最新刊期
卷 ， 期 4 ， 1998
- 摘要：A Stereopair positioning algorithm based on "Equivalent Line Central Projection" is presented for SAR Images in this paper. Then the accuracy potential is analyzed. The theoritical error models and the experimental results show that the main factors affecting the accuracy are radargrammetric configurations and the measured errors in range direction.关键词：SAR Images;Image forming equations;Stereopair positioning;Accuracy analysis model
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发布时间：2021-06-10 - 摘要：Spatial information encoding which presents the interface between the real and information entities, is one of the most important steps in designing GIS. Most GIS and mapping systems almost adopt the ways of encoding for geographical attributes, which are more effective for spatial analyses but weaker in mapping. Referring to the other coding methods such as AutoCad and MapCad, the authors raised the concepts of geographical entity encoding model（GEEM） and cartographic entity encoding model （CEEM）, and compared their advantages and disadvantages in mapping. A new model, coupled geographical-cartographic attributes encoding model （CGCEM）, has been proposed based on the two models mentioned above.关键词：Information encoding model;GIS;Mapping
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发布时间：2021-06-10 - 摘要：Remote sensing ground feature extraction is a key to remote sensing applications. AS the Remote sensing applications advance, various thematic information extraction methods and models have been researched upon and developed. In recent years, intellectual information extraction has become the focus of remote sensing specialists, as artificial intelligence advances in the computer field. The main objective of this paper is to develop a new method for extracting remote sensing information intellectually. Firstly, a knowledge-based model for thematic information extraction will be developed on the basis of remote sensing information mechanism study; Secondly, the model has been set up under the direction of OO idea and so a broad-sense knowledge-based method is used. The above intellectual information extraction method is illustrated with an example of water recognition automatically from NOAA/AVHRR. Satisfied results have been achieved when this method is applied to identify natural water and newly flooded areas. Finally, flood disaster monitoring has also been experimented in this way.
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发布时间：2021-06-10 - 摘要：In this paper,the authors present a technique of watershed structure extraction and watershed partition automatically based on gird digitial elevation model（DEM） data . This technique consists of three parts:definition of topographic structure; topographic structure; definition of watershed structure; and algorithm design which is used to extract the characteristics of topography from DEM data. The authors consider that the channel network and the divided network as the two basic frameworks of a watershed. The polygons constructed by the above networks are corresponding to the catchments which make up the watershed. The framework consisting of these catchments, the basic topographic units, and their topologic relationship can be used to store the watershed information and to construct spatial distributed mechanism-course models. The watershed of Wangjiagou in Lishi Gounty of Shanxi Province, located in a gully area in loess plateau, was selected as a pilot study area, and the final results are in accordance with the real condition of the case study area.关键词：digital elevation model;topographic structure;Watershed structure;Algorithms
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发布时间：2021-06-10 - 摘要：As the satellite remote sensing data have been available since early 1990s, these data are being employed towards the improvement of vegetation classification. On macro and middle scale of vegetation remote sensing, NOAA AVHRR possesses an advantage when compared to other satellite data On the other hand, because the scanning width of NOAA AVHRR is so large （2800km）, the earth’s curvature, characteristics, the angle of reflection from earth’s object and atmosphere as well as the angle of scanner and deviation of sun’s height cause a serious effect on the data. Therefore, NOAA AVHRR also has problems of low resolution, data distortion and geometrical distortion. AS a result, applying NOAA AVHRR to large scale