最新刊期
卷 ， 期 5 ， 2001
- 摘要：The application of Chinese meteorological satellites FY 1 and FY 2 in monitoring global forest resources is introduced. The new strategies for global forest resources re allocation are discussed when China joins the WTO. The Green Great Wall--"Tri North" Shelter Belt in the new century and the effect of forest on the global environmental change are also discussed. From the global viewpoint, the forest resources strategy facing the WTO is discussed. The forest resource is very poor, but its daily consumable amount is very large, for example, Chinese chopsticks, packing box of the shirts and the Oriental Set Board ect. Therefore, actions must be taken to protect ecologic environment. Every country now has known that forest resource is very important to global environment protection. An example of this is to recover plowland to forest and grassland in order to abate CO 2 emission. National Natural Reserves and Protected Areas give some good demonstrations of protecting eco environment. The characteristic of forest in Fanjing Mount. in Guizhou Province of China and its special contribution to the world demonstrate the forest role in environmental protection. The planning and construction of Chinese forest resources database and forest management information system are proposed for the 21st century. Digital Earth can be used to monitor forest dynamic change and establish "Digital Forestry" information system. We should apply the power of Digital Earth, and protect "the Lung of the Earht"--global forest resources. It is a huge information system project to set up "Digital Forestry". Since our country established, the Chinese departments of forestry survey, planning and administration have accumulated plenty of data and investigation information, and made many surveys by Remote Sensing and gained experiments by using information system. The establishment of the digital forestry system will promote the use of the data, share and co construct resource and environment data, and standardize the release and exchange of Chinese forestry information. By these, China will make contribution for monitoring forest dynamic change using "the Digital Earth".关键词：vegetation index;re allocation of forest resource;natural reserves and protected area;forest management information system
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发布时间：2021-06-10 - 摘要：The Li-Strahler Geometry Optical Mutual Shadow（GOMS）model is a simple, yet efficient mechanism for modeling forest canopies as arrays of three-dimensional objects. In GOMS model, the signal received by the sensor is modeled as consisting of reflected light from tree crowns, their shadows and the background within the field of view of the sensor. The model is intrinsically bound to the influence of variation in viewing and illumination geometry, and may be inverted to recover biophysical parameters. However,because the GOMS model is a nonlinear model,difficulties exist to invert it. In this paper, a Modified Genetic Algorithm（MGA） are introduced for the inversion. Compared with the deterministic search method-Sequential Quadratic Programming（SQP）,MGA can quickly find promising regions of the search space, but may take a relatively long time to reach the optimal solution. In contrary, SQP can converge to an extreme value quickly, but whether the result is optimal or not depends greatly on the initial value. For this reason, a mixed method is used to invert GOMS model in some cases. The result obtained by MGA is inputted to SQP as initial value. This method significantly increases the power of MGA in terms of solution quality and speed of convergence to the optimal.关键词：genetic algorithm;GOMS model;Retrieval;sequential quadratic programming
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发布时间：2021-06-10 - 摘要：This study presents a mechanism analysis to the response of leaf spectrum result from trace elements. A wide range of leaves were collected including variations in species and leaf status. The biochemistry composition was measured using ICP-AES techniques to determine Fe, Mn, Cu, Zn, Co, Cr, Mo and B contents. Concurrently, leaf reflectance was measured with a high spectral resolution spectrophotometer in the 400-2500 nm range with approximately 1.1 nm spectral resolution. Trace elements are helpful to natural growth of vegetable, and the detection in trace elements’ status is an important approach to find out growth condition of vegetable. The study for trace element and spectral characters is one of important methods in quantitative remote sensing. In this paper, spectrum data and trace elements are firstly analyzed using different techniques, and in the end the relationship was studied between trace elements and leaf spectrum, and differential coefficient spectrum. Result shows that Co content is strongly correlative with leaf spectral relfectivity negatively in around 569.22 nm. In addition, Mn, B, Mo and Zn are in good consistent with absorption features of leaf spectrum in （0.4, 1.16）, （0.47, 0.88, 2.19, 2.34）, 1.62 and 2.34 μm. Its’ mechanism is discussed chiefly other than only discovering the location of leaf spectrum response resulted from different trace elements.关键词：leaf spectrum;trace element;characteristic absorption;spectrum response
