Mineral identification and mineral mapping constitute one of the most successful field in the application of imaging spectra. This paper has classified the spectral identification techniques and identification models of minerals into two types: one is the spectral matching of rebuilt spectral data with standard spectra or measured spectra based on spectral similarity measure, while the other is the knowledge-based or intelligent methods based on mineralogical and mineral spectral knowledge. The classification of spectral matching, spectral similarity measure, whole spectral matching, partial spectral matching, sub-pixel identification, spectral un-mixing, end-member selection and dimensional reduction are analyzed and reviewed. The existent problems and research tendency in spectral mineral mapping are also discussed. The development of the identification technology by using whole spectral region from visible to middle and thermal infrared domain seems to be one of the most important trends in spectral mineral identification and mineral mapping.
Landslide RS survey includes the landslide recognition, the collection of the basic information, and the spatial analysis. With the Tiantaixiang landslide RS as an example, this paper illustrates the utilization of “special points” to determine the boundary and influence zone, movement characteristics and scale of the landslide. Landslide RS monitoring can be divided into direct RS monitoring and indirect RS monitoring. It is difficult to determine the exact time for large scale high velocity landslide movement, the scale of landslide movement is relatively small compared with the resolution of the satellite image, and as RS data are discontinuous and rather expensive, they are not quite suitable for RS direct landslide monitoring. Indirect monitoring means monitoring the environmental change caused by landslide activities. The Yigong landslide RS serves as another example to illustrate RS monitoring of lake change, ecological destruction and new landslides caused by landslide dam burst.
Landslide RS evaluation means the evaluation of the stability, the prediction of the future activities, the detection of the affecting factors and the evaluation of the regional hazards caused by landslide development. Tiantaixiang and Qianjiangpin landslides and regional landslides in the Three Gorge area all serve as examples.
Oasis is a special ecological landscape of the arid land. Nevertheless, the oasis study had not been regarded as an important research field until the end of the 19th century. In the past two decades, a certain progress has been made in the study of oases, and a series of achievements have been attained with the development of RS, GIS and some other new land monitoring technologies. Based on recent research literature available, this paper deals with five important problems, i.e., the formation and development of oasis, the oasis water resources, the oasis LUCC, the oasis agriculture and the ecological environment protection of oasis. Based on detailed analyses, the authors point out the existent problems and put forward some opinions on the development of RS technology for the study of oases in China.
The conventional repeat-pass differential SAR Interferometry (D-InSAR) was proved to be a remarkable potential technology for mapping surface deformation. However, a full operational capability has not yet been achieved due to phase decorrelation and atmospheric disturbances. A stacking differential interferograms strategy is presented for surface deformation rate derivation in this paper. In this algorithm, the pixels that preserve a good coherence level in the whole interferograms stack are identified to generate the triangulation network with Delaunay criteria. The Minimum Cost Flow (MCF) algorithm is used for phase unwrapping of individual interferogram. The unwrapped phase series of each point is used to estimate the linear deformation rate, and the standard deviation of the estimates of the linear subsidence rate is calculated to indicate the nonlinear subsidence of the pixel. The algorithm was tested with 9 scenes ASAR data acquired from 2004 to 2005 to derive the linear subsidence rate of Langfang City.
This paper describes in brief the development of the MPI (Microwave Polarization Index) technology and makes a derivation for MPI according to the radiance transfer equation. The authors collected MODIS LAI/NDVI matching to AMSR-E MPI by using the longitude/latitude as the control condition. The analysis indicates that there exists an exponent relationship between MPI and LAI/NDVI. The better the relationship, the lower the frequency. This paper also deals with the microwave polarization index in the application field.
With the help of multispectral data collected by Landsat-7 and the in situ data collection and on the basis of the preprocessing of the remote sensing data and the spectral and correlation analysis of data, the authors made an analysis of the boric anhydride content of the Zhabuye salt lake, which has a high concentration of boric anhydride and complex components, as evidenced by the results obtained by such methods as ratio enhancement, principal components and density slice. It is found that there exists spatial distribution regularity governing the boric anhydride content of the Zhabuye salt lake.
