Spatial-temporal Evolution and Driving Forces of Construction Land Expansion in Chengdu from 1980 to 2018

Based on land use grid data, the change characteristics and driving forces of urban construction land expansion in Chengdu from 1980−2018 were explored by means of urban expansion intensity and speed index, iso-fan analysis, land use transfer matrix and PLUS model. The results show that from 1980 − 2018, the area of construction land in Chengdu continued to increase, with a total increase of 1.38 × 10⁴ hm² in 38 years, mainly from the decrease of cultivated land area. The direction of construction land expansion is obvious, showing a trend of inclination to the southeast, and the eastern and southern regions continue to expand. The expansion intensity gradually decreased from the urban center to the peripheral districts and counties, and the expansion intensity was the highest in the central urban area. The fastest expanding regions are concentrated in the east and south of Shuangliu, Wuhou and Jianyang, and the slowest in the west of Pujiang, Qionglai and Chongzhou. Social and economic factors such as GDP and distance from government residence and natural factors such as elevation, annual average temperature and water area are the main driving factors affecting the expansion of urban construction land. Under the influence of natural factors such as water area, elevation and annual average temperature, and the promotion of social and economic factors such as GDP, distance from government residence and traffic conditions, the construction land area in Chengdu keeps expanding and has obvious direction.