Why It Matters Urban Islands
Summary
We have determined whether a postcode falls within an area which is geographically isolated or cut off from the surrounding urban environment. These areas are called ‘Urban Islands’ and may be cut off from the surrounding urban environment by large roads, train tracks, rivers or other impenitrable boundaries.
Interpretation
| Dataset | Explanation |
|---|---|
| Urban Island (yes/no) | This tells you whether or not part of your postcode falls within an urban island. |
| Urban Island Distribution | If your postode does not fall within and urban island you can view the overall distribution of urban islands on the map. |
Definition
An Urban Island (“UI”) is a parcel of land that is bound on all sides by hard boundaries (see further explanation below) meaning that they are impenetrable on foot. The hard boundaries may be punctuated by 1 or 2 access points which can be crossed on foot (3 at a maximum on large island sites) however, these access points must be separated by a walk that is over 12 minutes by foot which equates to 1km in distance.
Why the metric matters from a commercial inhabitant’s perspective
Living in a locale that falls within a urban island can impact residents: (1) functionally, in terms of how easy it is to move around their neighbourhood with public or private transport; (2) economically as homes within urban islands are more acutely subject to the pricing implications of supply constraints especially with urban islands that host unique desirable characteristics within the housing market; and (3) socially, as the shared communal identity associated with each and every neighbourhood is found to be more pronounced where its physical boundaries are more easily identifiable.
As a consequence of the entry and exit points to a UI being more limited in number as compared to in other neighbourhoods, it follows that if vehicular use is high in surrounding areas, residents within UIs, crossing the UIs boundaries, may experience high levels of traffic, especially in peak travel periods.
Residents may also find that homes within UIs carry an economic premium since the same hard boundaries, that create the island effect often, serve as constraints on development sprawl which manifests itself in two ways. Where the UI hosts features, which are considered as desirable such as visually pleasing natural ecological/natural capital or a prestigious educational institution, then competition to reside within the UI will cause rental and purchase prices to rise. The downside to this is that should development intensify without the additional educational, medical and social infrastructure needed, the island effect will have the opposite effect creating less desirable “ghettos” where prices within the UI would be lower than in comparable proximate areas.
The social effects of living within an UI may also manifest themselves in resident’s social networks. There is good evidence to suggest that due to often stronger feelings of community caused by the island effect, residents within a UI will have less geographically disparate social networks and a greater sense of feeling like they belong to a community.
Why the metric matters from a residential inhabitant’s perspective
Commercial properties in highly coveted UIs are subjected to the same economic dynamics as residential properties. The limited supply may drive prices upwards when the UI hosts desirable characteristics. Since UIs are also relatively secluded from the rest of the city, physical exposure to a broader and diverse audience is relatively limited and highly divergent between the internal areas and the entrances. Tailoring the offered products and services to the islanders’ tastes will offer a unique opportunity to maximise revenue and make the most out an almost monopolistic location.
Presence within a prestigious UI can also have validation and community membership benefits. Think, for instance, about the concentration of banks in Canary Wharf. While the character of UIs is highly diverse, the physical access constraints can deter those businesses reliant in heavy traffic or on drawing their workforce from surrounding areas. When it comes to understanding a locale, the UI metric in combination with others, such as income and use, offer a good balance of physical and socioeconomic variables. Despite many exceptions, while higher-income areas tend to sustain a higher diversity of businesses and uses, lower-income UI tend to become single-use dormitory areas. Eventually, UIs result in the contention of social and economic patterns and behaviour to particular areas.
Crouch End is an example of an Urban Island (Photograph: Chris Whippet, geograph.co.uk)
General commentary
A UI in essence only means one of 3 things. Firstly, it may restrict the supply of developable land. A hard boundary that is not easily redrawn can lead to a village effect as a UI is protected from overdevelopment. In this respect, UIs define the location of future urban development which may alter a current location. However, a UI that does not constrain the supply of developable land is unlikely to increase land prices.
Secondly, the hard boundaries also limit spill over effects of social and economic phenomena. For example, a UI may reinforce particularly lower or higher property prices in a given area. The same goes for settlement patterns of companies and groups of population with similar needs and interests. This creates certain socioeconomic homogeneity among the commercial and residential inhabitants of UIs.
Thirdly, the reduced number of accesses to UIs creates funnel effects that cause particular pedestrian and motorised traffic dynamics. As a result, traffic concentrates in specific areas while others may have a calmer vibe.
Trivia
In the dystopian novel High-Rise, JG Ballard depicts the fall into chaos of a self-containing community in a luxury skyscraper. Placed somewhere in Northern London, High-Rise was published in 1975 when modernist architecture, with its high concrete towers, was at its peak. This architectural style has been widely criticised for creating isolated islands surrounded by green areas: “towers in the park”.
History
Some of the most significant cities in the world sprung along naturally protected areas. For instances, Paris was founded in the Île de la Cité, an island surrounded by the protection of the Seine. Nevertheless, this wasn’t enough to avoid the city being plundered by Vikings in the 9th century. Today’s Mexico City also expanded from an island on the disappeared lake Texcoco. The Aztec capital Tenochtitlan is said to have awed the Spanish conquerors. Other cities such as Amsterdam or Venice have also profited from the advantageous protection granted by water bodies.
On the contrary, London was founded by the Romans on the last bridgeable point over the Thames. Hard barriers and their points of passage have historically been places of trade and business. The original Roman settlement that London originated from, Londinium, is still pretty much readable in the layout of the streets the City. London’s current financial core remains a UI only accessible through specific points linked to the ancient walls’ gates: Aldgate, Bishops Gate, New Gate…
Human-made and natural hard boundaries have shaped Londoners’ settlement patterns and economic activities. In the late 16th century, the Huguenots, French protestant refugees, were offered asylum and allowed to settle in London. However, the city guilds held a monopoly over crafts and banking activities within one mile of the City. This forced the Huguenots to settle in Spitalfields and the surrounding areas. Although the Huguenots dispersed and were pretty much assimilated into broader London communities by the 19th century, the eastern London areas they inhabited became a place for newcomers to work and settle.
Redevelopments in East London have turned some of the most characteristic hard boundaries into an aesthetic asset. Canary Wharf has successfully integrated the former West India Company docks and shipyards into their built fabric. The docks have become part of their identity and act as the visible enactment of their special economic status. However, UIs are not only literal islands of skyscrapers and financial centres. Some areas, such as Crouch End or the Valley of Heath, have become close-knit communities in rural enclaves quite close to inner London. These historical areas, built in the 18th and 19th centuries, also have more contemporary counterparts still undergoing redevelopment- as is the case of the Leamouth Peninsula.