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Validation methods of LAI products on the basis of scaling effect

遥感学报 2015年第1期19卷 134-142页

作者： LIAO Yanran GAI Yingying YAO Yanjuan FAN Wenjie XU Xiru YAN Binyan Institute of Remote Sensing and gis Peking University Beijing 100871 China Beijing Key Laboratory of Spatial Information Integration & Its applications Beijing 100871 China Institute of Oceanographic Instrumentation Shandong Academy of Sciences Qingdao 266001 China Satellite Environment Center Ministry of Environmental Protection Beijing 100094 China Jackson School of Geosciences the University of Texas at Austin Austin 78712 USA

Validation is one of the most important processes used to evaluate whether remotely sensed products can accurately reflect land surface configuration. Leaf Area Index( LAI) is a key parameter that represents vegetation canopy structures and growth conditions. Accurate evaluation of LAI products is the basis for applying them to land surface models. In this study,validation methods of coarse resolution MODIS and GLASS LAI products for heterogeneous pixels are established on the basis of the scaling effect and the scaling transformation. Considering spatial heterogeneity and growth difference,we transformed LAI from field measurements into a 1 km resolution scale with the aid of middle resolution images. We used average LAI and apparent LAI separately to validate the algorithms and products of MODIS and GLASS LAI. Two study areas,Hebi City and the Yingke Oasis,were selected for validation. Both MODIS and GLASS LAI products underestimate the true LAI in crop area. However,this result cannot be completely attributed to their algorithms. Instead,the primary reason is the heterogeneity and nonuniformity of the coarse *** is evident in the Yingke Oasis,where heterogeneity is significant. Given that GLASS LAI product is the fusion of multiple LAI products,the mean value of this product is closer to the real situation,but the dynamic range is narrower than that of MODIS LAI product.

关键词： validation leaf area index scaling effect scaling transformation

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Assessment of soil erosion and sediment delivery ratio using remote sensing and gis:a case study of upstream Chaobaihe River catchment, north China

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International Journal of Sediment Research 2008年第2期23卷 167-173页

作者： Weifeng ZHOU1 and Bingfang WU2 1 Doctor candidate,Graduate School of the Chinese Academy of Sciences(CAS),Beijing 100039,China 2 Prof.,Institute of Remote Sensing applications,Chinese Academy of Sciences(CAS),Beijing 100101,China Doctor candidate Graduate School of the Chinese Academy of Sciences(CAS) Beijing 100039 China Prof. Institute of Remote Sensing Applications Chinese Academy of Sciences(CAS) Beijing 100101 China

Soil erosion in catchment areas reduces soil productivity and causes a loss of reservoir *** parametric models have been developed to predict soil erosion at drainage basins,hill slopes and field *** well-known Universal Soil Loss Equation(USLE) represents a standardized *** reservoir,which sits on Chaobaihe River,is the main surface source of drinking water for Beijing,the capital of *** and soil loss are the main reasons for sediment to enter a *** yield is assessed using a version of the universal soil loss equation modified by Chinese *** year 2001 and 2002 data for factors in the equation are obtained from remote sensing or collected to form an analysis *** factors are computed and mapped using Geographic Information System *** on the complex database,the modified model is *** pixel-based computing the sediment yield per hydrological unit is *** model does not consider sediment deposition occurring on *** soil loss is often higher than the sum of those measured at catchment *** sediment delivery ratio(SDR) per hydrological unit is also *** study analyzes the main contributions of sediment yields on sub-basins of the Chaobaihe River to the Miyun Reservoir,and discusses the possible reasons for the difference between SDRs in 2001 and 2002 at different *** result shows that in the upper basin of the Miyun Reservoir,in 2001 the area of erosion that could be neglected was 8,202.76 km2,the area of low erosion 3,269.59 km2,the area of moderate erosion 3,400.97 km2,the area of high erosion 436.89 km2,the area of strong erosion 52.19 km2 and the area of severe erosion 3.13 *** highest soil loss was 70,353 t/*** in Fengning County in 2001,followed by 64,418 t/*** by Chicheng County in *** SDR in 2002 was lower than that in *** main reasons are the decreasing rainfall erosivity and total runoff.

