More urban LA, SF, DC, Philly, and Boston?

[OyCrumbler]

Originally Posted by Trafalgar Law

I already spoke with a moderator prior to resurrecting this thread. I inquired if I could bring in a few extra cities to this discussion and go with some visuals from the tool that I'm using. I was told that should be fine as long as forum guidelines are met.

This thread is like 8-9 years old, the original premise has already run its course, which is why it has over 2,000 posts and the OP that created this thread is long gone and has been gone for years. The forum encourages us to reactivate threads and reuse them to engage in topics that we have an interest in instead of creating a new thread altogether.

So I did my due diligence and got the okay to do this, that includes bringing in New York and Chicago into the fold in this discussion. I say all of that to say the Chicago versus San Francisco discussion that's taking place now is appropriate for this thread.

You can see the changes in Chicago and San Francisco over a fixed period of time here: https://pudding.cool/2018/10/city_3d/

Regarding the 10 square mile urban core discussion. I actually think 10 square miles is a decent size for an urban core of the city; for an American city it may actually just be on the small side of things. Though I understand where you're coming from, elsewhere in the world it may just be far too large. Certainly in the more condensed Asian and European cities that's the case but I don't think the same rule would apply to the American cities. American cities are physically much larger and oftentimes built in a more spread out manner than their counterparts elsewhere, they don't have the same tightly knit structural form, save for a few exceptions. With that said, I personally think of 20 to 25 square miles to be close to optimal size for an urban core area for an American or Canadian city. Think of it this way, say a city is 100 square miles then 10 square miles of an urban core represents 10% of the city's footprint and 20-25 square miles represents 20-25% of the city's footprint. I think both instances are appropriately sized. Majority of the major cities in the United States that we discuss in topics like these also happen to exceed 100 square miles in land area, some of them are multiple times the size. Only a small handful of the cities are physically contained to a smaller frame: Boston, Miami, San Francisco, and Seattle. Even in the case of these cities they have adjacent municipalities that are extensions of their urban fabric. So even though on paper they are physically small (or at least smaller than 100 square miles) in reality they actually exceed that size when accounting for those adjacent communities.

In that essence, I think 20 to 25 square miles or even 10 square miles as a representation of a city's urban core is a good bet. It works for the American cities even though it may physically be too much ground to cover for numerous cities in Europe or Asia that are built in a more condensed and space-limited manner. Just my thoughts on it, I can understand if you see things differently. It is sort of a subjective premise to begin with, so it leaves a lot in the open for discussion. Just to clarify my point and summarize, for a 'downtown' I think 2-3 square miles is plenty big enough; for a "greater downtown" I think 5 square miles should be the top-out size; for an urban core I think anything from 20 to 50 square miles can be appropriate but it depends on how large the physical city is. For example, in a city like New York that is 340 square miles or so, 50 square miles would be appropriate for an urban core. Essentially it's all of Manhattan and the most dense and urban sections of Brooklyn and/or Queens adjacent to the riverfront. For a city like Miami, I think 25 square miles is an appropriate representation for the urban core, so it would be everything east of 924/959 (roadways) and would include the barrier island communities, possibly north into Aventura as well.

I don't myself mind if those cities are brought in--only that this topic did specifically cite them though good on you for checking with the mod. 10 square miles can be fine, but it very much changes what the nature of what the city is encompassing is compared to 20 to 50 square miles or 2 or 3 square miles. A lot of actual CBDs for the more urban cities are quite small even if some of them like the Downtown LA moniker officially encompasses more area, the actual large CBD skyrise district with a lot of of commercial office is far less than 10 square miles. Anyhow, I so like setting out a fixed square mile as that is often better apples to apples comparison. Like I said in the rest of the post you quoted, there's a fair chance that 10 square miles of downtown Chicago, downtown Brooklyn, and North Brooklyn / LIC have greater daytime density than 10 square miles of the northeastern quadrant of San Francisco.

[MarketStEl]

Originally Posted by Trafalgar Law

I already spoke with a moderator prior to resurrecting this thread. I inquired if I could bring in a few extra cities to this discussion and go with some visuals from the tool that I'm using. I was told that should be fine as long as forum guidelines are met.

This thread is like 8-9 years old, the original premise has already run its course, which is why it has over 2,000 posts and the OP that created this thread is long gone and has been gone for years. The forum encourages us to reactivate threads and reuse them to engage in topics that we have an interest in instead of creating a new thread altogether.

So I did my due diligence and got the okay to do this, that includes bringing in New York and Chicago into the fold in this discussion. I say all of that to say the Chicago versus San Francisco discussion that's taking place now is appropriate for this thread.

