the gauteng spatial development framework - Gauteng Online

one level, the connectivity model is a tool for searching the urban system for diagnosticclues to the effectiveness or otherwise of the urban structure.More importantly, however, it is a tool for examining the likely effects of additionalinfrastructure aimed at increasing the urban integration of an area. For example, an areasuch as Soweto, despite its very large population, is poorly connected to the wider urbansystem for historical reasons, and much of Soweto's future achievement as an importantsector of the GCR (and Johannesburg more particularly) relies substantially on improvingits spatial integration with the wider system. The connectivity model assists therefore (a)in detecting the lack of connection and (b) testing what infrastructural improvements inthis regard would be most effective.Figure 3-8: The Morphological Model:The urban structure assignment zonesMODEL 3: THE CONNECTIVITY MODELThe Connectivity Model is indicative of the degree of spatial integration (or lack thereof)of the GCR as a whole such that one can discern those parts or elements of the GCR thatare well integrated (and therefore, presumably, showing relatively high levels of urbanachievement) and those parts that are relatively disconnected (and therefore, in manyinstances, likely to be showing high levels of marginalisation from the urban system). AtThe principle behind the Connectivity Model is that spatial elements (linear movementelements in this case) can be broken down into components, analysed as networks ofchoices, and represented as maps and graphs that describe the relative connectivity andintegration of those spaces and graphs that describe the relative connectivity and integrationof those spaces. Whilst there are a number of analysis methods of a street network, suchas Integration, Choice and Depth Distance, the main concern with the currentexercise is the measure of Integration and Depth:Integration measures how many turns one has to make from a street segment to reachall other street segments in the network, using shortest paths. The first intersecting segmentrequires only one turn, the second, two turns and so on. The street segments that requirethe least number of turns to reach all other streets are called 'most integrated' and areusually represented with hotter colours, such as red or yellow.Depth in the context of the Connectivity Model is a process that measures the lineardistance from the centre point of each street segment to the centre points of all the othersegments. If every segment is successively chosen as a starting point, a graph of accumulativefinal values is achieved. The streets with lowest Depth Distance values are said to be nearestto all the other streets.The results of this Connectivity Model provide a spatial representation that shows areasthat are well integrated, and thus more accessible, and areas that are more segregated,SECTION 3: THE MODELLING ELEMENTS OF THE GSDFGAUTENG SPATIAL DEVELOPMENT FRAMEWORK 2011GAUTENG GROWTH AND DEVELOPMENT AGENCY44