vegetation-mapping, the accuracy of vegetation classification should be increased. This paper discusses the feasibility of integrating the geographic and remotely sensed data in GIS. Under the GIS environment,temperature, precipitation and elevation, which serve as main factors affecting vegetation growth, were processed by a mathematical model and qualified into geographic image under a certain grid system. The geographic image were overlaid to the NOAA AVHRR data which had been compressed and processed. In order to evaluate the usefulness of geographic data for vegetation classification,the area under study was digitally classified by two interpreter methods. A maximum likelihood classification assisted by the geographic database, and a conventional maximum likelihood classification only.Both results were compared using Kappa statistics. The indices to both the proposed and the conventional digital classification methodology were 0.668（very good） and 0.563（good）, respectively. The geographic database rendered an improvement over the conventional digital classification. Furthermore, in this study, some problems related to multi-sources data integration are discussed.关键词：NOAA AVHRR;NDVI;Geographic image;Integrated image;remote sensing;Supervised classification;GIS
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发布时间：2021-06-10 - 摘要：The detection of bay’s primary productivity using remote sensing is presently based on the spectrum of chlorophyll. However, this method is not precise because of the interference caused by silt suspension and the surface wave. The paper presents a method based on GIS which make our remote sensing model on primary productivity with mutual-compensated parameters satisfactory. These parameters, with mutual compensation characteristics for the chrolophyll spectrum on remote sensing, has greatly helped to improve the model. Our test in the Daya bay has shown that the precision has greatly increased from an error of 6.5% to 0.26%, thus proving this method feasible and practical.关键词：Remote sensing;Primary productivity;Mutual-compensated parameter
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发布时间：2021-06-10 - 摘要：The Microwave radiometer is a kind of passive microwave remote sensor. Generally microwave radiometer can be considered as passive receptors of radiation from objects with no energyradiated from the antenna to its surroundings practically the components of radiometers have thermal noise and radiate energy in the reverse direction. In another case, the reverse radiation comes from the mismatch of the components between the antenna and the receiver system. The energy radiated to the outside through the antenna is reflected by the objects and received by the antenna again. The value of revising radiative temperature is linked to the noise of the receiver and components of the receiver front-end. The reverse radiative temperature in the system will affect the accuracy of the microwave radiometer calibration and the ground-based microwave radiative measurements near nadir angle.关键词：Microwave radiometer;Reverse radiative temperature
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发布时间：2021-06-10 - 摘要：Radiometric calibration of satellite-acquired data （visible, near-infrared and thermal infrared） is essential for quantitative scientific studies, as well as for a variety of quantitative appications. In the spectral region of thermal infrared,the effects of atmospheric water vapor and aerosols on the retrievalsof surface temperature are the two primary factors. From Landsat-5 TM6 image data acquired at Dunhuang site on September 25 1995, we made adjustments for atmospheric effects and derived the land surface temperatures using the spectrally corrected LOWTRAN-7 code. Using LOWTRAN-7 code, we also analyse the effects of atmospheric water vapor and aerosols on the retrieved surface temperatures by simulative calculations. Finally, we provided an explanation for what kinds of atmospheric conditions, even without considering the foreknown influence of the atmosphere, properly calibrated thermal infrared data can provide accurate remote temperature measumments, and determined under what meteorologic conditions, making corrections for atmospheirc effects is in need. This paper, at the end, also discussed the emissivity effects on the derived surface temperature.关键词：Atmospheric correction;Thermal infrared;radiative transfer model;Suuface emissivity;Temperature retrieval.