You can see the changes in Chicago and San Francisco over a fixed period of time here: https://pudding.cool/2018/10/city_3d/

Regarding the 10 square mile urban core discussion. I actually think 10 square miles is a decent size for an urban core of the city; for an American city it may actually just be on the small side of things. Though I understand where you're coming from, elsewhere in the world it may just be far too large. Certainly in the more condensed Asian and European cities that's the case but I don't think the same rule would apply to the American cities. American cities are physically much larger and oftentimes built in a more spread out manner than their counterparts elsewhere, they don't have the same tightly knit structural form, save for a few exceptions. With that said, I personally think of 20 to 25 square miles to be close to optimal size for an urban core area for an American or Canadian city. Think of it this way, say a city is 100 square miles then 10 square miles of an urban core represents 10% of the city's footprint and 20-25 square miles represents 20-25% of the city's footprint. I think both instances are appropriately sized. Majority of the major cities in the United States that we discuss in topics like these also happen to exceed 100 square miles in land area, some of them are multiple times the size. Only a small handful of the cities are physically contained to a smaller frame: Boston, Miami, San Francisco, and Seattle. Even in the case of these cities they have adjacent municipalities that are extensions of their urban fabric. So even though on paper they are physically small (or at least smaller than 100 square miles) in reality they actually exceed that size when accounting for those adjacent communities.

In that essence, I think 20 to 25 square miles or even 10 square miles as a representation of a city's urban core is a good bet. It works for the American cities even though it may physically be too much ground to cover for numerous cities in Europe or Asia that are built in a more condensed and space-limited manner. Just my thoughts on it, I can understand if you see things differently. It is sort of a subjective premise to begin with, so it leaves a lot in the open for discussion. Just to clarify my point and summarize, for a 'downtown' I think 2-3 square miles is plenty big enough; for a "greater downtown" I think 5 square miles should be the top-out size; for an urban core I think anything from 20 to 50 square miles can be appropriate but it depends on how large the physical city is. For example, in a city like New York that is 340 square miles or so, 50 square miles would be appropriate for an urban core. Essentially it's all of Manhattan and the most dense and urban sections of Brooklyn and/or Queens adjacent to the riverfront. For a city like Miami, I think 25 square miles is an appropriate representation for the urban core, so it would be everything east of 924/959 (roadways) and would include the barrier island communities, possibly north into Aventura as well.

After parsing this, I wonder what distinction you're making between "downtown" and "urban core."

I'm guessing you are distinguishing between the empties-out-at-5-pm office district and the dense(r) residential districts adjacent to this district.

The thing is, in most of our older cities, the line between these two districts is blurred, and that was even before we started converting older Class B/C office buildings into apartments and condominiums.

I would generally include both the office and residential districts in the "downtown" and treat that as synonymous with the "urban core."

But then again, where I live, the organization whose mission is to promote the urban core speaks of "greater Center City," which is a district that includes dense residential districts I would not place "downtown" - nor would anyone else. This city does have the virtue of having a geographically well-defined "downtown" whose boundaries everyone agrees on - they're the boundaries of the original town Thomas Holme laid out for William Penn in 1682. This area includes both an office/shopping district and a residential zone, the latter home to the third-largest "downtown" residential population in the country, or so it's commonly claimed. The areas to the north and south of this - and increasingly, to the west, where two large universities are next-door neighbors - are now tied to this "downtown" but not part of it.

That's what you were getting at, right?

[Trafalgar Law]

Originally Posted by MarketStEl

After parsing this, I wonder what distinction you're making between "downtown" and "urban core."

It's more of a structural hierarchy that I've devised for myself to assess North American cities (well just the American and Canadian ones; Mexican cities may be formatted differently so it wouldn't work out).

My system is a lot like measurement units.

At the very bottom you have millimeters, well technically micrometers but we'll ignore that and start with millimeter and move our way up.

So basically 10 millimeters translate into 1 centimeter; then 100 centimeters translate into 1 meter; then 1,000 meters translate into 1 kilometer.

Likewise for me at the very heart of it all you have the CBD, or as I like to call it "the bare bones" because it's essentially just a workplace environment with little residential activity to speak of. In American and Canadian cities, this is referring to simply the business district where the offices are, maybe a few residential components if they're thrown into the jungles of the CBD with the office buildings. So the first unit we have is the CBD, just the bare bones, in other words just the offices and some residential that may be in the mix with offices. Then expanding outward from that, the CBD eventually goes to form "Downtown" and my interpretation of "downtown" is the CBD and only the residential neighborhoods attached to it on each side. Beyond "downtown" you have "greater downtown" which then begins to encapsulate an even larger area. This "greater downtown" for all intents and purposes is the "downtown" plus the neighborhoods encircling it and for all intents and purposes lets give it a hard limit to be practical. Lets say that "greater downtown" never goes beyond 5 or 6 square miles in total size for any city in Canada and the United States. Then as we begin to move even further outward from that the "greater downtown" gives way to what I call the "urban core". The "urban core" is a significantly larger area, several times the physical size of the previous unit, which was "greater downtown". Beyond the "urban core" is the city-proper in all of its wholesome.