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发布时间：2021-06-10 - 摘要：Rice monitoring and production estimation has special significance to China, as rice is the staple grain and accounts for 42% of the crop production for this country. Radar remote sensing is appropriate for monitoring rice as cultivated areas are most often cloudy and rainy. SAR is anticipated to be the dominant remote sensing data source with high resolution in tropic and subtropical regions. It also provides revisit schedules suitable for agricultural monitoring. This paper presents the results of a study examining the backscatter behavior of rice as a function of time using multitemporal RADARSAT data set acquired in 1996 and 1997. A ricetype distribution map was produced, showing 4 types of rice with different life spans ranging from 80 days, to 120125 days. The life span of a rice crop has significant impact on yield, as well as the taste and quality of the rice. The rice production of three counties and two administrative regions, totaling 5000 square kilometers, are estimated in this study. The accuracy was found to be 91%, providing confidence that multitemporal RADARSAT data is capable of rice monitoring and production estimation. Based on the studies carried out in the Zhaoqing test site since 1993, it is suggested that rice production estimations require three radar data acquisitions taken at 3 stages of crop growth season. That is at the end of the seedling development period, in the ear differentiation period, and at the beginning of the harvest period. Alternatively, if multiparameter radar data is available, data acquisitions may reduce to only two. That is at the end of the seedling period, and at the beginning of the harvest period. This paper also proposes a pilot scenario for operational rice monitoring and production estimation.关键词：radar;backscatter coefficient;rice;time domain analysis;production estimation
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发布时间：2021-06-10 - 摘要：Remote sensing provides a viable source of data from which land use/cover changes information can be extracted efficiently and cheaply. During the past two decades, there has been a growing interest in the development of change detection technique based on remote sensing data, and a number of techniques for accomplishing change detection using satellite image data have been formulated, applied, and evaluated. As a direct spectral comparison approach, change vector analysis （CVA） is an effective method for land use/cover detection. Based on the method named as Double-Windows Flexible Pace Searching for change magnitude threshold determination, which was proposed in the previous paper, the change pixels have been detected successfully from the TM image in 1991 and 1997. This paper presents new methods of determining change direction （change type） which combines single image classification and minimum distance categorizing based upon change vector direction cosine. Furthermore, This new method is applied to land use/cover change detection in the image of Haidian district of Beijing and the result is satisfactory. The overall precision rate of distinguishing change type arrives above 70%. It shows that the new method have many advantages and is practicable.关键词：change vector analysis land use/cover;change type determining;change vector direction cosine;minimum distance categorize
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发布时间：2021-06-10 - 摘要：Remote sensing images have both spectral and textural features. How to make uses of these features is very important to the practical work of remote sensing image classification. This paper presents a supervised classification method of aerial remote sensing image, which takes advantages of both spectral features and textural features. First, this paper puts forward a set of textural features with their computation approaches based on fractal and multifractal theory, including fractal dimension, multifractal function %qD（q）%, and lacunarity. The fractalbased textural features are relatively insensitive to the image scaling, therefore, within certain scope, the fractalbased textural features obtained from a remote sensing image under one resolution can also be used in the remote sensing images under other resolutions. This is very valuable in practice. Then, this paper presents the classification method which consists of two parts, namely feature extraction and classifier construction. In the part of feature extraction, this method converts color aerial image from RGB to HSI and computes fractal dimension, multifractal function %qD（q）%, and lacunarity by intensity as texture features with normalized hue and saturation being used as spectral features. In the part of classifier construction, it adopts BP neuval network as classifier. In the end, the experiment of classifying the aerial images has been done and the result is satisfactory, which verifies the effect of this methood.关键词：aerial image;image classification;Texture;Fractal;neural network
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发布时间：2021-06-10 - 摘要：Requirements analysis is an important step in an information system development cycle. It can be viewed as a process with a life-cycle of its own. The requirements analysis may includes four more basic step: domain-problem analysis, problem description, prototyping and testing, validation. It is also an iterative and evolutionary process, and a concurrent activity. Therefore, the requirements analysis model should represent the iterative, evolutionary and concurrent characteristics of requirements process activities. However, most of models resently developed only represent one or two characters of requirements process activities. The waterfront model for requirements analysis which was put forward by Theofanos can represent all characters of requirements process activities. In this paper the authors improve this model according to the characters of GIS requirements analysis activities in following aspects: ① In order to develop ulteriorly the automatous tool of GIS requirements analysis in term of the model, the requirements analysis was partitioned into five basic activities: problem analysis, structural requirements description, formal requriements definition, prototyping and testing, validation. ② In order to make the model more operational, analysis methods for every activities of requirements analysis is put forward. ③ The difference of requirments analysis for project GIS, department GIS, enterprise GIS and social GIS is presented and also incorporated into the model. The methods for GIS structural requirements analysis are also discussed. This will have a guideline significance for GIS requirements analysis.