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发布时间：2021-06-10 - 摘要：In the processing of Synthetic Aperture Radar （SAR） Images, a large window size, which is often used in estimating the local statistics of the image and filtering the speclke is needed. On the other hand, contrary, detection of edges and textural features often need small sized windows. Normal filters, which are intermediary ofthe two above, don’t give better results. This paper presents a new effective algorithm to solve the problem. In this method, the edges and the textural features of the SAR images are presented so the the problem of edge smearing in the normal filtering algorithm is avoid and the speckles are filtered effectively.关键词：SAR;Local statistics;speckle;Edge and texture feature;Window size
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发布时间：2021-06-10 - 摘要：In view of the existing problems in the study of forest site type classification and site quality evaluation ,based on the ecology and landscape ecology theory, this paper deals with a new method to accomplish the forest site type classification,site quality evaluation, and automatic mapping in Beijing region using Remote Sensing（RS）, GIS, Expert System（ES） and other relevant mathematical statistics analysis. First, the principles and system of classification are determined, according to the requests of application, the results of qualitative analysis to the features of landscape, climate, landforms, terrain, soil and vegetation, qualitative and quantitative analysis to the first type and the second type survey data. Secondly, setting up the thematic maps and attributes data bases of all factors of different classification levels using GIS as platform, and accomplishing the pre-classification of every level by overlaying the thematic maps. Thirdly, with the aid of expert knowledge stored in the knowledge base and the inference mechanism of ES, compiling the pre-classification maps in the light of the conference theory; Finally, assessing the site quality of every site type using scores of the factor indices given by the experts, and creating the evaluation maps. Based on the classification and evaluation results, the users can select different sets of objects which can integrate the ecological, economic, environmental and social benefit of forest, and implement the object-oriented dynamic decision-making.关键词：Site type classification;Site quality evaluation;Multi-object dynamic decisionmaking;RS;GIS;ES
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发布时间：2021-06-10 - 摘要：This paper shows a new idea of establishing the digital environment model using remote sensing and GIS techniques. We used order numerical array for building the digital environment model,and quantitatively assessed the ecological environment situation of central Tibet.It focuses on model building and method realization. First, an idea of digital environment mode has been suggested Then, how to use this model to establish environmental monitoring and environmental quality assessment has been fourth discussed.关键词：GIS;Digital environment Model
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发布时间：2021-06-10 - 摘要：Imaging spectrometer combines two dimensional imaging technology and spectrometer technology, and it is a promising instrtument for earth observation. With the development of technology of pushbroom imaging with focal plain detectors, hyperspectral imager was developed as an advanced remote sensing instrtument in recent years and it becomes another grow point of imaging spectrometer technology. As increase of the demand of environment study and city planning, Pushbroom Hyperspectral Imager （PHI） was built under the cooperation of Shanghai Institute of Technical Physics, Chinese Academy of Sciences, and Shanghai Senstron Institute of Information Technology. PHI uses Si CCD as focal plain detector. It has a field-of-view of 21 degrees with spatial resolution of 1.5 mrad, and 244 spectral bands covering from 0.40 to 0.85 micrometer in wavelength with spectral resolution better than 5nm in full range. This paper discuses the key technology of PHI,including critical components, system calibration, ground reflectance and radiation calculation and multi-system integration. The image taken by PHI in remote sensing operation for city planning of Beihai, Guangxi province, is also given.关键词：remote sensing;Imaging spectrometer;Hyperspectrum;Hyperspectral imager
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发布时间：2021-06-10 - 摘要：The Normalized Difference Vegetation Index （NDVI） departure data set in East China monsoon region （108-123°E, 21-45°N） in 1986 was established with NOAA/NASA Pathfinder AVHRR Land data set .The principle component analysis （PCA） was implemented on this data set .The temporal curves and spatial fields of the first and second principle components expose the significant characteristics of vegetation phenology in seasonality and spatial patterns in East China monsoon region. In the area south to Nanling-Wuyi Mountains, there are not very clear vegetation seasonal variations. However, obvious seasonal phenological features in whole growing season exist in the areas north from Nanling-Wuyi Mountains. In Huabei Plain which locates in the north of Huai River Valley, phenology is distinguished with the double peak growing process. Though the similar double peak growing process also happens, there are more continuous characteristics of vegetation growing in the south of Huai River Valley. Huai River Valley forms a transitional zone of vegetation seasonal phenology.关键词：East China Monsoon Region;phenology;vegetation index
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发布时间：2021-06-10 - 摘要：Drought is a major kind of natural disaster that severely influences agricultural production, especially on the growing spring wheat in boreal China. This paper introduces a method and software which use Remote Sensing and GIS technique to monitor drought of spring wheat in Great East Plain of China. This method applies thermal inertia model and CWSI model to estimate soil moisture with NOAA/AVHRR data and meteorological observation data. Under the support of GIS technique, monitoring result is presented by a map which expresses the spatial distribution of different drought levels, as well as a statistic form which shows the area and percentage of various drought degrees in each county. This software system has been operated for three years since 1994. Tested and verified by observation data,the monitoring result has 83.6% precision in average.关键词：Remote sensing;GIS;NOAA/ AVHRR;Drought monitoring
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发布时间：2021-06-10
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