Flat versus volumetric methodologies: Restructuring spatial analysis and other indices

In cities of low or medium density, it is possible to conduct a configurative analysis using mobility networks as the main structural elements for the landscape (Bruyns, 2011; Read and Bruyns, 2007). Expressed as a ‘movement-function’ indicator at three distinct scales, the overall results diverge from conventional typological driven analysis, placing emphasis on movement patterns and how commercial functions cluster to each network. Not as a consequence of form but seen as an element that lends structure to the city, the ‘Flat City’ approach (Read, 2005) views mobility networks themselves as key structural indicators, based on three scales of mobility that highlight the social use of space, public as well as private. In contrast to the flat city, high density cities, or aptly named ‘Volumetric Cities’ (Shelton et al., 2010), are challenged by spatial compression that establish additional dependencies on mobility networks. Apart from the conventional use of movement networks to explicate form, ‘Volumetric Cities’ lays additional importance on pedestrian networks. Removed from the city surface, these networks are interwoven with both the ‘in’ and ‘exterior’ conditions of the city. As such, functions become interlaced at multiple stacked levels, which challenges conventional methods of spatial analysis and planning which rely on two-dimensional thinking. In this light, the applicability of the Flat City model remains questionable and as yet untested in the volumetric contexts. In Space Syntax, several attempts to analyse 3D environments have been tried (Dalton et al., 2015; Van Bilsen, 2009), however, they focus on smaller urban areas. For larger metropolitan areas, the “unlink” function is used to process urban areas with a complex street network operating on several floors (Hillier et al., 2009; Van Nes, 2009). As a challenge to existing methodology, this paper questions the applicability of the Flat City, network driven model, and its dependencies on specific scales of movement networks in the context of the high density landscape. First, the paper will outline the basic premise of previous empirical work, before highlighting the challenges in the reapplication of this approach in the urban context of Hong Kong. As part of its aims, the discussion wishes to illustrate new approaches to ‘vertical’ spatial analysis whilst concluding on the necessary methodological adjustments for the reapplication of this network method in high density urban landscapes.