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发布时间：2021-06-10 - 摘要：The penetrability of electromagnetic radiation is limited, generally the penetrability depth of the microwave is less than 5m, which is called ’skin depth’. However it is very important for us to know the depth of structure in remote sensing images. Generally it can be acquired by overlying the continuous contour of gravity and magnetic data on to remotely sensed images or integrating remotely sensed and gravitational and magnetic data. But this is qualitative and indirect method. A new method, Euler Deconvolution is introduced in the paper. The structure location, stretch and depth could be estimated by using Euler Deconvolution of geophysical data. And the depth of structure in remotely sensed images could be displayed by overlying the Euler Deconvolution results on to the remotely sensed images. The method was applied in the western slope of SongLiao Basin, which is quantitative and more efficient than other geophysical methods. And the depth of structure in remotely sensed images cannot be estimated except geophysical methods.
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发布时间：2021-06-10 - 摘要：Newly SOTER database management system is established based on completenewly object oriented software development method and rigorous development process of analyzing, designing, coding and examining. The new one has the following advantages: （1） inheriting and enlarging attribute data management function of original SOTER, and enhancing the integrith and safety of SOTER; （2） integrating the attribute database, spatial database and model base into a unique system, and using the windows graphic user interface （GUI）, as interactive tools which make establishment and maintenance of SOTER database convenient; （3） promoting the quantitativity, model standardization and automation of soil information, and serring as a good example for building new soil databases and information system.关键词：object oriented;SOTER;database;Model;analysis and design
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发布时间：2021-06-10 - 摘要：Dust storm hits North China many times during the spring in 2000, bringing adverse influence on the activities of both production and living. It is an effective technological method used to monitor the process of the dust, to research the spatial characters, and to analysis the undersurface of the dust by means of Remote Sensing and GIS. The scope and characters of dust storm ever having happened could be acquired by analyzing over twenty temporal images received by remote sensing satellite when the storm happened and proceeded. The region influenced directly by dust storm is estimated to be about two million square kilometers. Inner Mongolia, Hebei, Beijing, and Tianjing are the regions influenced by dust storm most frequently. In this article land use and its recent changes, soil characters, vegetation coverage, soil erosion, and natural environment of the region which dust storm passed through are put together to analyze by overlying the remote sensing data and spatial data. Dust storm in North China has a Multisource character. The region where this kind of damage concentrates has a spatial coherence with the Farmpasture region, the water and wind erosion region and the half drought region in North China. The increasing of human activity has a direct influence on the forming of dust storm. Then there comes the conclusion that the time and spatial characters of the environment that gives birth to the dust storm can be entirely known by people through Multisubject spatial data analysis. This analysis can provide objective spatial information in time for the establishment and actualizing of the laws about natural environment protection in order to release, or even avoid the dust damage. It also plays an important role in reducing the times that dust storm appears and decreasing the damage brought by this disastrous weather.关键词：dust storm;remote sensing;groundsurface
