This paper analyzes the situation of current agricultural pollution problem in China and examines the applicability of remote sensing technology to agricultural pollution monitoring on the regional scale. Specific emphasis is placed on the application of remote sensing to water pollution monitoring, soil contamination evaluation, variation of crop polluting and air pollution from agricultural activities. The integration of remote sensing with geographic information system techniques is also examined with the purpose of establishing agricultural pollution management systems for the spatial modeling of agricultural pollutants cycling among the spheres of farmland soil, water bodies and atmosphere and the controlling of the pollutant movement in these spheres. Therefore, remote sensing of agricultural pollution is a front academic investigation field both in remote sensing and in agricultural pollution. Nevertheless, not enough importance has yet been attached to this research field in China. It is hence very necessary to promote the academic investigation of this front field in that such investigation is not only the requirement of remote sensing science but also the demand of agricultural pollution control in China.
Thermal infrared remote sensing is one of the focuses in remote sensing investigations all over the world, and the retrieving of land surface temperature is an important research field. This paper has analyzed the difficulties in the inversion process and summed up several methods for estimating ground absolute emissivity. Three inversion methods and their main merits and shortcomings, their application fields and conditions are described, and the future development trends as well as the key points in the inversion of land surface temperature are also dealt with in the end of this paper.
The extraction of road from the high resolution remote sensing image remains an open question in spite of the fact that lots of efforts have been made in this area. This paper describes the road feature, road model and the basic idea, analyses the methods for road extraction. The thought and the plans of further research on this subject are also presented.
Texture is the key character of remote sensing image. In this paper, the image texture was extracted by means of semivariogram. On such a basis, this study adopted the back propagation artificial neural network method to make classification by combining spectral feature with many sort of textures. The classification results were then compared with the results obtained by the maximum likelihood method. The results of the study have proved that the application of combined spectral features and textural measures based on the geostatistics and NN theory to the classification of the remote sensing image may improve the accuracy of image classification.
The spectral behavior of altered minerals leads to the spectral characteristics of altered rocks. Using the multivariate data analysis of typical rocks, the relation between the components of altered minerals and spectral data can be estimated qualitatively and quantitatively, and hence a model for extracting remote sensing information of mineralization and alteration can be established. Using the spectral data obtained in field and chemical analysis data of typical rock (ore) samples in a gold polymetallic mineralization belt in Qinghai, the authors studied the model for extraction of remote sensing information of mineralization and alteration on the basis of multivariate data analysis, and established a linear regression model of ratio combination, whose application effect is better than that of the single ratio method.
Based on the theory of water remote sensing, this paper has reached the conclusion that TM3 band is the optimum band in investigating the depth of the salt lake by means of correlation analysis. A quantitative analysis was also conducted on the depth of the highly concentrated Zabuye Salt Lake, and the result obtained reveals the spatial variation regularity of the water depth of this lake. On such a basis, the remote sensing mechanism and the remote sensing model of the water depth of the highly concentrated salt lake are built in the paper.
Topographic analysis has been widely used in the study of landscape evolution and surface process, and the researches in this field have become more and more quantitative. Local topographic relief, which is defined as the difference between local maximum elevation and local base level, is one of the key methods in topographic analysis. Based on a spatial analysis of the SRTM-DEM, this paper puts forward two methods for the acquisition of local topographic relief, i.e., Swath Profile and Threshold Value. The quantitative analysis of the erosion within a typical area of the Loess Plateau has been preliminarily realized by extending the Threshold Value method.
Based on the multi-temporal remote sensing image data, the authors have analyzed the land use change of axial urbanization growth on the southwestern margin of Shanghai in the past 10a or so, investigated and obtained the variation quantity of all kinds of land use, the features of spatial distribution of land use change, and the intensity of urbanization growth. The density of developed areas in the mature urbanized district is also calculated. By comparing the density between the developed areas in the mature urbanized district and every test block, the authors have formulated “the process index of the urbanization”, and carried out the portrayal of the urbanized spatial process.
A method of snow covered ground simulation using the first-order radioactive transfer model is described in this paper. In this method, three parts of the echo are taken into account, i.e., top surface scattering, volume scattering and subsurface scattering. A new surface scattering model——AIEM, instead of the IEM model, is used to deal with the surface scattering problem. Finally, the improved method is verified using the measured data of 1995 from the University of Michigan.
