2013–2017年海南岛陆域水体遥感提取数据集

陆域水体分布是全球水资源安全和管理、气候变化研究、生态环境动态监测等不可或缺的重要基础信息。本文基于高分1号数据与Landsat 8 OLI数据,通过最小冗余最大相关性特征选择(mRMR)算法,采用面向对象知识规则集自动化提取海南岛2013–2017年连续5a的陆域水体分布信息,结合高空间分辨率遥感影像与Google Earth对分类结果进行精度验证,得到Kappa系数分别为84.67%,85.98%,80.61%,88.66%,90.66%,分类结果精度较高。本数据集可直接用于陆域地表水体时空分布研究,也可为水环境如水体水质研究、水资源安全评估等提供数据基础。

基于影像融合的冬小麦种植面积提取适宜尺度研究

为探究江苏省冬小麦种植面积遥感提取的田块适宜尺度,选取冬小麦拔节期空间分辨率为2 m×2 m的GF-1全色影像和30 m×30 m的HJ-1多光谱影像进行研究。首先,将GF-1全色影像进行8 m和16 m重采样,形成3种不同尺度全色影像,然后分别与HJ-1多光谱影像进行主成分变换法融合,生成空间分辨率分别为2 m×2 m、8 m×8 m和16 m×16 m的3种不同尺度多光谱影像,并通过融合影像质量评价以及光谱特征值和非监督分类的面积精度进行比较。结果表明,3种尺度融合影像均值差异不大,分别为81.20、79.26和79.44。3种尺度融合影像的平均梯度值和标准差差异明显,其中16 m×16 m融合影像显著高于2 m×2 m、8 m×8 m融合影像,融合影像质量较原始多光谱影像质量发生明显改善,突出了丰富的植被光谱信息。从3种融合影像冬小麦种植面积提取精度可以看出,16 m×16 m融合影像冬小麦种植面积的提取精度较理想,达到96.73%。研究结果说明,16 m×16 m空间分辨率遥感影像较为适合江苏省冬小麦种植的田块分布特征,有利于冬小麦种植面积遥感准确提取。

Spatial Structure and Land Use Control in Extended Metropolitan Region of Zhujiang River Delta,China

The Zhujiang (Pearl) River Delta is one of the most developed Extended Metropolitan Regions (EMR) in China.With the rapid urbanization,the agglomeration of population and industries has emerged,which has led to dramatic changes of spatial structure and land use in this region.With data of high resolution TM remote sensing images and Google Earth maps,this paper identified and analyzed the spatial pattern of the Zhujiang River Delta EMR using Envy and ArcGIS tools.It was found that 1) the industrial land uses were expanding substantially,particularly on the bank sides of the Zhujiang River estuary;2) large-scale housing developments were concentrated in the fringe of metropolitan areas such as those of Guangzhou and Shenzhen;3) a regional transportation network with the spatial pattern of ″1 circle +2 pieces + 3 axes″ had significantly affected the location choice of manufacture enterprises.At the same time,both highly specialized land use and severely mixed land use patterns were identified.As a consequence of the latter,land use efficiency of the whole EMR areas was reduced.Moreover,ecologic and environmental problems were severe.Based on the above analysis,suggestions were given from the viewpoint of spatial safety,land use efficiency,and the reorganization of spatial structure in the Zhujiang River Delta EMR.

Evaluation of Three-dimensional Urban Expansion: A Case Study of Yangzhou City, Jiangsu Province, China

With rapid urban development in China in the last two decades, the three-dimensional(3D) characteristic has been the main feature of urban morphology. However, the vast majority of researches of urban growth have focused on the planar area(two-dimensional(2D)) expansion. Few studies have been conducted from a 3D perspective. In this paper, the 3D urban expansion of the Yangzhou City, Jiangsu Province, China from 2003 to 2012 was evaluated based on Geographical Information System(GIS) tools and high-resolution remote sensing images. Four indices, namely weighted average height of buildings, volume of buildings, 3D expansion intensity and 3D fractal dimension are used to quantify the 3D urban expansion. The weighted average height of buildings and the volume of buildings are used to illustrate the temporal change of the 3D urban morphology, while the other two indices are used to calculate the expansion intensity and the fractal dimension of the 3D urban morphology. The results show that the spatial distribution of the high-rise buildings in Yangzhou has significantly spread and the utilization of the 3D space of Yangzhou has become more efficient and intensive. The methods proposed in this paper laid a foundation for a wide range of study of 3D urban morphology changes.

Landslides and Slope Fissures Triggered by the April 14,2010 Yushu Earthquake, China

On April 14, 2010 at 07：49 （Beijing time）, a catastrophic earthquake with Ms 7. 1 occurred at the central Qinghai-Tibetan Plateau. The epicenter was located at Yushu county, Qinghai Province, China. A total of 2036 landslides were determined from visual interpretation of aerial photographs and high resolution remote sensing images, and verified by selected field investigations. These landslides covered a total area of about 1. 194km~. Characteristics and failure mechanisms of these landslides are listed in this paper, including the fact that the spatial distribution of these landslides is controlled by co- seismic main surface fault ruptures. Most of the landslides were small scale, causing rather less hazards, and often occurring close to each other. The landslides were of various types, including mainly disrupted landslides and rock falls in shallows and also deep-seated landslides, liquefaction induced landslides, and compound landslides. In addition to strong ground shaking, which is the direct landslide triggering factor, geological, topographical, and human activity also have impact on the occurrence of earthquake triggered landslides. In this paper, five types of failure mechanisms related to the landslides are presented, namely, the excavated toes of slopes accompanied by strong ground shaking; surface water infiltration accompanied by strong ground shaking; co- seismic fault slipping accompanied by strong ground shaking; only strong ground shaking; and delayed occurrence of landslides due to snow melt or rainfall infiltration at sites where slopes were weakened by co-seismic ground shaking. Besides the main co-seismic surface ruptures, slope fissures were also delineated from visual interpretation of aerial photographs in high resolution. A total of 4814 slope fissures, with a total length up to 77. lkm, were finally mapped. These slope fissures are mainly distributed on the slopes located at the southeastern end of the main co-seismic surface rupture zone, an area subject to strong compression during the earthquake.

CHEOS Major Special Project Promotes Development of Chinese Commercial Remote Sensing Cameras

High resolution remote sensing data has been applied in many fields such as national security, economic construction and in the daily life of the general public around the world, creating a huge market. Commercial remote sensing cameras have been developed vigorously throughout the world over the last few decades, resulting in resolutions down to 0.31 m. In 2010, the Chinese government approved the implementation of the China High-resolution Earth Observation System(CHEOS) Major Special Project, giving priority to development of high resolution remote sensing satellites. More than half of CHEOS has been constructed to date and 5 satellites operate in orbit. These cameras have different characteristics. A number of innovative technologies have been adopted, which have led to camera performance increasing in leaps and bounds. The products and the production capability enables the remote sensing technical level to increase making it on a par with Europe and the US.