing, thinks this schism will eventually pass:

The deepest divide may be generational. Wilson, now in his 80s, has explored some of the most biodiverse places in the world. He knows, from long firsthand experience, how much effort it’s taken to protect and begin to restore just a handful of them. He may worry that Emma is leading younger conservationists into a kind of moral relativism, asking them to bestow equal value on vegetable gardens and old-growth forests. Emma, in her 30s, doesn’t want to do that — but neither does she want to simply inherit her predecessors’ endgame, and watch the few remaining places free of human footprints change, shrink, and disappear.

As an ecologist in my 30s, I feel torn between the two viewpoints and not altogether sure that ecology will ever place degraded systems on the same level as wilder ones. Still, I agree with Marris that “pristine” ecosystems don’t exist, and that those with humanity’s fingerprints on them should still be considered for conservation. But instead of debating the metaphysical definition of nature, I think applied conservation should focus on ecosystem function and stability.

The birthplace of English?

Turkish countryside near Hierapolis

I speak English (no surprise). I can also speak German, though more poorly than when I was in college. And I can understand a handful of Spanish, Italian, and Chinese words. But I am completely hopeless when it comes to Russian, Hindi, Tagalog, and hundreds of other languages. It’s a shame, but I know I’m not alone.

Language differences are both a hurdle to common understanding and a window into cultural differences. Which is why linguists, sociologists, and archaeologists are so intent on shedding light on the origin question. Research published today in the journal Science tries to trace the origin of the Indo-European language family, the largest in terms of native speakers and geographic distribution.

There are nearly 450 languages and dialects in the family, including English, German, the Romance languages, Hindi, Russian, and many others. If you haven’t studied them, most of these languages may seem like Greek to you.¹ But many of their words are surprisingly similar, even to the layperson. Take “three”, for example. In German, it’s drei, in Spanish it’s tres, in Greek it’s tria, and in Urdu (spoken in Pakistan and parts of India) it’s pronounced theen.

There are two prevailing theories about the origin of the Indo-European language family. The first proposes that the Kurgan people, a culture common to nomadic herders living on the steppe between and north of the Black and Caspian seas, first started spreading its language some 5,000 years ago. Recent archaeological and linguistic data provide evidence for this hypothesis. The other theory says farmers in Anatolia, or present-day Turkey, spread their tongue along with their farming techniques about 8,000 to 9,000 years ago.

It’s the nomad hypothesis versus the farmer hypothesis. Under the nomadic theory, it’s easy to imagine a more violent expansion of the culture and language, though the Kurgan diffusion may have been peaceful, too. The Anatolian expansion, though, was almost certainly more peaceful, with the language following the adoption of technologically advanced farming techniques.

Both sides have their staunch supporters in academia, but today’s Science paper gives new ammunition to Anatolian advocates. Quentin Atkinson, a senior lecturer at the University of Auckland in New Zealand, and his co-authors started by borrowing from the toolkits of epidemiologists and conservation biologists, using computer models that were first developed to trace the origin of diseases and the geographic ancestry of different species. They fed the models geographic and linguistic data from 103 ancient and modern-day Indo-European languages. Their results supported the Anatolian hypothesis regardless of which model variables they tuned.

Indo-European language origin map

Cladogram and map of the diversification of various Indo-European languages. From Bouckaert et al. 2012 (cited and linked below).

The spread of farming was probably a big driving force behind the geographic expansion of the Indo-European family, Atkinson and his colleagues said, but it wasn’t the only one. They point out that languages continued to spread and diversify well after agriculture was established in many areas, suggesting other factors. While their findings probably won’t settle the debate between the Kurgan and Anatolian camps any time soon, they do provide an intriguing look into the common ancestry shared by so many of our native tongues.


  1. Yes, Greek is an Indo-European language. Sorry for the bad pun.

Source:

Remco Bouckaert, Philippe Lemey, Michael Dunn, Simon J. Greenhill, Alexander V. Alekseyenko, Alexei J. Drummond, Russell D. Gray, Marc A. Suchard, and Quentin D. Atkinson. 2012. “Mapping the Origins and Expansion of the Indo-European Language Family”. Science 337:957-960. DOI: 10.1126/science.1219669

Photo by Ian W. Scott.

Related posts:

The curious relationship between place names and population density

Which reads faster, Chinese or English?

Southern regions nurtured languages

New York City hoping to attract mussels to Pier 35

David W. Dunlap, writing for the New York Times:

Even if the bed at Pier 35 fails to attract mussels, officials envision it as an unusual abstract sculpture that can be used to study the extent and effect of tides. A little bridge will cross over the mouth of the habitat, which occupies a small cove. At high tide, the structure will be almost entirely under water. At low tide, it will be almost completely exposed. Maritime grasses will border it at one edge.