This paper studied the altered minerals under the geological and geographical conditions of the Sebei Gas Field in Qaidam Basin, and analyzed the relationship of the spectral character between the known gas field and the background district in the study area with the help of the illustration of Hyperion Imaginary and the satellite hyperspectral remote sensing data. On such a basis, 932.64~1 346.25 nm and 2 002.06~2 385.5 nm were confirmed as the optimal spectral ranges for distinguishing the information of background and that of target. Then the oil and gas special distribution information was extracted by the SAM (Spectral Angle Mapper) method. As a result, some promising gas fields such as the Taijnar gas-bearing structure were recognized, thus providing an effective method and approach to oil and gas exploration with the satellite hyperspectral remote sensing technology.
This paper deals with a new method for remote sensing data recovery, which is based on the Digital Elevation Model (DEM). In this technique, ground topography acts as the key factor, and random effects of satellite remote sensing are ignored. First, a DEM is created according to the digital contour lines from the basic geographic data. Then, through combining the ground real data with DEM and corrected remote sensing data, the slope & aspect analysis of pixel in remote sensing data is performed, thus building up a model which shows the relationship between the DEM and the remote sensing data so as to characterize the action mechanism of the topography on the remote sensing data by mathematical statistics. Finally, the remote sensing information recovery is conducted for each pixel in remote sensing data. With this method, an excellent information recovery result has been achieved. The technique can also eliminate or reduce the influence of topography on remote sensing data. Therefore, it enhances the practical application of remote sensing techniques under the complex topographic conditions of mountain areas.
The leaf reflectance spectra (R), lg(1/R), standard first derivative reflectance spectra (FD) and absorption band depths following the continuum removal and normalization (BN) of Changyou 1 and Wujing 15 were measured and calculated. The relationship between different spectral performances and rice leaf chlorophyll contents was analyzed. Then the statistic equations between leaf chlorophyll contents and different spectral performances were established, and a comparison was made between them. The best estimator selection was also discussed. The results show that the correlation obtained by the equation established from FD is the best, and the lg (1/R) spectra can improve the retrieval of chlorophyll contents with remote sensing. The multiple correlation coefficients (R2) between estimated and observed rice leaf chlorophyll contents of the two varieties were 0.641 and 0.818 respectively.
Based on an analysis of the present precision correction process, the authors adopted four measures, i.e., function modularization, alternative control automatization, large amounts of calculation parallelization and exchange files standardization, to enhance the performance of precision correction processing in the satellite image ground preprocessing system, which enable us to make precision corrections in large quantities. In addition, these approaches can also be used to solve other problems of mass remote sensing image processing.
This paper deduces a simple formula for computing the incidence radiant flux density. Based on the definition of albedo, the authors put forward a new method of surface albedo inverse model. The TM data of the Poyang Lake were used to make a test, and the average relative error was only 4.91%. The method is easy to utilize, and it only needs spectral data of two different kinds of land covers. In addition, it doesn’t need the albedo computation of narrow wavebands. The method proves to be a good means for inversion of surface albedo.
Following the inoculation of stripe rust disease of different levels in the winter wheat field, the authors measured the stripe rust disease severity and winter wheat canopy reflectance at different growth stages. PLS (Partial Least Square) was adopted to build a regression model for disease severity inversion from canopy reflectance. The results indicate that the inversion accuracy of PLS is higher than that of the method proposed in reference［4］, which used PRI (Photochemical Reflectance Index) to predict disease severity. Regression coefficients of PLS were investigated to obtain useful knowledge. It has been found that the first derivatives on the two sides of the chlorophyll absorption valley (505~550 nm，640~670 nm，680~700 nm) are most important in determining disease severity. Diseased winter wheat has higher absolute values of first derivatives in the three spectral regions.