With its 36 bands, Terra/MODIS has been widely used in atmosphere, water and land field monitoring. This paper deals with the operational method and technological process of sandstorm monitoring. It is pointed out that the addition of the analytical means based on two band bounds limits can be used as the operational method and that the technological process includes data preprocessing, information selection, grade classification, and comprehensive analysis. On the basis of the technological process and the method, sandstorm monitoring from April 8 to 11 in 2003 were carried out. The comparison between the result from NOAA-16 and that from FY-1C reveals its good effect. This research enriches the means of sandstorm monitoring and provides another data source and method for such monitoring, and hence the result obtained has operational potential.
The MMP (Minimum Maximum Points) filter algorithm is a highly-efficient filter algorithm for the spatial data in the object-relational spatial database. The description and the application result analysis of the MMP algorithm demonstrate the advantages of the MMP algorithm in the retrieval of mass volume of spatial data, i.e., the speed of the MMP algorithm is at least scores of times higher than that of the function operation.
The direct measurement of exterior orientations using the integrated IMU/DGPS system proves to be an effective means. Experiments show that the accurate performance of direct orientation measurement is sufficient for forming orthophotos and small or medium scale maps. Aimed at solving the problems existent in the IMU/DGPS orientation module, this paper deals with the integrated IMU/DGPS system and the elements of IMU/DGPS-based photogrammetry and, on such a basis, emphatically analyzes the overall system calibration.
By means of digital image processing techniques of data integration, image fusion, principal component analysis and directional filter with landsat-7 ETM+ image under the image processing platform of ENVI 4.0 software, the authors successfully enhanced the information of faults in the remote sensing survey of fault structures along Motuo highway in Tibet. With technologies of structure analysis based on geological knowledge, information extraction and thematic mapping supported by ArcGIS 8.2 software, faults in Namjagbarwa region were recognized and interpreted completely, and their features and distribution along the highway route were detected. The results have provided enough scientific evidence for selecting the highway route and evaluating engineering geological conditions.
Cloud cover is a very common noise in remote sensing images. The removal of the effects of cloud cover and the acquisition of real information from the covered area constitute an important task in image recognition and classification. In this paper, the authors have summarized the methods for removing the effects of cloud cover. A comparison of the results between homomorphic filter processing and Kriging interpolation in the same study area shows that the latter method is better than the former.
The new round renewing of land-use maps is being gradually carried out. The original land-use data have problems of format disunity and hard sharing. The development of modern techniques makes it possible to apply multi-source data to renewing land-use data quickly, accurately and efficiently. This paper introduces a method for renewing the land-use map by using high resolution remote-sensing data, land-use data, inquisitional data and GPS data.
Remotely sensed data based land use/cover classification, especially in mountainous areas, is a difficult problem that has long drawn attentions among researchers. This paper presents a synthetic approach using C4.5 algorithm to automatically derive classification knowledge with the purpose of constructing a model of decision tree for the final classification of the image. Statistical relationships of the land-use pattern with DEM were analyzed through spatial analysis function of GIS to provide extra knowledge for the post classification processes, which improves the precision of final classification by enhancing the characteristics of the trial zones in the image. According to a classification experiment on the rugged terrain over the upstream of Hanjiang River Basin where the land use/cover ground survey data are available, the proposed approach is far superior to the traditional maximum likelihood classification method.
The research on the land use/cover change is one of the frontiers and hot spots in the global change researches. Based on remote sensing and GIS technology, the authors analyzed the spatial-temporal characteristics of land use/cover change in the border areas of Yunnan province by using MSS and TM data acquired in 1976 and 2004 respectively. The analytical result of remote sensing shows that the surface features are mainly forests and naked rocks, and subordinately farmland and waters. Remarkable changes include four types, namely, forestland, waters, farmland and naked land. Forestland and waters have decreased by 9.72% and 1.84% respectively, while farmland and naked land increased by 5.74% and 4.44% in the past thirty years. The problems of ecological environment and resources and the driving factors resulting from land use /cover change in the border areas of Yunnan province are analyzed
The classification of remote sensing images constitutes the basis of LUCC research. The land use/cover information of Minhang was obtained by means of the multi-stage classification approach. The verification of the classification results indicates that the accuracy of the classification is 85%. The results of classification are satisfactory.
As an important part of Location-Based Service (LBS), the moving objects information management platform plays a very important role in information management of such city moving objects as vehicles. This paper first analyzes characteristics and existing problems of the current moving objects information management platform, and then gives a technical analysis of its key technologies and designs the implementation method. With practical examples of vehicle management, it is shown that the framework of moving objects information management presented by this paper is feasible.