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A static and dynamic factorscoupled forecasting model of regional rainfall-induced landslides:A case study of Shenzhen

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Science China(Technological Sciences) 2008年第S2期51卷 164-175页

作者： JIA GuiYun,TIAN Yuan,LIU Yu & ZHANG Yi institute of remote sensing and gis,peking university,Beijing 100871,China institute of remote sensing and gis Peking University Beijing China

Most rainfall-induced landslide forecasting models focus on the relation between landslides and rainfall,which is one of the dynamic factors,and seldom consider the stacitc factors,such as geological and geograpical *** susceptibility,however,is determinded by both static and dynamic *** article proposes a static and dynamic factors-coupled forecasting model(SDFCFM) of regional rainfall-induced landslides,which quantitatively considers both the static and dynamic factors that affect *** generalized additive model(GAM) is applied to coupling both factors to get the landslide *** the case study,SDFCFM is applied to forecast the landslide occurrences in Shenzhen during a rainfall process in *** with the rainfall logistic regression model,the resulting landslide susceptibility map illustrates that SDFCFM can reduce the forecast redundancy and improve the hit *** is both applicable and *** application of SDFCFM in landslide warning and prevention system will improve its efficiency and also cut down the cost of human and matreial resources.

关键词： regional rainfall-induced landslides static and dynamic factors-coupled forcasting model(SDFCFM) generalized additive model(GAM) landslide susceptibility

The correlation of multi-angle thermal infrared data and the choice of optimal view angles

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Science China Earth Sciences 2004年第6期47卷 570-576页

作者： FAN Wenjie1 & XU Xiru1,2 1.institute of remote sensing and gis of peking university,Beijing 100871,China 2.Center of remote sensing and gis of Beijing Normal university,Beijing 100875,China institute of remote sensing and gis of peking university Beijing China Center of remote sensing and gis of Beijing Normal university Beijing China

Based on the matrix formula of thermal infrared radiant system, the components temperature can be retrieved by the inversive matrix. Around the stability problem of retrieved result, the research work we did was focused on (i) the correlation of (wk,j) which is the key to affect the retrieval accuracy, (ii) a general method which can help us find the number of retrievable parameters and evaluate the retrieval error before its performance, (iii) the choice of “optimal viewing angle group” based on the formula of absolute error propagation. The row winter wheat field was chosen as an example. The results can provide a theoretical basis for multi-angle thermal infrared remote sensing and components temperature retrieval.

关键词： components temperature retrieval, correlation, number of retrievable parameters, optimal viewing angle group.

The spatial scaling effect of continuous canopy Leaves Area Index retrieved by remote sensing

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Science China Earth Sciences 2009年第3期52卷 393-401页

作者： XU XiRu FAN WenJie TAO Xin institute of remote sensing and gis Peking UniversityBeijing 100871China

Leave Area Index (LAI) is one of the most basic parameters to describe the geometric structure of plant canopies. It is also important input data for climatic model and interaction model between Earth surface and atmosphere, and some other things. The spatial scaling of retrieved LAI has been widely studied in recent years. Based on the new canopy reflectance model, the mechanism of the scaling effect of con- tinuous canopy Leaf Area Index is studied, and the scaling transform formula among different scales is found. Both the numerical simulation and the field validation show that the scale transform formula is reliable.

关键词： spatial scaling effect remotely sensed LAI the true LAI the reflectance model of continuous canopy

Incorporating DeepLabv3+and object-based image analysis for semantic segmentation of very high resolution remote sensing images

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International Journal of Digital Earth 2021年第3期14卷 357-378页

作者： Shouji Du Shihong Du Bo Liu Xiuyuan Zhang institute of remote sensing and gis Peking UniversityBeijingPeople’s Republic of China

