The Circle Differentiation of the Three-dimensional Architectural Forms in the Main Urban Area of Guangzhou and Its Influencing Factors

The circle differentiation of the main indicators of the three-dimensional shape of buildings in the main urban area and its influencing factors through concentric circles are analyzed on the basis of the single point buil-ding data of the main urban area of Guangzhou in 1960, 1990 and 2017 combined with land price and population density. The results show that the three-dimensional architectural form of the main urban area of Guangzhou is similar to a circle and the formation and evolution of the differentiation pattern depend on the joint action of the geographical pattern, urban planning and market forces of the plain-type city near mountains and waters. First, since 1960 the CBD center of the main urban area of Guangzhou has been moving eastward, but the building height, building density and building height dispersion index all decrease from the center of the main urban area to the su-rrounding area. The proportion of oblique buildings has increased outwards, and the circle differentiation is obvious. At the same time, the three indexes increase as a whole, and the increase rate of the core area was higher than that of the surrounding area. Second, the succession rate of the three-dimensional form increases from the core of Liwan and Yuexiu to the outer circle; based on the four indexes of land price, population density, building height and building density, the main urban area can be aggregated into the circle type which gradually changes from the old urban area to the outside on the grid scale of 1 000 m. Third, combined with land price index and population density, the circle pattern determines the three-dimensional shape of the circle differentiation; from the center of the main urban area to the north, the increase of the elevation leads to the increase of the proportion of oblique pattern in the architectural plane form.