New York

Biblio (113) The rise and fall of Manhattan’s densities

biblio 113- Manhattan densities

This working paper by Shlomo Angel and Patrick Lamson- Hall, researchers at the Marron Institute at NYU, studies the evolution of population densities in the built-up areas of Manhattan from 1800 to 2010. They combine census data for population with a series of maps, and conclude that time is ripe for a densification programme that could accommodate a larger population with bottom-up actions, without need to use large public- financed schemes. The proposal is essentially a change in the planning regulations that would allow higher densities in peripheral boroughs, as was done before in Manhattan. This would hardly be seen as a contentious issue where I live, as the habit of living in denser neighbourhoods is more common, but would mean a change for many in the land of the single- family home; even if skyscrapers are not a rarity, high rise housing has different cultural implications, as you would loose many freedoms you have being the lord and king of your lot.

There are two interesting videos which show the base data that helped reach those conclusions

Biblio (95) Rebuild by Design

Rebuild by Design is an initiative of the US Department of Housing and Urban Development (HUD). Even if sometimes from Europe such a ministry seems unlikely for the US, it has existed for decades, with influential policies, although not always on the good sense… as everywhere. HUD is looking for a way to tackle the urban resilience challenge posed by climate change, taking into account the Sandy lessons. These lessons can benefit other rebuilding efforts or risk prevention schemes. The initiative has formalized as a competition whose results were published in April, with 10 winners proposing alternatives for damaged coastal cities. There are big names from the architectural world, as OMA, but the projects are not just drawings, as they benefit from public participation; according to the available information, what is really chosen is not a team of architects, but local coalitions that have built consensus and will receive grants to develop proposals that have been formalized by specialists.

Maps 2014 (13) Walk NYC

Here is a map that (apparently) can only be consulted in the streets of New York. The classical pedestrian map, that lets you find your way, has been subject to an interesting approach in the American context, as in NYC people walk. From the way maps are oriented (not always with the north up, but taking into account the position of the beholder) to the design of the icons, an elegant work by Pentagram.

Maps 2014 (10) Home price mapping in France and America

Map by

Map by

There are three main ways to get data on real estate prices: conducting a study based on standard assumptions (usually comparing with neighbouring properties is factored), using listing prices or using the amount that the legal professional authorised by the Government to record the deed. This legal professional is a Civil Law Notary in civil law countries as Spain or France, or their former colonies. The third way is, assuming there is no tax cheat, the most precise, but it is not universally available, or its geographical detail is not of use; for instance, in Spain the General Notaries Council ( publishes data by province. The geographical scope is relevant, as the real estate values depend a lot on location, and mixing in the same bag high price neighbourhoods with low price exurbs results in meaningless averages.

In France notaries ( do publish data with a detailed geographical scope (census blocks). This  is good to understand recent activity. But a substantial part of the land has such a reduced amount of sales that data is not representative (or simply does not exist, just think of depressed rural areas with no sales for years). This does not prevent the fact that there is a demand for some kind of data, so it is estimated by a multifactor system, in which listing prices and realtors opinions are factored (

In the US the fact that there is a continental size nation with 50 legal systems has led to nationwide portals as, which estimate prices for a substantial part of the country, even if a large part of the central states, as Texas or Louisiana, are not rendered.

Taking as a reference data from, and for Paris, New York and Madrid, with an exchange rate of 0,72 € by $, and considering that 1 sq m is equal to 10,7 sq ft, you can see that the more expensive areas of Paris (rue du Bac, for instance) are over 14.200 €/sq m, those of Madrid (Recoletos) are around 11.000 €/sq m, and those of New York (Flatiron District) are in the region of the 16.000 €/sq m. Any need for more reasons to understand why the urban fabric of the core areas of successful cities has such an inertia?.

Map by

Map by

Biblio (77) Parking in New York

biblio 77- parking NY

The NYC Department of City Planning has just published an inner ring residential parking study examining all the complexities of that issue. The study focuses on a set of neighbourhoods in which the zoning rules require residential parking, but which have potential for a reduction by improving other transportation modes. The potential for an evolution is acknowledged.

Tokyo: the size of the core


Tokyo presents itself as the biggest metro area in the world, with over 35 million residents. But as nearly any metropolitan area, it has a core. And that core says some things about how the city is, even more if you compare it to cities you know.

Tokyo’s core is marked by the bay, which is becoming more difficult to see as it is being filled for new urban uses, by the mouths of several rivers, the presence of the Imperial Palace and a motorway system that is much more apparent and ramified than in European or even American cities.

The Fifth Avenue

Fifth avenue BID: 1,2 km of central street. The red outline is that of the BID.

Fifth avenue BID: 1,2 km of central street. The red outline is that of the BID.

