Application of random sets to model uncertainties of natural entities extracted from remote sensing images   总被引：1，自引：1，他引：0  

Xi Zhao  Alfred Stein  Xiaoling Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(5):713-723

Remotely sensed images as a major data source to observe the earth, have been extensively integrated into spatial-temporal analysis in environmental research. Information on spatial distribution and spatial-temporal dynamic of natural entities recorded by series of images, however, usually bears various kinds of uncertainties. To deepen our insight into the uncertainties that are inherent in these observations of natural phenomena from images, a general data modeling methodology is developed to embrace different kinds of uncertainties. The aim of this paper is to propose a random set method for uncertainty modeling of spatial objects extracted from images in environmental study. Basic concepts of random set theory are introduced and primary random spatial data types are defined based on them. The method has been applied to dynamic wetland monitoring in the Poyang Lake national nature reserve in China. Four Landsat images have been used to monitor grassland and vegetation patches. Their broad gradual boundaries are represented by random sets, and their statistical mean and median are estimated. Random sets are well suited to estimate these boundaries. We conclude that our method based on random set theory has a potential to serve as a general framework in uncertainty modeling and is applicable in a spatial environmental analysis.  相似文献   

中山港建设管理信息系统的设计研究   总被引：1，自引：0，他引：1  

刘凯澎  王润伟  樊妙  李晓英 《地理空间信息》2006,4(3):25-27

结合中山港建设管理信息系统的研发实践,介绍了系统的体系结构、网络架构,阐述了若干关键性技术问题及其解决方案,为探索小区信息化建设管理信息系统提供了有效途径。  相似文献   

机载激光点云数据中电力线自动提取方法     

陈驰  麦晓明  宋爽  彭向阳  徐文学  王珂 《武汉大学学报(信息科学版)》2015,40(12):1600-1605

提出了一种从机载激光点云数据中自动提取电力线的方法。首先利用顾及地形起伏特征的机载激光点云自动滤波方法移除地面点,利用维数特征以及方向特征自非地面点中分割获得电力线激光点云;然后对获取的电力线点采用二维霍夫变换和最小二乘拟合的方法求取每条电力线的中心线方程,根据中心线方程求取每条电力线上的激光点完成单电力线目标提取,并考虑了电力线在水平投影面内重叠时的情况;最后根据分块质心解算方法生成每条电力线上的三维节点,输出电力线矢量。采用实际线路巡检实验采集的机载激光点云数据进行实验,实验结果表明,该方法能从机载激光点云数据中提取出完整的电力线,并具有较好的鲁棒性,对电力巡线具有一定的实际意义。  相似文献   

网格高性能PGIS的研究与开发     

杨明  朱家松  张雅珉 《地理空间信息》2010,8(4):54-56

介绍参与式地理信息系统(PGIS)技术概念,简要分析PGIS在(C/S)网络结构下的一些核心问题。提出应用高性能计算与网格技术改进现有PGIS的思想,并以一个不同地点、同时间的地理协作案例,设计实现了一种基于网格的高性能PGIS以引导实施交通紧急疏散系统。  相似文献   

Centimeter-level precise orbit determination for the HY-2A satellite using DORIS and SLR tracking data     

Qiaoli Kong  Jinyun Guo  Yu Sun  Chunmei Zhao  Chuanfa Chen 《Acta Geophysica》2017,65(1):1-12

The HY-2A satellite is the first ocean dynamic environment monitoring satellite of China. Centimeter-level radial accuracy is a fundamental requirement for its scientific research and applications. To achieve this goal, we designed the strategies of precise orbit determination (POD) in detail. To achieve the relative optimal orbit for HY-2A, we carried out POD using DORIS-only, SLR-only, and DORIS + SLR tracking data, respectively. POD tests demonstrated that the consistency level of DORIS-only and SLR-only orbits with respect to the CNES orbits were about 1.81 cm and 3.34 cm in radial direction in the dynamic sense, respectively. We designed 6 cases of different weight combinations for DORIS and SLR data, and found that the optimal relative weight group was 0.2 mm/s for DORIS and 15.0 cm for SLR, and RMS of orbit differences with respect to the CNES orbits in radial direction and three-dimensional (3D) were 1.37 cm and 5.87 cm, respectively. These tests indicated that the relative radial and 3D accuracies computed using DORIS + SLR data with the optimal relative weight set were obviously higher than those computed using DORIS-only and SLR-only data, and satisfied the requirement of designed precision. The POD for HY-2A will provide the invaluable experience for the following HY-2B, HY-2C, and HY-2D satellites.  相似文献   

Integration of Range Split Spectrum Interferometry and conventional InSAR to monitor large gradient surface displacements     