Neither state nor federal regulatory agencies required such a habitat, Mr. Kane said, adding, “This was about doing something new.”

This is a perfect example of how small changes can transform a harsh urban environment into a hospitable habitat for native plants and animals. And it’s further proof that cities don’t have to be ecological wastelands. We can have our city and our nature, too.

(Thanks to Charles Waldheim.)

Resource Rich, Cash Poor

Joseph Stiglitz, the noted economist, writing at Slate:

On average, resource-rich countries have done even more poorly than countries without resources. They have grown more slowly and with greater inequality—just the opposite of what one would expect. After all, taxing natural resources at high rates will not cause them to disappear, which means that countries whose major source of revenue is natural resources can use them to finance education, health care, development, and redistribution.

I would say the United States and Canada are two examples of resource-rich countries that have escaped this quandary. But there are lots more that haven’t.

How far should you live from work?

Rush hour, New York City

Thirty minutes at most, according to the wisdom of the crowds.

That comes from reams of data and piles of research that suggests commute times tend to cluster around this point. People tend to be good at weighing their options, economists think. If you live farther from work, you can usually afford a bigger house or apartment. But there’s a point where that journey becomes too onerous, and you are willing to sacrifice some of those desires to live closer to your job. That point on average seems to be between 20 and 30 minutes.

I was inspired to look into this further after seeing an article by Charlie Gardner over at his blog, The Old Urbanist. Gardner had mined the American Community Survey for average commute times in major metropolitan areas. Though there was a tight correlation between population and commute time (metros with larger populations have longer average commutes), the differences weren’t pronounced. They ranged from a low of 22.5 minutes in Kansas City to a high of 34.6 in New York City. That’s not a lot.

But before we ask why commute times hover in a tight band, perhaps we need to ask why people commute so far in the first place. Why not work next door? The answers may seem obvious, but what’s readily apparent to one person may not be to another. That’s why we examine these things scientifically. Well, in this case your hunch is probably correct. An older study by Martin Wachs and his colleagues at UCLA found, unsurprisingly, that people choose where to live not just based on commute times but also neighborhood characteristics, schools, and safety.

Now we can move on to the more curious question, why commutes tend to average 20-30 minutes. It’s not just limited to the United States, either. In the Netherlands, the average commute time in the early 2000s was about 28 minutes. Many European nations average about 35 minutes. What makes a half-hour so universal in terms of commuting?

It didn’t used to be that way. Average commute times in 1980 were around 22 minutes. Today, they’re around 25 minutes. Three minutes may not seem like much, but remember it’s an average. To increase an average by that amount, some commutes had to grow significantly to counter those that shrunk or remained the same. Now, keep in mind there is a lot of variation about those averages. Some people travel 2 minutes to work, others well over an hour. But on average, they have increased.

What’s causing that lengthening is higher job densities in major metros. Job growth is requisite to economic growth, and vice versa. As metro areas add more jobs, those jobs tend to be concentrated in business districts (after all, not everyone can work out of their homes). And as business districts fill up, commute times lengthen because the roads leading there become more congested. So when the economy booms, traffic slows to a crawl. I heard anecdotal evidence of this when I lived in San Francisco. People told me, if you think traffic is bad now, it was much worse during the tech boom of the late 1990s. When all those tech workers lost their jobs, gridlock practically evaporated, they said.

Subtle changes in urban form may also cause longer commutes. One study in the Netherlands and another in Quebec, found that polycentric metro areas—those with two or more cities, like Minneapolis-St. Paul—tend to have longer auto commute times. As cities grow and begin bumping into one another, such agglomerations are likely to become more common. It’s possible commute times may increase as well. While there may not be consensus on this point, I haven’t found any studies that claim changes in urban form will shorten commute times. That makes sense if you look at somewhere like New York City, which is both monocentric and dense. People may work a short distance from their homes, but traffic is so congested and public transit makes so many stops that commute times are still relatively long. Simply increasing density in some cities may shorten commutes for a brief period, but the honeymoon won’t last forever.

Which is a bummer, because for the most part people think their commutes are too long. A survey of 2,000 commuters in the San Francisco Bay Area reported that 52 percent of respondents said they commuted at least 5 minutes longer than they would like. Among that group, median commute times were 40 minutes, which is certainly longer than the region’s average. On the other hand, 42 percent said their commutes were just right (their median time was 15 minutes). Surprisingly, 7 percent felt their commute was too short (median of 10 minutes). But despite the fact that a majority think their commute is too long, most people said they didn’t mind it, so long as their trips were less than 100 miles.

