Urban Formrefers to- the physical layout and- design of the city.- to the spatial imprint of an urban transport system- as well as the adjacent physical infrastructures.Jointly, they confer a level of spatial arrangement to cities.
Urban Form ‘urban form is definedas the spatial pattern of human activities at a certain point in time’.
URBAN STRUCTUREUrban (spatial) structure.Refers tothe set of relationships arising out of the- urban form-and its underlying interactions of-----people,-------freight and---------information.
URBAN STRUCTUREthe urban form and its spatial structure arearticulated by two structural elements:- Nodes.- Linkages.
URBAN STRUCTURENodes- These are reflected in the centrality of urban activities, - can be related to the spatial accumulation of economicactivities or to the accessibility to the transport system. - Terminals, such as ports, railyards, and airports, areimportant nodes around which activities agglomerate atthe local or regional level. - Nodes have a hierarchy related to their importance andcontribution to urban functions, such as production,management, retailing and distribution.
URBAN STRUCTURELinkages.-These are the infrastructures supporting flows from, toand between nodes.-The lowest level of linkages includes streets, which arethe defining elements of the urban spatial structure.-There is a hierarchy of linkages moving up to regionalroads and railways and international connections by airand maritime transport systems.
U Two basic forms of interdependent nodes are at the core of the urban spatial structure: Accessibility nodes. -Relate to locations that transfer passengers and freight, - include terminals such as ports, rail stations, airports and distribution centers. -Most cities owe their initial development to a location that grants access to local, regional and/or international circulation, commonly a port site. - Accessibility nodes are often dependent on the specific geographical requirements of each transport nodes, notably in terms of space consumption.
URBAN FORM AND SPATIAL STRUCTURENodes, Linkages and Urban Form Economic nodes. -Refer to locations that perform a function of economic significance. -These functions are extremely varied and can include transformation, administration, education, retailing and leisure. -Economic nodes tend to agglomerate, or to cluster, and are often dependent on access, if not close proximity, to an accessibility node or a linkage. -Such clusters often take the form of central business districts, commercial strips industrial districts or logistics zones.
URBAN FORM AND SPATIAL STRUCTURENodes, Linkages and Urban Form -The presence of nodes requires linkages, which can beserviced by different transport modes.-Road and transit linkages are obviously local in scopeoften taking the form of a grid that characterizes the formof many cities,-while rail, maritime and air linkages integrate the city to awider context of distribution and trade.-The complex set of relationships between nodes and theirlinkages imply an urban form which is unique in eachcase.
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a CityThe urban spatial structure basically considers- the location of different activities- as well as their relationships.
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a CityCore activities are those of the highest order in the urbanspatial structure, namely tertiary and quaternary activitiesinvolved in management (finance and insurance) andconsumption (retailing).Central activities are concerned by production anddistribution with activities such as warehousing,manufacturing, wholesaling and transportation.Peripheral activities are dominantly residential orservicing local needs.
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a CityA central area refers to an agglomeration of core and/orcentral activities within a specific location.The emergence of a CBD (Central Business District; thecentral area of a city) is the result of an historical process, - often occurring over several centuries (depending onthe age of a city),-that has changed the urban form and-the location of economic activities.each city has its own history, but it is possible toestablish a general common process:
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a City(A)Pre industrial era.For cities that existed before the industrial revolution, the CBD was limited to small section of the city generally nearby the waterfront, the market and/or a site of religious or political importance.These were locations where major transactions took place and thus required financial, insurance, warehousing and wholesale services.
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a City(B) Industrial revolution.With the industrial revolution came mass production andmass consumption. This permitted the emergence of adistinct retailing and wholesaling part of the CBD whilemanufacturing located outside the core.Managing these expanding activities also created anincreasing need for office space that located nearbytraditional places of financial interaction.As the industrial revolution matured, major transportationaxis spurred from the central area towards the periphery.
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a City(C) Contemporary era.After the Second World War, industries massivelyrelocated away from central areas to suburban areas,leaving room to the expansion of administrative andfinancial activities.The CBD was thus the object of an importantaccumulation of financial and administrative activities,particularly in the largest cities as several corporationsbecame multinational enterprises.
URBAN SPATIAL STRUCTURE Evolution of the Spatial Structure of a City(C) Contemporary era.These activities were even more willing to pay higherrents than retailing, thereby pushing some retail activitiesout of the CBD.New retailing sub-centers emerged in suburban areasbecause of road accessibility and because of the needs toservice these new areas.Warehousing and transportation, no longer core areaactivities, have also relocated to new peripheral locations.The spatial structure of many cities became increasinglymulti-nodal.