So now lets apply some numbers to make it easier to explain but first we should assign a test subject. For all intents and purposes lets call the test subject City X. We'll start from the most basic unit and move out way up, giving specifications on size and population each step of the way.

- The first unit is City X's CBD. Lets say that City X's CBD is about 0.5 square miles, which is roughly about right for simply just the office component for most cities. In those 0.5 square miles the CBD has 55,000,000 square feet of office space, a workforce population of 120,000 people, and a permanent residential population of 9,000 people.

- Now moving beyond City X's CBD comes City X's "downtown". Lets say that City X's downtown is about 2.0 square miles, which is par for the course for American cities. In those 2.0 square miles it includes the CBD with all of the specifications we outlined about the CBD in the point directly above this plus all of the attached residential neighborhoods connected to each of its sides. So the overall statistics for City X's downtown would still be about 60,000,000 square feet of office space (expanding a little bit out from the CBD ended up absorbing an additional 5 million square feet of office space), a total workforce population of 135,000 people (expanding beyond the CBD also ended up adding another 15,000 employees), and a total permanent residential population of 45,000 people (expanding beyond the CBD substantially increased the residential population, over four-fold).

- Next lets move beyond even that to the next unit, which is City X's "greater downtown". For all intents and purposes lets presume that the specifications of City X's "greater downtown" entails a land area of 5.0 square miles, which is about right for most major cities in the United States and Canada. In those 5.0 square miles the "greater downtown" includes the "downtown" which in turn includes the CBD. So the allocated specifications come out as follows, the "greater downtown" in totality has 85,000,000 square feet of office space, a workforce population of 240,000 people, and a total permanent residential population of 115,000 people. At every level that we've covered here the "greater downtown's" statistics simply dwarf the previous unit entirely by magnitudes.

- We're not done though. Next we're moving on up to the next unit, which is City X's "urban core". The "urban core" is an expansion of the area and includes even more territory and greatly expands the scale and scope of the city's urban fabric. Now lets add some numbers and specifications to it as it absorbs even more adjacent urban neighborhoods into the fold. City X's "urban core" includes the "greater downtown", which in turn includes the "downtown", which in turn includes the CBD. City X's "urban core" is 25 square miles, which is typical of North American cities. In those 25 square miles it includes 275,000,000 square feet of office space, a workforce population of 360,000 people, and a total permanent residential population of 450,000 people. Like each step before this, the greatly expanded area exhibits a substantial boost in the numbers and statistical specifications.

- Beyond the "urban core" is City X's city-proper boundaries but for all intents and purposes we're not going to concern ourselves with this one because it goes into the further out regions of the city and ends up becoming more suburbia than urban fabric. Just for the sake of clarity though we'll give City X definite specifications. So lets say that City X's city-proper boundary is 100 square miles, with a total of 300,000,000 square feet of office space, a workforce population of 450,000 people, and a total permanent residential population of 750,000 people.

This is all subjective but this is how I usually layer up American and Canadian cities. For most major cities, especially the ones with legacy style build-outs, a 25 square mile core would still exhibit a very urban form with very few, if any, leafy low density suburbanized areas. It does however include nearly every key feature of the city including the city's most prominent amenities and services; meaning the best restaurants, best stores, best libraries, best offices, best transit coverage and all of that is found here. In other words, moving beyond City X's "urban core" area, the level of transit will drop, the urbanity will decrease, the office space will become more sparse, the population density will mellow, and the housing stock will change to allow a less urban built format.

This is merely an example, the actual size of a city's "urban core" directly relates to the actual physical size of the city. For example, for a city of 100 square miles, the urban core could very well just be 25 square miles (or a little bit more) and beyond that will be a lot of suburbia, often dense suburbia because it is inside the city proper but suburbia nonetheless. For a city that is like 400 square miles in land area, then the urban core could end up being 75 square miles or even a tad bit more.

Here is a sloppily put together edited image to display all of that (I'm not the artistic type, so its pretty bad editing on my part):


I used Denver as a play-in for City X. Denver is a prototypical American city, with the standard street grid, and an entirely American framework to urban planning without any of the random quirks like Atlanta or Boston's non-grid format (though both do have some grid format in some parts), Houston's no-zoning (though Houston does operate with ordinances), New York's decentralized borough system (though it hasn't stopped New York from reaping the benefits of centralization), so on and so forth. Plus it's inland and not surrounded by any massive bodies of water, therefore it expands outward on every side, thus making it a perfect test subject for this little experiment.

[MarketStEl]

Trafalgar Law: Okay, that makes sense. Thanks for the explanation.

Some urban geographers express a similar idea with the notion of a 1-, 2- and 5-mile radius of City Hall. Since most US cities have their city halls at or near the center of the CBD, the territory thus described closely matches your CBD, downtown and urban core (skipping the greater downtown).