The fifth avenue is very, very long; avenues in Manhattan go from north to south in the island, and this is longer than 10 km. Along this distance there are many neighborhoods and diverse settings, and here I’m interested in the Fifth Avenue Bussiness Improvement District, one among a series of such public- private partnerships for the maintenance and retail promotion. Other parts of the avenue are included in BIDs, but this one is the most iconic for the image this street conveys to the world.

The BID encompasses a section of 1,2 km of the fifth avenue and a variable depth on lateral streets; for instance, the Rockefeller Center, drawn on the upper map with a hatched black rectangle, is not completely into the BID, while the 57th st section goes from Madison Avenue to the Sixth. This shows that the perception of space and its influence areas by retailers is adapted to specific factors, not related to geometric regularity.

Fifth avenue is slightly more that 28 m wide. There are three lanes in a single direction (towards downtown) and a bus lane. This leaves 6 m sidewalks. No doubt, this street is associated usually to luxury, but sidewalks are of concrete, without great detailing, but for some tree grids (there are few trees) as those of the Rockefeller Center. There are also remarkably few underground infrastructure access plates.


alcorque rockef aceras fifth

Maps (5) Old Manhattan

The island of Manhattan has been repeatedly described. In this case I would choose the proposals in the book “The Iconography of Manhattan Island 1498-1909”, by Stokes, Paltsits and Wieder, that you can download from (note this is a 73,5 Mb download). The content is not limited to maps, but there is also an interesting collection of historical vistas that illustrate the evolution of the urban fabric. I would choose two images:

NY- concesiones originales

The map of the original patents or ground briefs, with the farms outlined, on the southern point of Manhattan, what is today known as wall street.

NY 1848

The view from the roof of Trinity Church in 1848, which shows a city that is still European for heights and general layout.

Maps (1) Sandy storm

Please consult the original map on

Please consult the original map on and read the full story there

A good example of an elegant and simple map whose reality everyone wishes could have been avoided: deaths in low lying “bowls” due to the Sandy Storm in Staten Island, New York City. A simple map, with the level contours and the dots (see the link) where these people died, with their names.

Density in Madrid (6) Gaztambide


Dens madrid-6- Gaztambide

2001:285 dwellings per hectare

2013: 291 dwellings, 462 people per hectare

Gaztambide was in 2001 the barrio with the highest residential density (dwellings per hectare) in the Madrid Municipality; in 2012 it was the third densest in terms of residents per hectare, after Embajadores and Pacífico. But it is not an area filled with towers; it is simply a zone in which there is almost nothing but dwellings (and a sizeable retail presence, mainly on the ground floors); it is a socially fashionable area of the city. The dwellings have sometimes the limitations of the XIXth century Ensanche, that has been densified to the extreme, so sometimes the corridor in your house has a larger area than most rooms, and some rooms have scarce light and air; but it is a posh area, as far as central Madrid goes (almost on par with the Barrio de Salamanca).

The southern limit is the Alberto Aguilera Street, having as a beacon (as much socially as in terms of bulk) a branch of El Corte Ingles department stores (A), which helps dinamize the Princesa Street (A-C), also served by the large Intercambiador de Moncloa, (C) a subway/bus exchange platform giving acces to the northwest sprawling suburbs. The western flank (C-D) is the interface of the XIXth century grid (here mostly built during the XXth century) with the Ciudad Universitaria and its green spaces. To the east and north the limits are with a similar grid tissue. The high density you find is subjet to variations: you can find an experiment on housing innovation from the first third of the XXth century, the Casa de las Flores, by Secundino Zuazo (B, on the left on the aerial image), with an interesting recent building on the block inmediately to the north that opens diagonally the block courtyard to the street, and you can also find what simply are extreme excursions into density (E).

The Bercy block

The Bercy block

What do 290 dwellings per hectare mean, when compared to other urban tissues? in Paris it could be compared to the ilot Pommard- Renoir in Bercy, always taking into acount that the references in Habitat- formes urbaines (page 178) are to the city block, so they are somewhat higher than in a neighborhood, albeit not that much in one with such lack of public spaces as Gaztambide. On the other side of the Atlantic, according to the 2010 census the island of Manhattan has slightly over 842.000 housing units on an area of 8.746 hectares, so the average is close to 100 dwelling units per hectare… It might seem surprising, but just take a look at the size of Central Park when related to the total island, and how the areas out of downtown and midtown have lower heights, and, above all, the fact that many skyscrapers are offices, not homes…

A view of Manhattan by blueridgekitties. You can access the full image on

A view of Manhattan from the west, with Central Park, by blueridgekitties. You can access the full image on

The most common appartment size range in Gaztambide in 2001 was 91-105 sq m, with an average of some 80 sq m , so below the Bercy block, and higher than the average in Manhattan.

All this will surely lead my fellow architects to rise their hands and ask: well, but what about built density, as floor/area ratio, including the complexity of other uses beyond housing? That will be the subject of future posts…