That people don’t mind their commute may be why commute times refuse to shrink. People in the Bay Area survey who didn’t mind their commute said they agreed with statements like, “I use my commute time productively” and “My commute trip is a useful transition between home and work”, which supports anecdotal evidence I’ve heard that people enjoy the separation between work and home. Twenty to thirty minutes may be just enough time to unwind.

It’s not entirely universal, though. Tolerable commute times seem to lengthen when people switch from cars to mass transit. People may find that time more productive, or maybe the time seems shorter because driving can be stressful, while just sitting usually isn’t. Personally, I know I’m willing to commute longer by train than car. Another reason is because mass transit commutes tend to be more reliable in terms of duration (at least for trains). Not having to worry about traffic jams doubling your commute is a big advantage.

Regardless of mode, people seem to settle on an ideal commute time. And once they have settled, they don’t seem to stray from it. A study of two metro areas in Washington State discovered that commute times don’t change much when people move or switch jobs. The thinking is that if a person gets a new job that’s farther away, they are more likely to move. Plus, as people have moved to suburbia, some jobs have followed. It’s a two-way street. But that doesn’t mean employers can move to the burbs without consequences. If an employer moves and an employee doesn’t move as well, the employee is more likely to find another job. Companies looking to relocate simply to cut costs may find the high turnover that results more costly in the long run.

Commuting is a big part of our lives, so it makes perfect sense that it would affect so much of the world around us, especially the cities we live in. Take a dense city like New York that has oodles of jobs, and lots of dense housing close in. That density helps keep commute times reasonable. But somewhere like Tulsa that doesn’t have as many jobs doesn’t have as much need for density. Form follows function, and currently the freeways in Tulsa are functioning pretty well compared with New York.

That presents a real dilemma for urban planners, who have been striving to increase densities in cities across the board. One approach has been mixed-use development that blends retail, housing, and office space. That may help reduce trip times for errands and such, but it doesn’t preclude people from living in one mixed-use neighborhood and working in another. The reality is, we’re probably not going to change commute times. If we offer faster and better transportation, people will use it until it becomes overburdened. At which point they’ll just move closer to work. Attempts to influence urban form through design may not have much of an impact if jobs don’t follow.

Sources:

Cervero, R. (1996). Jobs-Housing Balance Revisited: Trends and Impacts in the San Francisco Bay Area, Journal of the American Planning Association, 62 (4) 511. DOI: 10.1080/01944369608975714

Cervero, R. & Duncan, M. (2006). ‘Which Reduces Vehicle Travel More: Jobs-Housing Balance or Retail-Housing Mixing?, Journal of the American Planning Association, 72 (4) 490. DOI: 10.1080/01944360608976767

Clark, W.A.V. & Davies Withers, S. (1999). Changing Jobs and Changing Houses: Mobility Outcomes of Employment Transitions, Journal of Regional Science, 39 (4) 673. DOI: 10.1111/0022-4146.00154

Clark, W.A.V., Huang, Y. & Withers, S. (2003). Does commuting distance matter?, Regional Science and Urban Economics, 33 (2) 221. DOI: 10.1016/S0166-0462(02)00012-1

Giuliano, G. & Small, K. (1993). Is the Journey to Work Explained by Urban Structure?, Urban Studies, 30 (9) 1500. DOI: 10.1080/00420989320081461

Levinson, D.M. (1997). Job and housing tenure and the journey to work, The Annals of Regional Science, 31 (4) 471. DOI: 10.1007/s001680050058

Schwanen, T., Dieleman, F.M. & Dijst, M. (2004). The Impact of Metropolitan Structure on Commute Behavior in the Netherlands: A Multilevel Approach, Growth and Change, 35 (3) 333. DOI: 10.1111/j.1468-2257.2004.00251.x

Schwanen, T. & Dijst, M. (2002). Travel-time ratios for visits to the workplace: the relationship between commuting time and work duration, Transportation Research Part A: Policy and Practice, 36 (7) 592. DOI: 10.1016/S0965-8564(01)00023-4

Vandersmissen, M.H., Villeneuve, P. & Thériault, M. (2003). Analyzing Changes in Urban Form and Commuting Time∗, The Professional Geographer, 55 (4) 463. DOI: 10.1111/0033-0124.5504004

Wachs, M., Taylor, B., Levine, N. & Ong, P. (1993). The Changing Commute: A Case-study of the Jobs–Housing Relationship over Time, Urban Studies, 30 (10) 1729. DOI: 10.1080/00420989320081681

Photo by Jekkone.

