Rank-Size, Expansion and Form Characteristics of Urban Built-Up Areas in Pearl River Delta during 1930s and 1960s

Based on the 1:50 000 Topography map of 1930s and 1960s and supported by GIS, the area, rank-size, compact ratio and circularity ratio of 15 built-up areas in the Pearl River Delta are calculated, and the growth intensity and form characteristics during 1930s and 1960s are analyzed. The rank-size distribution of 1930s and 1960s was Y=11.48X-1.30 and Y=15.63X-1.28 respectively. The structure of Urban system had the similar characteristics, presenting the'pyramid' structure. The built-up areas were small and the expansion speed was slow with 0.98km2/10a. The growth pattern was mainly the expansion along the principal axis or around the built-up area. The form compact nature was weak, going to the decentralization tendency. According to the urban development conditions and form characteristics, the urban forms were divided into three types-low hill leading type, river network leading type and plain leading type.