日本Mw9.0强震的高频GPS形变波特征初探

利用高频GPS数据长基线双差精密定位技术,获取2011年3月日本Mw9.0强震近场和远场GPS连续参考站的瞬时动态形变。分析表明：距震源较近的IGS站（USUD）的同震动态形变水平方向幅度超过60 cm,震后水平形变达到30 cm;位于远场的GPS连续参考站（JLYJ）的动态形变,清晰地给出了地震面波引起的地表形变波形。对JLYJ站的谱分析表明,地震面波引起的动态形变周期为10～17 s,并出现了两次峰值,东西向和垂向上的动态位移量远大于北南向,说明JLYJ站的形变主要由Rayleigh波及其谐波所主导,Rayleigh波的传播速度为3.5 km/s,波长约50 km。     

Correlation between grain shape and critical state characteristics of uniformly graded sands: A 3D DEM study

Acta Geotechnica - The multi-scale characteristics of particle morphology, including the overall form, local roundness and surface roughness, affect the critical state behavior of sands and should...     

A comparative study of the segmentation of weighted aggregation and multiresolution segmentation

Multiresolution segmentation (MRS) algorithm has been widely used to handle very-high-resolution (VHR) remote sensing images in the past decades. Unfortunately, segmentation quality is limited by the dependency of parameter selection on users’ experience and diverse images. Contrarily, the segmentation by weighted aggregation (SWA) can partly overcome the above limitations and produce an optimal segmentation for maximizing the homogeneity within segments and the heterogeneity across segments. However, SWA is solely tested and justified with digital photos in computer vision field instead of VHR images. This study aims at evaluating SWA performance on VHR imagery. First, multiscale spectral, shape, and texture features are defined to measure homogeneity of image objects for segmentation. Second, SWA is implemented to handle QuickBird, unmanned aerial vehicle (UAV), and GF-1 VHR images and further compared with MRS in eCognition software to demonstrate the applicability of SWA to diverse images in building, vegetation and water, forest stands, farmland, and mountain areas. Third, the results are fully evaluated with quantitative measurements on segmented objects and classification-based accuracy assessment on geographic information system vector data. The results indicate that SWA can produce higher quality segmentations, need fewer parameters and manual interventions, create fewer segmentation levels, incorporate more features, and obtain larger classification accuracy than MRS.     

LEO Enhanced Global Navigation Satellite System (LeGNSS):progress,opportunities, and challenges

With the completion of Chinese BeiDou Navigation Satellite System (BDS), the world has begun to enjoy the Positioning, Navigation, and Timing (PNT) services of ...     

遥感图像蚁群算法和加权图像到类距离检索法

遥感图像检索目的是从遥感图像库中寻找出与查询图像相关的图像,但在检索过程中一般只考虑查询图像与待检索图像的相似度,通常忽略了遥感图像库中图像之间的语义相似度.针对该问题,本文提出一种基于蚁群算法和改进的加权图像到类距离的遥感图像检索算法.首先利用信息素浓度描述遥感图像库中图像之间的语义相似度,然后采用蚁群算法更新信息素...     

A disaggregation approach for estimating high spatial resolution broadband emissivity for bare soils from Landsat surface reflectance

High spatial resolution land surface broadband emissivity (BBE) is not only useful for surface energy balance studies at local scales, but also can bridge the gap between existing coarser resolution BBE products and point-based field measurements. This study proposes a disaggregation approach that utilizes the established BBE–reflectance relationship for estimating high spatial resolution BBE for bare soils from Landsat surface reflectance data. The disaggregated BBE is compared to the BBE calculated from spatial–temporal matched Advanced Spaceborne Thermal Emission and Reflectance Radiometer emissivity product. Comparison results show that better agreement is achieved over relative homogeneous areas, but deteriorated over heterogeneous and cloud-contaminated areas. In addition, field-measured emissivity data over large homogeneous desert were also used to validate the disaggregated BBE, and the bias is 0.005. The comparison and validation results indicated that the disaggregation approach can obtain high spatial resolution BBE with better accuracy for homogeneous area.     

The paleogeographic implications of loess mounds: Laizhou Bay plain

Loess mounds are made of gray-yellow loess materials and the number is over 200 in the area of over 1000 km2 on the alluvial or marine-built plains south of Laizhou Bay (Figure 1). 1 The formal and distributional characteristics of loess mounds 1.1 Formal characteristics The plane forms of loess mounds are irregular oval or round. Their major axes are in north-south trending, most of them are 300 to 500 m long, with smaller ones tens m long, and individual larger ones more than 1,000 m …     

基础测绘E00数据的质量控制

随着江苏省基础测绘工作的深入开展，江苏省基础地理信息数据库的建立，为数据库提供高质量的空间数据迫在眉捷，本文介绍了运用EPSCAN2000软件采集数据后，在ARC／INFO和ARCVIEW中进行入库数据检查、处理，获取符合入库要求的E00数据的方法与过程。     

江苏省1∶25万、1∶100万基础数据修测与建库

1∶25万、1∶100万基础数据是江苏省地理空间信息基础框架的重要组成部分,本文根据江苏省地理空间信息基础框架的要求,结合全省现有的基础地理数据库建设的现状,叙述了对全省范围内的17幅1∶25万DLG、DOM,4幅1∶100万DLG数据如何进行修测、更新和入库,并建立相应的元数据库的过程和方法。     

遥感技术在攀枝花地区土壤侵蚀调查中的应用研究

利用彩红外航片与TM数据,分析提取土壤侵蚀的主要影响因子,采用层次分析法建立了研究区专家权重模型,确定出土壤侵蚀强度级别,继而分析了攀枝花地段的土壤侵蚀特征并提出了治理措施。