利用MODIS产品和DMSP/OLS夜间灯光数据监测城市扩张

选用多时序MODIS数据产品和晚间灯光指数数据,采用CART数据挖掘方法和改进的Niblack 阈值分割技术,对2001-2010 年之间的浙江省城市扩张情况开展了动态监测。结果显示：在多时序数据信息挖掘的基础上,利用区域灯光指数局部阈值,可以有效地分割城镇和非城镇类型,从而提高城镇专题信息提取的精度;从2001 年到2010 年,浙江省城市扩张迅速,年平均扩张速度为297.35 km²/a,平均扩张速度以余杭、萧山和绍兴为中心,以宁波和瑞安为次中心递减;扩张强度最大的是衢县,其次是开化县和海宁市。以杭州为例分析城市扩张的空间特征,其城市空间紧凑度从0.38 上升到了0.48,空间结构趋于紧凑;城市中心向西北方向移动了约3km,揭示着其向西北方向扩展的主要趋势。

Monitoring urban expansion of Zhejiang Province using MODIS/EVI data products and DMSP/OLS nighttime light data

The multi-temporal MODIS/EVI data products and DMSP/OLS nighttime light index data are selected, and the CART data mining method and improved Niblack threshold segmentation technique are applied to monitor the urban expansion dynamically from 2001 to 2010. The result showed that: on the basis of multi-temporal data mining, with the local light index threshold, the comprehensive utilization of MODIS/EVI time-series data and DMSP/ OLS nighttime light index data can effectively identify the urban land cover and non-urban land cover. The urban land of Zhejiang Province has expanded rapidly from 2001 to 2010. In terms of the urban expansion rate, the average annual growth is about 297.35 km²/a. Yuhang, Xiaoshan and Shaoxing can be regarded as the principal axis; Ningbo and Rui''an can be the secondary centers, and the urban expansion rates of other districts around them are progressively decreasing. In terms of the expansion intensity, the largest value is observed in Quxian County, followed by Kaihua and Haining. In the case of Hangzhou, the spatial compactness increased from 0.38 to 0.48, which implies spatial structure of Hangzhou has become more compact, and the city center has moved around 3 km towards the northwest, which reveals that the main expansion trend is towards the northwest.