Urban

The kernels of older European cities, which have not been extensively rebuilt, tend to have city centers where the streets are jumbled together, often seemingly without a structural plan. This is a legacy of earlier unplanned or organic development. Today this is usually perceived by tourists to be quaint and picturesque.

Modern city planning has seen many different schemes for how a city should look. The most commonly seen pattern is the grid, almost a rule in the United States, and used for hundreds of years in China. Other forms may include a radial structure in which main roads converge on a central point, often the effect of of successive growth over long time with concentric traces of town walls and citadels - recently supplemented by ring-roads that take traffic around the edge of a town.

History of cities in general

Towns and cities have a long history, although opinions vary on whether any particular ancient settlement can be considered to be a city. The first true towns are sometimes considered to be large settlements where the inhabitants were no longer simply farmers of the surrounding area, but began to take on specialised occupations, and whereto trade, food storage and power was centralized.

By this definition, the first towns we know of were located in Mesopotamia, such as Ur, and along the Nile, the Indus Valley Civilisation and China. Before this time it was rare for settlements to reach significant size, although there were exceptions such as Jericho, Çatalhöyük and Mehrgarh.

The growth of ancient and medieval empires led to ever greater capital cities and seats of provincial administration, with Rome, its eastern successor Constantinople and successive Chinese and later Indian capitals approaching or exceeding the half-million population level. Similar large administrative and ceremonial centres emerged in other areas, though on a smaller scale.

During the European Middle Ages, a town was as much a political entity as a collection of houses. City residence brought freedom from customary rural obligations to lord and community: "Stadtluft macht frei" ("City air makes you free") was a saying in Germany. In Continental Europe cities with a legislature of their own wasn't unheard of, the laws for towns as a rule other than for the countryside, the lord of a town often being another than for surrounding land. In the Holy Roman Empire (i.e. medieval Germany and Italy) some cities had no other lord than the emperor.

In exceptional cases like Venice, Genoa or Lübeck, cities themselves became powerful states, sometimes taking surrounding areas under their control or establishing extensive maritime empires, though this could sometimes impede the later development of a wider national state and economy. Similar phenomena existed elsewhere, as in the case of Sakai, which enjoyed a considerable autonomy in late medieval Japan.

Most towns remained far smaller places, so that in 1500 only some two dozen places in the world contained more than 100,000 inhabitants: as late as 1700 there were fewer than fifty, a figure which would rise thereafter to 300 in 1900. A small city of the early modern period might contain as few as 10,000 inhabitants, a town far fewer still.

While the city-states of the Mediterranean and Baltic Sea languished from the 16th century, Europe's larger capitals benefited from the growth of commerce following the emergence of an Atlantic economy fuelled by the silver of Peru. By the 18th century, London and Paris rivalled the more traditional imperial capitals of Beijing, Istanbul and Tokyo.

Traditional approach

Three characteristics have been identified as defining a city: the number of people to area (density), the networks of the city, as well as a particular way of life. None of these characteristics alone is enough to make a place a city.

One important aspect of spatial thinking is looking at the connections of a city. Such connections allow to explain the unique character of a place. Rather than treating all cities the same, places are seen as interconnected through networks of culture, economics, trade or history. So while London and Tokyo are economically linked through stock markets, Graz and Stockholm are so by the cultural links of Cultural Capital of Europe.

These networks overlap and are concentrated in cities. Arguably this concentration of networks creates a unique feeling of a place. Such networks, however, do not only link cities with cities, but also a city to its surroundings. The notion of a city footprint reflect the idea that a city on its own is not sustainable: it depends on produce from its surroundings, it needs trade links and other connections for economic viability. Looking at networks, it becomes possible to explain the rise and fall of cities. This has to do with the changing importance of connections and is maybe best illustrated with the arrival of Spanish colonizers in America. Within a short time, connections to Madrid became more important than connections to the former centre Tenochtitlán.

The concentration of networks in cities can be used as an explanation of urbanization. It is the access to certain networks that attracts people. As various networks spatially run together in a confined area, people gather in cities. At the same time, this concentration of people means the introduction of new networks, such as social links, increasing the creation of new possibilities within cities. Urban social movements are a direct result of this possibility of mmaking new connections. It is this openness to new connections that makes cities both attractive and to a certain degree unpredictable.

Another important aspect of modern urban thinking is looking at the divisions within a city. This internal differentiation is linked to the external connections of a city. As places of meeting histories, cities are hybrid and heterogeneous. Hybrid they are as the connections which link places are bilateral, involving giving and taking in both directions. Heterogeneous they are because of the dynamism of cities. New encounters are ongoing processes where social relations and differences are constantly negotiated and shaped, reflecting the unequal power involved.

Neither the internal differentiations nor the connections and networks of a place on their own define a city. Internal divisions are caused by external links, while at the same time connections to the outside open up the possibility of new social divisions. Divisions and connections in every city are intertwined, and only by considering both aspects of spatial thinking the complexity of cities is approachable. Immigration illustrates this interconnection of external networks and internal divisions well. The networks concentrated in the core of the city attract immigrants. As they immigrate, the newcomers bring along their histories, bringing new networks or enforcing existing ones. At the same time, their history offers opportunities to identify with or likewise exclude. Division and connection come hand in hand. Rather than attempting to eradicate such tensions and contradictions in the theoretical framework, modern urban thinking – influenced by poststructuralist thought – accounts for both sides. Static universal bodies are replaced by multidimensional networks, allowing for fluidity and dynamism.

The notion of global cities regards the power of cities as contained within cities. The city is seen as a container where skills and resources are concentrated. The more successful city is able to concentrate more of these skills and resources. This makes the city itself more powerful in terms that it can influence what is happening around the world. Following this view of cities, it is possible to rank the world's cities hierarchically, as Friedmann and Wolff did in 1982.