Landscape of the ancient Lijiang town was restored by using VirtualGIS technology in this paper，and the scientificalness of city site selection was analyzed too. When selecting the city site of the ancient Lijiang town in Ming Dynasty, people used the geomantic omen method, and took into account physiognomic, geologic, hydrologic and climate conditions. The geographic superiority of the ancient Lijiang town was very obvious. The site selection can serve as a classical model for reference in city building.
During 2003~2005, the authors completed two projects, namely, ‘Synthetic Archaeological Studies with Remote Sensing and Geophysics Survey’ of China high-tech (863) program and‘Archaeological Studies to the Mausoleum of Zhou Dynasty’by China History Museum. With old airphotos (1956), the authors made some discoveries: ① On the east side of the Mausoleum of the Emperor Qinshihuang (259–210 BC) there were remarkable small surface morphology anomalies over the terra-cotta army and the zigzag-shaped pit. The anomalies and the pit were found and excavated in 1974 and 1976; ② There existed a tumulus group on Shengheyuan (plateau form) in Chang’an County of Shanxi province and a rectangular relic of Qin cemetery wall (2300 years ago).
The Bojianghaizi ring structure was discovered by interpreting and analyzing the ETM remote sensing images in the Ordos basin. Field investigation was also made to confirm the discovery. Results of detailed studies indicate that it is special structure related to gas and oil formation. It is considered that this ring structure played an important role in sand type uranium mineralization of northern Ordos basin.
The remote sensing images of 1989, 1995 and 2004 were interpreted to get the land use information of the study area with BPNN. Based on the location theory and the geographic analytical method, this paper studied the time and spatial evolution model of the land use caused by the subsiding land and the relationship between the transformation of the subsiding land and the location effects. The results show that the evolution of the land use types assumed an obvious ring structure, and that the variation speed and extent in the central area were greater than those in the outer area. In the central area, different kinds of land were transformed mainly to the subsiding land. The transformation in the intermediate area took place mainly among the cultivated land, garden land, wood-land, subsiding land and construction land. The periphery area mainly assumed transformation between the construction land and the garden land.
This paper puts forward a classification method for high resolution remotely sensed images based on multi-feature objects, analyzes its advantages in comparison with the traditional pixel-based means which completely depend on spectral information. A case study related to the classification method is described, and the result shows that the new technique based on multi-feature objects is more efficient than the pixels-based methods.
A new method is proposed in this paper for the mapping of the water image, the flood dynamic image and the flood hazard image using the 250m, 2-band MODIS data. Its application in the Poyang lake area indicates that the method can preserve the image spatial resolution and help us to quickly recognize the water and flood. This method provides a rapid, simple and easy approach to the dynamic monitoring and mapping of flood hazard.
An investigation of the wetland from Bohai Gulf to Laizhou Bay by GIS and Landsat-7 shows that there are many types of wetlands, such as natural wetlands and artificial wetlands. This area has a wetland area of 15 060.29 km2. Natural wetlands have an area of about 10 071.31 km2, which make up about 67% of wetlands while artificial wetlands occupy about 4 988.98 km2, which constitute about 33% of wetlands in the study area.
In this study, the authors selected Jinghong City along the Meigong River and Pingbian County along the Honghe River as the study areas, where the land use classifications under the same spatial scale were compared. The results were verified with the help of ground real data and analyzed by Kappa statistics. The results show that: (1) It is essential for Yunnan Province to establish a hierarchy classification scheme based on geomorphology characteristics; (2) The effect of different classification schemes varies with spatial scales, e.g., on the small scale, the classification based on analyzing statistics of spectral reflectance yields acceptable accuracies. On the larger scale, however, due to the influence of landform, the expert system or inductive classification may improve the mapping accuracy.
The remote sensing data of the Shanghai base data platform constitute the basic data that contain the urban spatial information, and they have been widely used in different departments of the government. This paper puts forward the main idea concerning the construction of remote sensing data of the Shanghai base data platform. Having been constructed through several links, the remote sensing data of the Shanghai base data platform are issued in three ways for different kinds of users. Practice has demonstrated that the remote sensing data of the Shanghai base platform occupy a key basic position in the spatial information data chain.