《International Journal of Applied Earth Observation and Geoinformation》2019

Incorrect unwrapping of dense interferometric fringes caused by large gradient displacements make it difficult to measure mining subsidence using conventional Interferometric Synthetic Aperture Radar (InSAR). This paper presents a Range Split Spectrum Interferometry assisted Phase Unwrapping (R-SSIaPU) method for the first time. The R-SSIaPU method takes advantage of (i) the capability of Range Split Spectrum Interferometry of measuring surface displacements with large spatial gradients, and (ii) the capability of conventional InSAR of being sensitive to surface displacements with limited spatial gradients. Both simulated and real experiments show that the R-SSIaPU method can monitor large gradient mining-induced surface movements with high precision. In the case of the Tangjiahui mine, the R-SSIaPU method agreed with GPS with differences of approximately 4.2 cm, whilst conventional InSAR deviated from GPS with differences of nearly 1 m. The R-SSIaPU method makes phase unwrapping less challenge, especially in the cases with large surface displacements. In addition to mining subsidence, it is believed that the R-SSIaPU method can be used to monitor surface displacements caused by landslides, earthquakes, volcanic eruptions, and glacier movements.  相似文献   

结合地理国情普查和监测数据的交通网络发展空间格局监测研究     

胡传文  骆光飞  杨文敬  倪锡春 《测绘通报》2019,(2):131-136

交通通达指数是表征一个区域交通网络空间格局的重要指标。本研究立足于地理国情普查和监测中交通要素等相关数据成果,开展了基于交通网络密度和交通便捷度交通的通达指数测算相关研究,引入了一套核密度分析、欧氏距离分析、吸引力分析等交通通达指数计算方法,并以杭州市为试验区,开展交通网络空间格局监测。  相似文献   

Atmospheric correction of ocean color imagery over turbid coastal waters using active and passive remote sensing     

田礼乔  陈晓玲  张亭禄  龚威  陈莉琼  陆建忠  赵羲  张伟  于之锋 《中国海洋湖沼学报》2009,27(1):124-128

This paper demonstrates an atmospheric correction method to process MODIS/Aqua (Moderate-resolution Imaging Spectroradiometer) ocean color imagery over turbid coastal waters with the aid of concurrent CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) aerosol data, assuming that there exists "nonturbid" water in the study area where MODIS aerosol optical properties can be retrieved accurately. Aerosol properties from CALIOP measurements were obtained and related to those from MODIS. This relationship, combined with CALIOP aerosol data, was extended to turbid water to derive MODIS aerosol properties, where atmospheric correction using MODIS data alone often fails. By combining MODIS and CALIOP data, aerosol signals were separated from the total signals at the satellite level, and water-leaving radiances in turbid waters were subsequently derived. This method was tested on several MODIS/Aqua ocean color images over South China turbid waters. Comparison with field data shows that this method was effective in reducing the errors in the retrieved water-leaving radiance values to some extent. In the Zhujiang (Pearl) River Estuary, this method did not overestimate the aerosol effects as severely, and provided far fewer negative water-leaving radiance values than the NASA (National Aeronautics and Space Administration) default methods that used MODIS data alone.  相似文献   

DOC遥感研究进展——基于全球大河DOC与CDOM保守性特征     

潘德炉  刘琼  白雁 《海洋学报》2012,34(4):1-11

目前,溶解有机碳(DOC)遥感反演研究主要集中在河口及陆源影响较大的边缘海区,大多数是利用DOC与有色溶解有机物(CDOM)或DOC与盐度的经验关系获取。为了较好的理解DOC的遥感反演机理,收集了全球主要大河(流量排名前25中16条)及边缘海DOC与CDOM浓度与保守性分布状况,发现大多数河口CDOM呈现保守性分布,DOC呈现非保守性分布。基于DOC与CDOM保守性行为的主要影响因素分析以及研究海区的生物地球化学特征,论述了DOC遥感反演算法的研究进展,提出了DOC遥感反演需要考虑DOC受不同主要控制因素(如保守混合与生物作用等)的影响,并对这些控制因素进行量化。  相似文献   

Cloud removal for remotely sensed images by similar pixel replacement guided with a spatio-temporal MRF model     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

Cloud cover is generally present in remotely sensed images, which limits the potential of the images for ground information extraction. Therefore, removing the clouds and recovering the ground information for the cloud-contaminated images is often necessary in many applications. In this paper, an effective method based on similar pixel replacement is developed to solve this task. A missing pixel is filled using an appropriate similar pixel within the remaining region of the target image. A multitemporal image is used as the guidance to locate the similar pixels. A pixel-offset based spatio-temporal Markov random fields (MRF) global function is built to find the most suitable similar pixel. The proposed method was tested on MODIS and Landsat images and their land surface temperature products, and the experiments verify that the proposed method can achieve highly accurate results and is effective at dealing with the obvious atmospheric and seasonal differences between multitemporal images.  相似文献