The Use of Remote Sensing in the Monitoring and Evaluation of Urban Sprawl in the Pearl River Delta: A Case Study of Dongguan

Abstract

The current fast economic growth is accompanied with rapid urban expansion and great loss of agricultural land in the Pearl River Delta. The lack of information and technology hinders planners and local officers to achieve sustainable development. This paper tries to demonstrate the potential of the integration of remote sensing and GIS for monitoring and analysing of land development in the Pearl River Delta. It is found that wasteful use of land resource exists with ‘blind’ development patterns. The fast diffusion of urban areas has caused loss of large amount of agricultural land. Based on GIS analysis, some protection measures can be formulated to curb the tendency of swallowing agricultural land for urban development. The area of urban use rapidly increased from 16 234.6 ha to 41 087.9 ha. in 19881993 in the study area, Dongguan. This means that 10.4% of the total land area was converted to urban use just within this short period. Moreover, most of the conversion only occurred in 19901993. It is found that the land loss in Dongguan in 19881993 mainly took place within a few kilometers nearby urban (town) centres or roads. Actually, 90 percent of the total land loss occurred within an average distance of 1.38 km from roads and 5.63 km from urban (town) centres. The result is not very surprising given that the proximity is a very important factor for land development. It is very clear that the city proper is under a quick expansion of its urban areas in recent years. A transition period with more land loss occurring in a further distance exists because of the diffusion process. It is interesting to see that there is a strong contrast between the diffusion in 19881990 and that in 19901993. The diffusion of the urban areas was limited in 19881990 while the diffusion was astonishingly strong in 19901993. It is because a large amount of agricultural land has been encroached for the development of real estate since 1992. However, the diffusion pattern is not identical as there is obvious variation for each town.

伴隨著經濟的快速增長，珠江三角洲近年來出現了迅速的城市化以及鄉村城市化的過程。沿著城鎮邊緣和公路兩旁，大片的農田被侵占來單方面地滿足城市開發的需要，忽略了糧食產量減少以及環境質量惡化等問題。利用遙感可以有效地監測珠江三角洲的城市擴張過程。在遙感多時相監測的基礎上通過熵的計算，可以定量地描述城市擴張的空間規律及擴散過程。