Based on related papers carried in various academic journals of China since 1990s, the authors have summarized in this paper the advances in the application and researches of hyperspectral imaging remote sensing in such fields as geology, oceanography, agriculture, atmosphere and environment. For the purpose of reflecting the most recent advances in the application and researches of hyperspectral imaging remote sensing, this paper also gives a brief account of the development of this technology abroad.
This paper has reviewed the development of remote sensed imagery interpretation, analyzed the present research condition and characteristics of various imagery interpretation methods and, on such a basis, forecasted the development trend of remote sensed imagery automatic interpretation in future.
Cloud-free composition of MODIS data is successfully realized on the basis of improved composite algorithms developed in C++ language, and 16-day MODIS composite images covering China and its surrounding regions are generated. It can be concluded from the above result that the improved composite algorithms are feasible and effective under various conditions.
A new data fusion method is proposed in this paper for improving CBERS-1 IRMSS images based on CCD image. After precise co-registration, each pixel in a low spatial resolution image is correspondent with a group of sub-pixels in a high spatial resolution image. For each pixel in the low spatial resolution image, the average value of its co-registered sub-pixel brightness values in the high spatial resolution image was calculated. The difference between the pixel brightness value in the low resolution image and its sub-pixels average value was added to every sub-pixel value in the high resolution image. This procedure was applied to each pixel to produce a data fusion image. The fusion image had more spatial details than the low resolution image, and its spectral information was similar to that of the low resolution image. The test result indicates that the new data fusion method is an improved fusion technique not only in enhancing the spatial details of IRMSS image but also in keeping the fidelity of the image spectral properties. Different from other data fusion methods, the new method can perform data fusion for an individual low resolution image and realize the enhancement of the thermal infrared band 6 of Landsat based on the other higher resolution band image. Being a very simple and practical technique, it is potentially useful in enhancing the spatial details and preserving the spectral fidelity of the low resolution images.
As one of the most detailed LULC digital maps now available to public, China 1km grid multi-layer LULC digital map has been published in a format containing 25 layers, in which every layer represents a specific area percentage of a certain LULC category in each grid (1 km×1 km) area of the whole territory of China. Such kind of digital map is very useful in rapid investigation of national land resource and environmental component distribution, but may not be practical in distributed hydrological modeling studies. For the purpose of overcoming this knotty problem, an improved method is proposed in this paper, which takes the best use of the original LULC information from China 1km grid multi-layer LULC digital map but makes some modifications to meet the needs of hydrological studies in practice. A single layer gridded LULC digital map is thus generated based on the principle of area-dominant and spatial smoothing techniques in which main LULC classes are well kept and most of the spatial distribution attributes are enhanced. As an example, the map generated for Yingluoxia basin of Heihe area is discussed on the basis of its application to a distributed hydrological simulation. The result demonstrates its practicality in meeting the needs of hydrological modeling purposes.
SIR-C is the first space-borne imaging radar system with multi-wavelength and quad-polarization developed by the joint effort of the USA, Italy and Germany. Polarization SAR measures the scattering matrix of each pixel on ground and synthesizes the image at given orientation and ellipticity angle, including linear and elliptical polarization. It has many advantages over single or multi-polarization SAR in such aspects as detecting objects, identifying targets and extracting texture. Nevertheless, the relatively high correlation of the synthesized polarized images and the complexness of scattering of objects often lead to wrong interpretation of the images and poor accuracy of classification. Based on SIR-C data of Hetian prefecture in Xinjiang, the authors used the target decomposition theory to decompose the data into three non-relevant scattering components. The result shows that the decomposed three scattering components reflect the correct scattering feature. The authors then combined them with polarimetric synthesized SAR power image to classify the experimental area by using MLC or neural net. The classification result shows that the method can effectively extract the information of land cover, achieve relatively good classification accuracy of ground objects and improve the capability of SAR for monitoring the land use and cover.
This paper describes the application of RS and GIS to the comprehensive evaluation in pipe-route selection between Jingbian and Zhengzhou, the most difficult section in the project of transmitting gases from western China to eastern China. Considering the characteristics of this area, the authors established a comprehensive evaluation system of the pipe route with RS as the basic information source. The system includes twelve data layers such as pipe length, traffic conditions, crossed barrier and terrain. Taking GIS as the technological support, the authors carried out spatial analysis and statistical analysis for each topic. By means of Analytic Hierarchy Process (AHP) combined with experts' knowledge, administrative level analysis was used for all element weight defining and sequence arrangement. All routes were objectively evaluated in detail. The best route has been selected, which provides the decision basis for route-selection.
Remote sensing geological features of Mid-northern Qinghai-Tibet plateau show that four NE-trending Quaternary depressions exist in the area between Lancangjiang-Wenquan and the southern margin of eastern Kunlun-Animaqing lithospheric faults. The graben geomorphic characteristics of Northern Xiqiangtang and Changjiang Riverhead depressions are obvious, whereas the Huanghe Riverhead and Ruoergai depressions are of relatively low development degree. However, they are products of the east-west geomorphic extensive deformation, and the dynamic background of the deformation is the same as that of the continental tectonic deformation of Qinghai-Tibet plateau. Studies further show that the deformation of these depressions not only has the same dynamic significance as the NS-trending rifts in mid-southern Qinghai-Tibet plateau but also serve as important factors affecting the ecological system of that region.
Based on the data related to the bided land of Nanjing in 1998, this paper has constructed the data set of the land price samples, compiled contour maps illustrating resident land price and commercial land price by means of the software"MapInfo", and analyzed and compared these contour maps. In order to analyze the relations between the variation of Nanjing land prices and the principal location factors, this paper has formulated relevant models in statistical software"SPSS" and interpreted the results.
Using such new techniques as remote sensing and GIS, the authors obtained the newest statistical data on the saline alkalized land conditions of 1980s and middle and late 1990s in western Jilin Province. Based on spatial analysis, it is concluded that the area of the saline alkalized land has been uninterruptedly expanded in recent 20 a, accompanied by the deterioration of the land quality, and that the development of salinization and alkalization is characterized by phase and time sequential variations. Finally, some countermeasures for prevention and treatment of saline alkalized land are put forward in the light of economic management and ecological engineering.
Nanping area of Fujian Province was selected as a plot to analyze the quality of CCD data. The test was conducted by comparing band 2, 3, 4 of CBERS-02 with the corresponding band 2, 3, 4 of Landsat 7 ETM+ in the light of grey level analysis, correlative analysis, spectral characteristics and classification precision of forest information. The feasibility of applying CBERS02-CCD data to forest resources monitoring is discussed.
Based on detailed studies of quite a few NOAA/AVHRR images, it is found that the image of channel 3 could be used to extract not only the information of high temperature objects but the information of normal temperature objects as well, and that in many cases it is better than the image of channel 4 in the information extraction. In this paper the authors have also made a concrete analysis and probed into the causes of such a phenomenon.
The authors have built in this paper the spatial information mapping model of historical land data based on a discussion of its integration and interoperability. This is an important basic study in land information field. Here the authors' academic views are put forward to attract more attention to this research field.
WebGIS, namely Web-based GIS, is produced by combining GIS with Web technology. With the help of the rapid and convenient operation of the web and the specific analytical function of GIS, it enables people to utilize the information and data widely distributed on the internet in a more efficient way. Exemplified by the atlas query information system of Changchun City, this paper demonstrates the performance of WebGIS.