Semantic segmentation of remote sensing images is an important but unsolved problem in the remote sensing *** image semantic segmentation models,such as DeepLabv3+,have achieved astonishing performance for semantically labeling very high resolution(VHR)remote sensing ***,it is difficult for these models to capture the precise outlines of ground objects and explore the context information that revealing relationships among image objects for optimizing segmentation ***,this study proposes a semantic segmentation method for VHR images by incorporating deep learning semantic segmentation model(DeepLabv3+)and objectbased image analysis(OBIA),wherein DSM is employed to provide geometric information to enhance the interpretation of VHR *** proposed method first obtains two initial probabilistic labeling predictions using a DeepLabv3+network on spectral image and a random forest(RF)classifier on hand-crafted features,*** two predictions are then integrated by Dempster-Shafer(D-S)evidence theory to be fed into an object-constrained higher-order conditional random field(CRF)framework to estimate the final semantic labeling results with the consideration of the spatial contextual *** proposed method is applied to the ISPRS 2D semantic labeling benchmark,and competitive overall accuracies of 90.6%and 85.0%are achieved for Vaihingen and Potsdam datasets,respectively.

关键词： Semantic segmentation DeepLabv3+ object-based image analysis DempsterShafer evidence theory conditional random field VHR images

A bi-directional gap model for simulating the directional thermal radiance of row crops

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Science China Earth Sciences 2002年第12期45卷 1087-1098页

作者： CHEN Liangfu LIU Qinhuo FAN Wenjie LI Xiaowen XIAO Qing YAN Guangjian TIAN Guoliang LARSIS Institute of Remote Sensing ApplicationsChinese Academy of SciencesBeijing 100101China institute of remote sensing and gis Peking UniversityBeijing 100871China Research Center of remote sensing and gis Beijing Normal UniversityBeijing 100875China

Row crops are a kind of typical vegetation canopy between discrete canopy and continuous *** et *** the directional thermal radiation of row crops using the geometrical optical model,which simplified row structure as'box'and neglected the gap among foliage and did not consider the emissivity *** this work we take account of the gaps along illumination and viewing directions and propose a bi-direction gap model on the basis of the idea of gap probability of discrete vegetation canopy introduced by'Li-Strahler'and inter-correlation of continuous vegetation developed by *** can be used to explain'hot spot'effects in thermal infrared *** gap model has been validated by field experiment on winter wheat planted in shape of rows and results show that the gap model is better than Kimes'model in describing the directionality of thermal infrared emission for row crops.

关键词： row-structure gap model directional thermal radiation hot-spot effects

Integrative inversion of land surface component temperature

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Science China Earth Sciences 2005年第11期48卷 2011-2019页

作者： FAN Wenjie1 & XU Xiru1,2 1. institute of remote sensing and Geographical Information System, peking university, Beijing 100871, China 2. Center of remote sensing and gis of Beijing Normal university, Beijing 100875, China institute of remote sensing and Geographical Information System Peking University Beijing China Center of remote sensing and gis of Beijing Normal university Beijing China

In this paper, the row winter wheat was selected as the example to study the com-ponent temperature inversion method of land surface target in detail. The result showed that the structural pattern of row crop can affect the inversion precision of component temperature evi-dently. Choosing appropriate structural pattern of row crop can improve the inversion precision significantly. The iterative method combining inverse matrix was a stable method that was fit for inversing component temperature of land surface target. The result of simulation and field ex-periment showed that the integrative method could remarkably improve the inversion accuracy of the lighted soil surface temperature and the top layer canopy temperature, and enhance inver-sion stability of components temperature. Just two parameters were sufficient for accurate at-mospheric correction of multi-angle and multi-spectral thermal infrared data: atmospheric trans-mittance and the atmospheric upwelling radiance. If the atmospheric parameters and component temperature can be inversed synchronously, the really and truly accurate atmospheric correction can be achieved. The validation using ATSRII data showed that the method was useful.