Critics of the notion point out to the different realms of power. The term global city narrowly focuses on economics. Cities like Rome are powerful in religious terms. Additionally, it has been questioned whether the city itself can be regarded as an actor.

In 1995 Kanter argued that successful cities can be identified by three elements. To be successful, a city needs to be good thinkers (concepts), good makers (competence) or goode traders (connections). The interplay of these three elements, Kanter argued, means that good cities are not planned but managed.

Garbage and sewage are two major problems for cities, as is air pollution coming from internal combustion engines (see public transport). The impact of cities on places elsewhere, be it hinterlands or places far away, is considered in the notion of city footprinting (ecological footprint).

• Municipal government
• List of cities by country
• List of metropolitan areas by population
• Megacity
• Self-proclaimed Capitals of the World
• Cities of Japan

External links

Successful urban planning considers character, of "home" and "sense of place", local identity, respect for natural, artistic and historic heritage, an understanding of the "urban grain" or "townscape," pedestrians and other modes of traffic, utilities and natural hazards, such as flood zones.

Some say that the medieval piazza and arcade are the most widely appreciated elements of successful urban design, as demonstrated by the Italian cities of Siena and Bologna.

While it is rare that cities are planned from scratch (and, in case, with some risk of unsuccessful examples like for Brasilia), planners are important in managing the growth of cities, applying tools like zoning to manage the uses of land, and growth management to manage the pace of development. When examined historically, many of the cities now thought to be most beautiful are the result of dense, long lasting systems of prohibitions and guidance about building sizes, uses and features. These allowed substantial freedoms, yet enforce styles, safety, and often materials in practical ways. Many conventional planning techniques are being repackaged as smart growth.

There are some cities that have been planned from conception, and while the plans often don't turn out quite as planned, evidence of the initial plan often remains. See List of planned cities. Some of the most successful planned cities consist of cells that include park-space, commerce and housing, and then repeat the cell. Usually cells are separated by streets. Often each cell has unique monuments and gardening in the park, and unique gates or boundary-markers for the edges of the cell. The commercial areas naturally become diverse. These differences help instill a sense of place, while the similarities of the cells make each place in the city familiar.

Many urban areas show little sign of ever having being planned in any coherent or socially-aware way. Buildings and spaces may reflect the different priorities of a different era, or simply demonstrate an undue (anti-social or environmentally-insensitive) emphasis on the priorities of the organisation or individual that paid for their construction. Left-over parts of a town or city that appear to serve no particular purpose have been labelled by the pejorative acronym "SLOAP" meaning Space Left Over After Planning. Unfortunately such spaces are all too common, particularly in suburban areas, and planners, businesses, politicians, land agents and communities all have a duty to consider how these flaws in the urban fabric might be repaired.

Extreme weather, flood, war or other emergencies can often be greatly mitigated with secure evacuation routes and emergency operations centers. These are so inexpensive and unintrusive that they're a reasonable precaution for any urban space.

Many cities also have planned, built safety features, such as levees, retaining walls, and shelters.

Some planning methods might help an elite control ordinary citizens. This was certainly the case of Rome (Italy), where Fascism in the 1930s created ex novo many new suburbs in order to concentrate criminals and poorer classes away from the elegant town. France currently uses similar methods to control ethnic-arabic groups on welfare.

In recent years, practitioners have also been expected to maximise the accessibility of an area to people with different abilities, practising the notion of "inclusive design," to anticipate criminal behaviour and consequently to "design-out crime" and to consider "traffic calming" or "pedestrianisation" as ways of making urban life more bearable.

City planning tries to control criminality with structures designed from theories like socio-architecture or environmental determinism. These theories say that an urban environment can influence individuals' obedience to social rules. The theories often say that pschological pressure develops in more densely developed, unadorned areas. This stress causes some crimes and some use of illegal drugs. The antidote is usually more individual space and better, more beautiful design in place of functionalism.

Good planning attempts to place high densities near high-volume transportation. For example some cities permit commerce and multistory apartment buildings only within one block of train stations and four-lane boulevards, and require single-family dwellings and parks to be farther-away.

Densities are usually measured as the floor area of buildings divided by the land area. Ratios below 1.5 are low density. Ratios above five are very high density. Most exurbs are below two, while most city centers are well above five. Walk-up apartments with basement garages can easily achieve a density of three. Skyscrapers easily achieve densities of thirty or more. Higher densities tempt developers with higher profits. Cities try to lower densities to reduce infrastructure costs.

Automobiles are well suited to serve densities as high as 1.5 with basic limited-access highways. Innovations such as car-pool lanes and ruch-hour use taxes may get automobiles to densities as high as 2.5.

Densities above 5 are well-served by trains. Most such areas were actually developed in response to trains in the middle 1800s, and have large historical riderships that have never used automobiles.

The problem is that there is a no-mans-land of densities between about two and five that causes severe traffic jams of automobiles, yet are too low to be served by trains or light rail. The conventional solution is to use busses, but these and light rail systems normally fail when automobiles are available, achieving less than 1% ridership. Some theoretricians speculate that personal rapid transit might coax people from their automobiles, and yet effectively serve intermediate densities, but this has not been demonstrated. The Lewis-Mogridge Position claims that increasing road space is not an effective way of relieving traffic jams.

A strong belief that the behaviour of individuals living in or frequenting an area can be heavily influenced by its physical design and layout is called environmental determinism.

• List of urban planners
• Thomas Adams
• Jane Jacobs
• New Towns
• New urbanism
• Unitary urbanism

External Links