1 Within a geographical area, a concentration of economic activity brought about by, among others, external economies (such as a pool of skilled labour), economies of scale, cumulative causation, local authority planning, and chance. ‘The agglomeration of economic activities is a phenomenon as old as cities themselves’ (E. Soja2000). Phelps and Ozawa (2003) PHG27, 5 distinguish between proto-industrial, industrial, and post-industrial agglomerations, with no common, formative processes underlying each. Pflüger and Südekum (2008) J. Econ. Geog. 8, 1 believe that agglomeration processes depend on specific technical properties; Roos (2005) J. Econ. Geog. 5, 5 claims that the influence of geography on agglomerations is small: ‘at most, ∼36% of the total variation can be explained by the effects of geography’. Fan and Scott (2003) Econ. Geog. 79, 3 find a strong positive relationship between spatial agglomeration and productivity in China. See Feldman in G. Clark et al., eds. (2000).
2 In meteorology, the process by which cloud droplets grow by assimilating other droplets.