The public realm of cities and urban design

Almost all definitions of urban design state that it has something to do with the public realm (or the public domain or with public space) and the elements that define it. One of the best is:

Urban design draws together the many strands of place-making, environmental responsibility, social equity and economic viability; for example – into the creation of places of beauty and identity. Urban design is derived from but transcends related matters such as planning and transportation policy, architectural design, development economics, landscape and engineering. It draws these and other strands together.
 In summary, urban design is about creating a vision for an area and the deploying of the skills and resources to realise that vision (Llewellyn-Davies, 2000: 12).
The last sentence is particularly important. Here is another statement: 
Urban design should be taken to mean the relationship between different buildings; the relationship between buildings and streets, squares, parks and waterways and other spaces which make up the public domain . . . and the patterns of movement and activity which are thereby established; in short, the complex relationships
between the elements of built and unbuilt space.
Urban design consists of multi-building projects that vary in size from building complexes to precincts of cities to whole cities. Sometimes urban design includes the design of the buildings themselves, but often it impinges on the architecture of buildings only to the extent that their uses and façades, particularly on the
ground floor, define the public domain. But what then is the public domain?
Human organizations consist of public and private components. The distinction is not always clear because there are also semi-public and semi-private behaviours and places. In addition, what is considered to be private and what is considered to be public varies from culture to culture and within cultures over time (Madanipour, 2003). 
For professionals involved in any of the environmental design fields the public realm is comprised of two parts. The first deals with the public components of the physical environment (artificial and natural) in which behaviour occurs and the second specifies how communal decisions are made by governments and in the marketplace as defined by a country’s constitution (or in the case of the United Kingdom by precedent).
The first affects perceptions of the elements of urban design and the second, the process of urban designing.


Jon Lang 
book urban design