Related posts:

Tell me how much you drive, and I’ll tell you where you live

Urbanites leave the car behind, but not as often as you might think

Drive a lot? Housing density may not be to blame

Overshoot Day

We know not everyone can live like Americans and not overextend our resources. Well as of today, August 22, we can’t live like anyone without going into resource debt. Overshoot Day happens every year. It’s when we’ve exhausted our annual global budget. From now to the end of the year, we’re living on borrowed resources. Yes it’s an artificial construct, but it’s illustrative nonetheless. 

(Via Peter Aldhous.)

Are insect colonies like cities?

A while back I covered research on sublinear scaling of various stripes, all related to population—hunter-gatherer home ranges (and why that means we’re prewired for density), place names and population density, and why mature forests have fewer, but larger, trees. Cities, too, follow a similar sublinear trend when it comes to infrastructure requirements for a given population. So does metabolism and body mass, which is really what got the whole sublinear scaling thing off to the races.

Now, Samuel Arbesman found another place where sublinear metabolic scaling rears its head:

More recently, this has been explored in cities, and it has been found that infrastructure and energy usage can scale sublinearly (larger cities have fewer gas stations per capita, for example), but productivity and innovation often scale superlinearly — we get increasing returns for patents and ideas in cities.

So the natural question is then, What about insect colonies? Insect colonies are in that weird liminal space between individual organisms and cities. Several years ago, a team of researchers set out to answer this question.

Head over to Arbesman’s blog for more.

Better Sidewalks Could Bring Improved Public Health

Well, that and 42 other changes like restricting smoking. But longer park hours and more attractive sidewalks and neighborhoods—to encourage walking and other forms of exercise—have additional benefits outside public health.

Why the Rich Don't Give

Nate Berg, writing at the Atlantic Cities:

In terms of charity, the rich in America give a lot. But they’re not giving the most. According to a new study out from The Chronicle of Philanthropy, which analyzes charitable giving at the ZIP code level, the richest neighborhoods are donating much smaller shares of their discretionary income than lower-income neighborhoods. Only nine of the 1,000 biggest-giving ZIP codes are among the richest 1,000 ZIP codes.

Commuters' limits

Charlie Gardner:

The data suggests that maximum mean travel time is somewhere slightly over 30 minutes, as indicated by the outlier example of New York, where most residents of the metro area apparently prefer to pay very high prices for housing rather than relocate to far cheaper, but more distant locales.

Sounds about right. Once a commute breaks the 30 minute mark, it starts to feel overly burdensome.

Update on the Membership Drive

How’s the membership drive going? Not bad. I’ve received some nice notes of support, and sign-ups have been moving along at a slow-but-decent pace. Still, they’re behind where I had hoped they would be, and if I stopped today I would be nowhere near covering my expenses (which do not include my time, only hosting and related costs). To be clear, I’m not looking to make a fortune off this site. That’s never been my goal. My goal has always been to cover important and interesting topics in a way that you’ll enjoy.

To those who have already signed up—a big thank you. Every time my inbox dings with a new member, I catch myself smiling. It means a lot. To those who are still on the fence, I hope I can convince you in the coming weeks that my efforts here at Per Square Mile are worthy of your support.

We’re 10 days away from the end of the membership drive. That gives you more 10 days to procrastinate. But it also means we’re more than halfway through. If there was ever a time to sign up to receive the member extras and a t-shirt, it’s now.

Is Simple Demography Behind Weak Economy?

David Leonhardt, writing for the New York Times:

Fewer people of working age means, obviously enough, fewer workers. It also means fewer potential entrepreneurs creating new businesses that hire people.

And aging isn’t the only demographic weight holding back the economy. For most of the 20th century, the share of women in the labor force was rising. It reached 60 percent in 1997, up from just 32 percent in 1948.

If you need confirmation of the impact of demography on the economy, just look at Japan.

New island in Pacific spotted by satellite

New volcanic island in the Pacific Ocean

Remember the floating mass of pumice spotted in the Pacific Ocean by a New Zealand Navy ship, the one that was presumed to be the sign of a new volcanic island? Well now a volcanologist and a NASA scientist have pinpointed its whereabouts by studying over a months worth of satellite imagery from the MODIS sensor. 

Natural ice dam

Natural ice dam, Perito Moreno Glacier

What you see above isn’t a Photoshop effect, and it’s not an artifact of the satellite sensor or an odd reflection of the sun. It’s the result of a natural ice dam created by the Perito Moreno Glacier in Patagonia, which is blocking the muddy waters of Brazo Rico on the left (the south, since the image is rotated) from the bluer Lago Argentino on the right (the north). Surreal, isn’t it?