I just discovered this set of maps (via Brian Potter) looking at the largest cities in the world from 100 CE all the way through to today (well 2015 CE). Here are what the two bookends of this map series look like:

It is an interesting reminder of just how centralized the world was around the Mediterranean and parts of Asia, and also how nothing is guaranteed. As recent as 1900, cities like Manchester and Philadelphia were among the top 10 largest cities. Today they aren't even close.

For the full map collection, click here.

UPDATE: The data behind these maps has been called into question. Look out for a follow-up post.

Urban environments can be dense in many different ways. This is a topic that we have discussed on several occasions here on the blog. But this working paper by Solly Angel, Patrick Lamson-Hall, and Zeltia Gonzales Blanco -- called The Anatomy of Density -- is a more scientific way of looking at it. They have come up with six measurable factors that, when combined, define urban density.

What this means is that cities achieve urban density through different kinds of built form. Hong Kong, for example, gets its density from height, even though only about 4% of its land area is occupied by residential buildings. Dhaka, on the other hand, does it through low building heights and high residential coverage. Homes occupy about 20% of the city's area. Another dimension is crowding.

But here's something that may surprise you. Most cities are actually becoming less densely populated. And, despite our best efforts to encourage more sustainable forms of development, sprawl has continued to outpace densification in the vast majority of the urban agglomerations that were studied as part of this working paper. The wealthier we become, the more space we want to consume.

Here's a graph from The Economist that speaks to this trend:

To download a copy of the working paper, click here.

Image: The Economist

Earlier this month The Washington Post published an article called, There’s no such thing as a city that has run out of room.

And what it was really about was that when we say there’s no more room (I guess people are saying this), we are really saying that we just don’t want to allow anyone else to become our neighbor. Because the reality is that urban population densities vary widely around the world. So how can you really call a place full?

I’m not sure I feel this pain point as much as the author, but I always find population densities to be a fascinating topic. And accompanying the article was a tool – using data from Demographia – that allowed you to compare the population densities of various cities.

Here are are two scenarios I ran:

It’s important to keep in mind that these numbers are averages for the entire economically contiguous region. So it tells you nothing about the potential spikiness of certain areas. That’s why the population density of New York (which includes portions of New Jersey and Connecticut) probably seems low to you.

Still, it’s fascinating to see how extreme some cities – including some first world cities like Hong Kong – can be. Clearly many cities have a lot of room to become a lot more dense. And I think that would be a good thing.

I just discovered this set of maps (via Brian Potter) looking at the largest cities in the world from 100 CE all the way through to today (well 2015 CE). Here are what the two bookends of this map series look like:

It is an interesting reminder of just how centralized the world was around the Mediterranean and parts of Asia, and also how nothing is guaranteed. As recent as 1900, cities like Manchester and Philadelphia were among the top 10 largest cities. Today they aren't even close.

For the full map collection, click here.

UPDATE: The data behind these maps has been called into question. Look out for a follow-up post.

Urban environments can be dense in many different ways. This is a topic that we have discussed on several occasions here on the blog. But this working paper by Solly Angel, Patrick Lamson-Hall, and Zeltia Gonzales Blanco -- called The Anatomy of Density -- is a more scientific way of looking at it. They have come up with six measurable factors that, when combined, define urban density.

What this means is that cities achieve urban density through different kinds of built form. Hong Kong, for example, gets its density from height, even though only about 4% of its land area is occupied by residential buildings. Dhaka, on the other hand, does it through low building heights and high residential coverage. Homes occupy about 20% of the city's area. Another dimension is crowding.

But here's something that may surprise you. Most cities are actually becoming less densely populated. And, despite our best efforts to encourage more sustainable forms of development, sprawl has continued to outpace densification in the vast majority of the urban agglomerations that were studied as part of this working paper. The wealthier we become, the more space we want to consume.

Here's a graph from The Economist that speaks to this trend:

To download a copy of the working paper, click here.

Image: The Economist

Earlier this month The Washington Post published an article called, There’s no such thing as a city that has run out of room.

And what it was really about was that when we say there’s no more room (I guess people are saying this), we are really saying that we just don’t want to allow anyone else to become our neighbor. Because the reality is that urban population densities vary widely around the world. So how can you really call a place full?

I’m not sure I feel this pain point as much as the author, but I always find population densities to be a fascinating topic. And accompanying the article was a tool – using data from Demographia – that allowed you to compare the population densities of various cities.

Here are are two scenarios I ran:

It’s important to keep in mind that these numbers are averages for the entire economically contiguous region. So it tells you nothing about the potential spikiness of certain areas. That’s why the population density of New York (which includes portions of New Jersey and Connecticut) probably seems low to you.

Still, it’s fascinating to see how extreme some cities – including some first world cities like Hong Kong – can be. Clearly many cities have a lot of room to become a lot more dense. And I think that would be a good thing.