The Petermann Iceberg

There's a big story in the news today about an iceberg that has broken away from the Petermann Glacier in Greenland. These things are always compared to real places in order to provide context and this case is no different. The BBC reported that the iceberg is 'twice the size of Manhattan'. This is big, but exactly how big is it? It's roughly 100 square miles. That's the same size as Edinburgh. But how big is that? To answer these questions I've just modified an earlier image based on the size of UK cities (local authority boundaries) to put it in context. Put simply, this iceberg is bigger than Bristol, it's bigger than Cardiff, it's bigger than Manchester. It's just big. Click the image below to see for yourself.

Population Density in New York City

In some recent posts I've been looking at the issue of population density. I did this for London in December and for the continental United States earlier this month. Given the extremely high population density in Manhattan, I thought it would make sense to take a closer look at New York City. So, I took some publicly available NYC GIS data, some 2010 US Census data and went to work. The result is the 3D map image below...

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The mapping here is done at the Census Tract level, of which there are about 2,100. These areas have an average population of about 4,000 though there is some considerable variation between areas in that several tracts contain more than 10,000. The spatial patterns above are fairly obvious and, as expected, Manhattan dominates once again. However, the individual Census Tract with the highest population density is actually in Corona, Queens with a figure of 216,000 persons per square mile*.

There's a lot more information on New York City's 2010 Census results on these pages, from the New York City Department of City Planning...

* N.B. It's important to point out here that these areas are much less than a square mile, but I'm using square miles since it is a conventional measure of population density in urban areas).

Daytime Population in the United States

My last post on London's Daytime Population is getting a lot of page views, which is nice, so I thought I'd do something else on the same topic. Although I do try to make nice images with data, there are some very important planning-related issues here. The first is just to do with the importance of knowing how many people live in an area. In New York City, the city challenged the 2010 results because it could have led to less federal aid, and in the UK in 2011 the city of Cardiff claims there was an undercount which could have led to them missing out on £85 million of funding since 2001. In relation to daytime population, this is also very important, but more difficult to calculate, as Robert C. Schmitt discussed in 1956. So, I looked at the 3,111 counties of the lower 48 states in the US and mapped them by daytime population density, as you can see below.

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Why does it matter that we know what the daytime population of a place is? Well, there are many reasons including planning for public transit, traffic flow, infrastructure needs, utilities and even for developing evacuation procedures (Schmitt was writing in 1956 but perhaps this last point is still relevant today).

In the United States, the county with the highest daytime population density is New York County (aka Manhattan). It is far and away the leader in this category, with 126,100 persons per square mile. That doesn't quite match the daytime population density of the City of London but bear in mind that Manhattan covers 22 square miles! Manhattan's daytime population is also about 1.3 million more than its total resident population, which in 2010 was about 1.6 million.