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发布时间：2021-06-10 - 摘要：Taiwan Strait is a shallow shelf channel linking the East China Sea （ECS） and the South China Sea （SCS）. During winter monsoon, cold Min-Zhe Coastal Water （hereafter MZCW） rich of nutrients generally dominates the northern Taiwan Strait; warm oligotrophic Kuroshio water （hereafter KW） and Soiuth China Sea Water （hereafter SCSW） from SCS intrude into the southern Taiwan Strait. Nevertheless, Kuroshio intrusion into the Taiwan Strait was found to be stronger than usual during winter monsoon of 1998, as observed by a satellite instrument, AVHRR, and a CTD in situ. In situ data were obtained in the northern Taiwan Strait during a winter cruise of 1998 from February 20th to March 8th, which suggested that warm streamer as indicated by 18℃ isotherm approached as north as 26°N. A series of AVHRR SST daily images covering the whole Taiwan Strait region, which were got on Feb.8th, Feb.25th and Mar.13th, respectively, confirmed that warm water mainly intruded into the Taiwan Strait from the southernmost tip of Taiwan, heading northeastward along the Penghu Channel. There were also some evidences hinting that warm water coming from the Kuroshio mainstream off Taiwan in the Pacific ocean, intermittently influenced the northern Taiwan Strait from the northernmost tip of Taiwan. This effect seemed to be weakening while the northeastward Kuroshio intrusion was strengthening from February to March. The mainstream of Min-Zhe Coastal Water was thus forced to go southwestward along the Mainland coast into the southern Taiwan Strait. This process probably heated Min-Zhe Coastal Water and led to the injection of nutrients into the southern Taiwan Strait, enabling unusual high winter Chla along the Mainland coast, especially in the southwestern Taiwan Strait, as shown by a single SeaWiFS Chla imagery on March 27th. Observation in situ from February to March also confirmed Chla enhancement in the northwestern Taiwan Strait. Chla content reached as high as ca. 5 mg/m+3, which were 4 times greater than that was observed in 1995. It was suspected that the unusual strong Kuroshio intrusion and the corresponded Chla enhancement in the Taiwan Strait during winter 1998 were probably related to the very strong tropic E1 Nino of 1997～1998.关键词：Taiwan Strait;Kuroshio;AVHRR;SeaWiFS
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发布时间：2021-06-10 - 摘要：The Internet GIS provides an open and normative environment for people to share the geographic information, the common resource of Human Kind. In particular, from 1998 the project of Digital Earth has been progressed forward. It is no doubt that the image of RS will play an important role in the progress of building the Digital Earth. But now there is a big gap between the bandwidth and the size of image, which has affected the application of RS image greatly. Therefore, in 1997 the International Standard Organization associated with Joint Photographic Experts Group began to set up a new coding system of still image-JPEG2000, which will solve this problem perfectly. This paper presents the archtecture of Web Gis application based on JPEG2000.关键词：Internet;JPEG;Web GIS;image
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发布时间：2021-06-10 - 摘要：Pearl River Estuary is an important region for South China, including Hong Kong and Macao. It has experienced tremendous environmental changes due to the fast social and economic development in Pearl River delta, especially in recent decade. It is rather difficult to realize the changes of water quality for this large complex estuary system over a long period by the traditional measurements. Remote sensing technology is used to monitor the evolution of marine water quality. The historic Landsat data over twenty-five years are applied to extract the changing information of ocean color. The results show an alarming fast trend of high turbid waters in Pearl River Estuary and Hong Kong coastal waters in these years. The algorithm of "Gradient Transition" is used to calibrate the resulting images to give quantitative analysis of turbid waters. Reasons for such deterioration are discussed in detail. A comparson method is proposed to process and analyze Landsat images to get feature of ocean color of Case 2 waters. The concept of multiple scatters is suggested for the study of turbid and shoal Case 2 waters near coastal zone.关键词：remote sensing monitor;Pearl River Estuary;Landsat image;change of coean color
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