中文摘要：

文章提出了一种国土开发密度的三维综合评估方法,即从开发强度、开发紧凑度和开发程度3个维度对国土开发密度进行多尺度综合评估,将国土开发密度由二维空间向三维空间扩展。以珠江三角洲城市群为例,利用夜间灯光数据与Landsat TM等多源遥感影像数据,快速获取其区域建设用地及其上的社会经济要素空间分布信息,并采用三维综合评估方法对其的国土密度进行综合评价。结果表明：1）自1998年以来,珠江三角洲城市群国土开发模式以低密度蔓延式为主,新增建设用地开发程度低;伴随着建设用地规模的迅速扩张,国土开发紧凑度呈下降趋势。2）国土开发密度空间差异明显,集中体现为城市群内外圈层分异特征日趋显著,内圈层的开发强度和开发程度明显高于外圈层。3）各城镇开发强度与开发紧凑度之间整体呈现较为明显的＂U＂型曲线关系,开发强度与开发程度之间的也存在一定的正相关,即随着开发强度的提高,开发程度整体上呈上升趋势。与传统的国土开发密度评估方法相比,基于多源遥感数据的国土开发密度三维综合评估方法能够从规模、平面布局模式以及开发程度等多个维度综合反映国土开发模式的时空变化,并且能够在区域、城市、城镇、公里格网多个尺度开展研究,对于揭示国土开发模式的基本特征与时空变化具有重要意义。

英文摘要：

This paper was aimed at developing a three-dimensional approach to evaluate development density using multi-source remote sensing data. The three-dimensional evaluation model of development density is composed of development intensity, development compactness, and development level evaluation. Development intensity is the proportion of built-up areas. Development compactness describes the pattern（fragmented or centralized） of built-up areas. Development level describes the density of economic activities, population and building, and we used economic intensity as its proxy in this paper. We applied this three-dimensional evaluation model to the Pearl River Delta Megalopolis（PRDM）, which is one of the most rapidly developing regions in China, and found the following. 1） Rapid urban expansion with the decrease of development compactness was the leading feature of development in PRDM. From 1998 to 2012, the development intensity of the PRDM increased from 8.08% to 16.93%, and the economic intensity increased from 191 million Yuan/km2 to 594 million Yuan/km2, but the development compactness declined from 0.008 2 to 0.006 5, indicating that the spatial form of PRDM tended to be more fragmented. Among the nine cities in PRDM, Shenzhen was the only city whose development compactness increased. Despite PRDM saw a significant increase in economic intensity since 1998, most of the increase should be attributed to the promotion of high land use efficiency of the already existing construction land in 1998. 2） The regional differences in development density were very remarkable. Both evaluation results at town scale as well as 1-km spatial resolution showed that the gaps in development intensity and economic intensity between the inner and outer circles of PRDM were obvious and had been enlarging from 1998 to 2012. In the central area of PRDM, the development intensity exceeded 40% in 2012, while most fringe areas＇ development intensities were still less than 10%. The cities were different in economic intensity b