关键词： Modified USLE Gross erosion Sediment delivery ratio

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A Geospatial Approach to Climatic Zone Specific Effective Horticultural Planning in East Khasi Hills District of Meghalaya, India

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Journal of Geographic Information System 2012年第3期4卷 267-272页

作者： Jonali Goswami Dibyajyoti Chutia S. Sudhakar Department of Space North Eastern Space Applications Centre

Climatic zone is one of the most important units for horticultural planning. Survival and failure of particular land use or farming system in a given region heavily relies on careful assessment of agroclimatic resources. Large variety of crops is being grown in Meghalaya traditionally, based on the needs and cultural practices of people without any consideration to the suitability of the climate. This study attempts to make adjustments with the climate based upon scientific knowledge to make the best use of the natural resources so as to recommend more area under horticultural crops. This has been made by identifying existing land use and appropriate land use strategies mainly for horticultural crops for each agro-climatic region. Modern Geospatial technology such as satellite Remote Sensing (RS) and Geographical Information System (gis) and GPS have been used effectively to provide newer dimensions in identifying suitable sites for various horticultural crops and also for appropriate monitoring and management of land resources in an integrated manner with reference to agro-climatic condition.

关键词： Climatic Zone Geospatial Technology RS gis

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一种混沌理论下的需求演化模型

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计算机工程与应用 2010年第22期46卷 68-70,143页

作者：葛君伟葛智方义秋重庆邮电大学gis研究所重庆400065

需求的不确定性和易变性一直是影响软件生命周期,困扰软件开发效率和开发质量的重要因素。通过对动力系统和软件复杂性理论的研究,提出了一种混沌演化模型,该模型可以对软件需求的演化过程进行指导,同时也可以评价需求过程的质量。研究... 详细信息

需求的不确定性和易变性一直是影响软件生命周期,困扰软件开发效率和开发质量的重要因素。通过对动力系统和软件复杂性理论的研究,提出了一种混沌演化模型,该模型可以对软件需求的演化过程进行指导,同时也可以评价需求过程的质量。研究表明,只要需求演化过程的变化图和模型的轨迹图一致,那么需求的演化过程就可以看成是正常的。通过对具体实例的分析,进一步说明了该模型在评价需求演化过程上是有效可行的。

关键词：需求工程需求分析演化模型混沌非线性动力系统

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Evaluating the suitability of TRMM satellite rainfall data for hydrological simulation using a distributed hydrological model in the Weihe River catchment in China

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Journal of Geographical Sciences 2015年第2期25卷 177-195页

作者： ZHAO Haigen State Key Laboratory of Remote Sensing Science Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100875 China Research Center for Remote Sensing and gis Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities School of Geography Beijing Normal University Beijing100875 China South China Institute of Environmental Sciences MEP Guangzhou 510655 China

The objective of this study is to quantitatively evaluate Tropical Rainfall Measuring Mission （TRMM） data with rain gauge data and further to use this TRMM data to drive a Dis- tributed Time-Variant Gain Model （DTVGM） to perform hydrological simulations in the semi-humid Weihe River catchment in China. Before the simulations, a comparison with a 10-year （2001-2010） daily rain gauge data set reveals that, at daily time step, TRMM rainfall data are better at capturing rain occurrence and mean values than rainfall extremes. On a monthly time scale, good linear relationships between TRMM and rain gauge rainfall data are found, with determination coefficients R2 varying between 0.78 and 0.89 for the individual stations. Subsequent simulation results of seven years （2001-2007） of data on daily hydro- logical processes confirm that the DTVGM when calibrated by rain gauge data performs better than when calibrated by TRMM data, but the performance of the simulation driven by TRMM data is better than that driven by gauge data on a monthly time scale. The results thus suggest that TRMM rainfall data are more suitable for monthly streamfiow simulation in the study area, and that, when the effects of recalibration and the results for water balance components are also taken into account, the TRMM 3B42-V7 product has the potential to perform well in similar basins.

关键词： rainfall TRMM distributed hydrological model DTVGM hydrological simulation Weihe River catchment

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多尺度空间关系研究进展

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地球信息科学学报 2015年第2期17卷 135-146页

作者：杜世宏雒立群赵文智郭舟北京大学遥感与gis研究所 61243部队

空间关系及其尺度变化建模,一直是地理信息科学基础理论的重要前沿领域之一。本文全面总结了该领域在理论、方法和应用方面的最新进展。首先,详细阐述了关系表现与几何表现的特点和差异,提出了关系表现的尺度问题,尤其是与制图综合的关... 详细信息