关键词： components temperature, inverse pattern, atmospheric correction

Matrix expression of thermal radiative characteristics for an open complex

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Science China Earth Sciences 2002年第7期45卷 654-661页

作者：徐希孺范闻捷陈艮富 Center of remote sensing and gis of Beijing Normal university Beijing China institute of remote sensing Peking University Beijing China Laboratory of remote sensing Information Sciences Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China

The directionality of thermal radiance of a homogeneous isothermal non-black plane surface is totally decided by its directional emissivity, which depends on the complex dielectric constant and roughness of surface. It can be expressed by $\bar L_\lambda (\theta _k ,T) = \bar \varepsilon _\lambda (\theta _\lambda )L_{b\lambda } (T)$ . This paper proves that it is necessary to express emissivity by a matrix when a target becomes an inhomogeneous non-isothermal open complex with complicated inner geometric structure. The matrix describes the inner radiative interaction among components accurately and also expresses its thermal radiative directionality and structural characteristics completely. Advantages of matrix expression are as follows: first, the physical mechanics of effective emissivity of an open complex is described in a simple and perfect way; second, it becomes easy to understand the principle and method to retrieve components temperature from multi-angle thermal remotely sensed data; and third, the differences of directionalities between an open complex and a homogeneous isothermal non-black plane body are expressed by just using an effective emissivity matrix instead of an emissivity vector. Formula $\bar L_\lambda (\theta _k ,T) = \varepsilon _\lambda (\theta _\lambda )L_{b\lambda } (T)$ in classic physics is only the special case of matrix expression; therefore, the matrix is a universal unconditional expression to describe the directionality of thermal radiance.

关键词： open complex, directionality of thermal radiance, structural characteristics of thermal radiance, matrix expression.

An IconMap-based exploratory analytical approach for multivariate geospatial data

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Science China(Information Sciences) 2013年第1期56卷 198-207页

作者： ZHANG XianFeng LIAO ChunHua LIU Yu LI Jonathan institute of remote sensing and gis Peking University Department of Geography and Environmental Management University of Waterloo

This paper discusses an iconmap-based visualization technique that enables multiple geospatial variables to be illustrated in a single gis raster *** is achieved by extending the conventional pixelbased data structure to an iconic *** this way,spatial patterns generated by the interaction of geographic variables can be disclosed,and geospatial information mining can be readily *** a case study,a visual analysis of soil organic matter and soil nutrients for Shuangliu County in the city of Chengdu,China,was undertaken using the prototype IconMapper software,developed by the *** results show that the static IconMap can accurately exhibit trends in the distribution of organic matter and nutrients in *** dynamic iconmap can both reflect interaction patterns between organic matter and the nutrient variables,and display soil fertility levels in a comprehensive ***,the iconmap-based visualization approach is shown to be a non-fused,exploratory analytical approach for multivariate data analysis and as a result is a valuable method for visually analyzing soil fertility conditions.

关键词： iconmap soil fertility visualization icon blocks multivariate geospatial data

Study on the law of radiant directionality of row crops

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Science China(Technological Sciences) 2000年第S1期43卷 70-82页

作者：陈良富庄家礼柳钦火徐希孺田国良 Insitute of remote sensing and gis Peking University Beijing China institute of remote sensing Applications Chinese Academy of Sciences Beijing China

The style of crops planting is frequently in row-structure, the row-structure style may result in big difference among the sunlit, shaded soil surface and foliage temperatures and cause pixel component to vary in azimuth orientation, these further lead to the change of radiant directionality of row crops in the zenith and azimuth orientations. Since the row crops are often tackled as isotropic in the azimuth orientation based on continuous vegetation assumption, big errors will be brought about. In order to eliminate the errors, it is necessary to study the law of radiant directionality of the row crops. In this paper, Monte Carlo method has been employed to simulate the angular effects on radiation caused by row architecture parameters. The simulated results show that the parameters, for example, row height, row width, row interval between the neighbor rows and the leaf area index have significant influences on the radiant directionality, but the azimuth orientation ranks the first among the parameters.

关键词： row crops radiant directionality Monte Carlo simulation.