Other Projects

d.w.rowlands [at] gmail.com

Although my formal academic background is largely in the physical sciences, I have a number of other interests as well. History in general interests me, but I'm particularly fascinated by the history of urban form and public transit and transportation in the United States. I occasionally write essays and do data visualization projects related to these topics. Since moving back to Prince George's County, Maryland after grad school, much of my writing has focused on the local history of the County and of the District of Columbia.

I also occasionally write articles on the transportation, urban planning, and history of the Washington, DC area for Greater Greater Washington, a DC-area urbanism website. Links to my articles can be found on my page there.


Washington, DC and Prince George's County, MD

Prince George's County Demographics and Transit

As part of an ongoing project for Prince George's Advocates for Community-Based Transit, I am collecting and presenting data about the current state of transit ridership and transit services in Prince George's County, Maryland. Our eventual goal is to propose service improvements for public transit in the county. However, we first need to develop a better understanding of the current situation. Below, I present four maps based on 2014 Census workforce survey data that illustrate demographic data about the County.

The Great Society Subway: A History of the Washington Metro, by Zachary M. Schrag

I first read The Great Society Subway, Zachery M. Schrag's definitive history of Washington, DC's rapid transit system, while I was an undergrad at Caltech. However, when I moved back to the Washington area in 2015, I decided that I should reread the book to get a better understanding of the history of the local transit system. This essay is a summary and review of the book.

PG Plaza: A Mall from the Space Age

While I was growing up in Prince George's County, I visited PG Plaza many times without thinking much about it. When I came back, after having been away for ten years and having learned a bit about the history of urban and suburban development, I realized that the site of the first encodes mall in Prince George's County contained quite a bit of interesting history.

Population Density, Race, and the Purple Line

This post is a quick analysis I did of a map of race and population density along the route of the Purple Line, a light rail line that is to connect the northern suburbs of Washington, DC.


Public Transit and Urban Design

A Comparison of "Subways" and "Rapid Transit"

This essay is a short introduction to the history of rapid transit systems in the US. In particular, it focuses on the difference between the pre-World War II subways and elevateds built in New York, Boston, Chicago, and Philadelphia and the "Rapid Transit" systems that were introduced starting in the 1960's to compete with automobiles for suburban commuters.

A Brief History of the T

This essay is a relatively short history of Boston's rapid transit and light rail system, which is collectively known to residents as "The T." It was originally written as notes for a class I taught as part of MIT's Educational Studies Program.

Populations of Large US Cities Over Time

New York, Philadelphia, and Boston have been among the larger cities in the US since the Revolution, although Boston and Philadelphia have lost ground to newer cities. Los Angeles, now the second-largest city in the country, didn't make the top ten until around 1900, a half-century after California was annexed, while New Orleans was already the sixth largest city in the country when it was purchased from France during the Jefferson administration, but now doesn't make the top ten. While it is well known that the relative populations of cities have changed with time, I thought it would be interesting to go through data from each decennial census to find out exactly how they have changed, and which cities were the largest during each census.


History in General and Other Topics

The Origins of the Constitution

This essay consists of an expansion of notes that I wrote for a two-hour class on the Constitutional Convention that I taught through the MIT Educational Studies Program.

Coin of the Realm

As a child, I was always curious what the names of currency "meant." A dollar was a green piece of paper you could use to buy things, but why was it called a "dollar," anyway? As I got a bit older, I began to wonder about the currency names used in other countries: it made sense that many former British colonies might call their currencies the "pound" or "shilling," and even that Canada might use a "dollar" due to its proximity to the US. But why would Australia, a former British colony on the other side of the Pacific from the US use the "dollar" as well? Here, I've created a map of currency names with shared etymologies, many of which are somewhat surprising.

States by Fraction of the US Population

It's well-known that the populations of US states have changed with time, both in absolute terms---there were only about three million people living in the Thirteen Colonies at the time of the Revolution---and in relative terms. However, the relative populations of states at different points in time are less well known, so I thought it would be useful to create this graphic showing how the relative populations of US states have varied in each decennial census.