空间关系及其尺度变化建模,一直是地理信息科学基础理论的重要前沿领域之一。本文全面总结了该领域在理论、方法和应用方面的最新进展。首先,详细阐述了关系表现与几何表现的特点和差异,提出了关系表现的尺度问题,尤其是与制图综合的关系。然后,分别结合形状化简、面对象合并、属性归纳、空间维数退化等制图综合算子,论述了拓扑和方向关系尺度变化规律的推导和建模方法。最后,结合多尺度空间关系变化模型,提出了基于关系的多尺度数据分析技术框架,并重点阐述了基于关系的多尺度数据一致性检测和多尺度数据查询的概念及解决方法,且用实例分析证明了它们的有用性。详细而具体地研究不同综合算子对拓扑和方向关系尺度变化的影响及建模方法,对于分析和理解多尺度空间数据,具有重要意义。

关键词：拓扑关系方向关系制图综合尺度变化关系一致性

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一种智能选择多维位置数据的移动定位体系结构

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计算机应用研究 2006年第7期23卷 226-228,231页

作者：胡圣袁正午夏英葛君伟裴海英重庆邮电学院gis研究所重庆400065 韩国仁荷大学计算机信息学院智能型gis研究中心

通过动态获取和发送移动终端相关的位置信息,下一代移动通信网络(3G/4G)能提供一个较广范围的新应用。移动网络现在能越来越准确地确定终端的位置,使得对移动终端提供移动定位服务(MLS)成为可能。提出了一个与定位服务相关的层次模型和... 详细信息

通过动态获取和发送移动终端相关的位置信息,下一代移动通信网络(3G/4G)能提供一个较广范围的新应用。移动网络现在能越来越准确地确定终端的位置,使得对移动终端提供移动定位服务(MLS)成为可能。提出了一个与定位服务相关的层次模型和一种支持互联网及定位导航的定位服务体系结构,移动用户可以根据其当前的需要选择不同类型的位置数据输出。

关键词：语义位置数据时空位置数据地理位置数据 3G/4G LBS

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Spatial changes of wind erosion-caused landscapes and their relation with wind field in China

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Journal of Geographical Sciences 2002年第2期12卷 30-39页

作者： Zhang Guo-ping Liu Ji-yuan Zhang Zeng-xiang Zhao Xiao-li Zhou Quan-bin Institute of Remote Sensing applications CAS 北京 100101 Institute of Geographic Sciences and Natural Resources Research CAS 北京 100101

Based on the results of remote sensing investigations of the landscapes of 1995 and 2000, the national distribution of sandy desertified land and its interaction with other landscapes are classified, and five zonal types are distinguished. The data of nationally distributed 400 meteorological stations of 1999 are processed. With the gis method, the data are spatially interpolated, and the national database of wind field concerned with wind erosion is established. In arid and semi-arid areas of China, the intensity of wind field is one of the key factors that controls the development of landscape especially in desert and its adjacent area. Different indexes are set up to describe the intensity of wind field, the method suggested by the wind erosion prediction models of RWEQ is also adopted to express the intensity of wind. The Weibull distribution is used to describe the wind field in China. Based on the analysis of the process of the wind erosion-driven landscape changes, this article proposes and discusses the control measures of wind erosion.

关键词： remote sensing sandy desertification Weibull distribution desertification control in China wind energy

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基于多模态元数据的Videogis解决方案

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计算机应用 2008年第B6期28卷 337-339,343页

作者：邹永贵谢萍丰江帆重庆邮电大学中韩gis研究所重庆400065

提出视频gis的概念模型与实施方案,分析了一个基于实时可定位信息自动融合与多模态元数据提取技术的视频gis原型系统——Videogis。讨论了该系统的目标及体系结构,描述了其中涉及的关键技术思想,并对进一步的研究方向作了展望。

关键词：视频gis 空间定位信息元数据多模态索引

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基于滑动窗口的关联规则增量式更新算法

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计算机应用 2008年第12期28卷 3224-3226页

作者：夏英刘婉蓉重庆邮电大学中韩gis研究所重庆400065

现有的关联规则算法大多都致力于解决增量式更新问题,需要多次扫描数据集,无法对海量数据进行有效处理。针对此问题,提出了基于滑动窗口的关联规则增量式更新算法(SWIUA),利用滑动窗口进行数据更新,挖掘出用户感兴趣的关联规则。该算法... 详细信息

现有的关联规则算法大多都致力于解决增量式更新问题,需要多次扫描数据集,无法对海量数据进行有效处理。针对此问题,提出了基于滑动窗口的关联规则增量式更新算法(SWIUA),利用滑动窗口进行数据更新,挖掘出用户感兴趣的关联规则。该算法只需要扫描原始数据集和更新的数据各一遍,降低了I/O时间;并采用优化策略对候选项集过滤和删除,提高了关联规则的挖掘性能,能有效处理大量新增数据。

关键词：滑动窗口关联规则增量式更新频繁项集

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