Quantifying the main urban area expansion of Guangzhou using Landsat imagery

This article takes the main urban area of Guangzhou as the study area. Twelve land-use maps were interpreted from Landsat Thematic Mapper images using feature enhancement technology and Naive Bayes-based weight vector AdaBoost (WV AdaBoost). The study shows that since 1987, with heavily cultivated land being lost and vegetation cover shrinking, the urban area has doubled in size. The effects of human activities on the landscape have become increasingly apparent and complicated. It also finds that the expansion pattern has been transformed from one in which the city's main urban area engulfed the surrounding residential area to one in which surrounding towns expanded, driven by the development of the main urban area. By analysing the relationship between the social economy, population, and land-use change, we show that the forces driving expansion of the urban area have differed in different periods. The principal driving forces are national policymaking and adjustment, the aggregation and diffusion of population and economic development. Multitemporal land-use maps allow long-term dynamic monitoring of urban land cover in Guangzhou and provide important details of urban expansion and changes in land use. We employed intervals of 2 and 3 years, and our results provide good supporting data for studies of urban extension trends and reasonable urban planning.