Based on a brief description of three sorts of geodesic remote sensing satellites, this paper has summed up the requirements for spatial resolution of remote sensing images in the major application fields of China.

Land Use Detailed Survey (LUDS) is a process for acquiring detailed information about types, distribution, quantity, application status and tenure of land on large scales according to The Chinese Technical Order of Land Use Status Survey. LUDS is characterized by rigorous land use classifications, strict precision indices, on-the-spot survey and land tenure survey. Nevertheless, the traditional methods for LUDS are based on handwork, and are hence time-wasting and need lots of manpower; In addition, the survey processes have cockamamie programs and can easily produce errors. With the rapid progress of RS, GPS and GIS, the conditions for acquiring land use information are much better than before. This paper briefly describes the concerted methods of 3S in LUDS and evaluates the precision improvement. It also points out some troubles in 3S application.

Land desertification investigation of the agriculture and graziery mixed area in Duolun region of Inner Mongolia was carried out twice within five years by means of TM image monitoring. The classification system of land desertification combining land desertification with land use can effectively delaminate and separate various sorts of land desertification by adopting a set of ratio combinations according to the vegetation indices. The first survey revealed that land desertification became increasingly serious due to excessive cultivation and grazing in Duolun County, and the second survey shows that the land desertification management has been effective and the trend of deterioration has been restrained. Remote sensing monitoring has been playing an active part in preventing and controlling desertification of that area.

This paper has discussed the similarities and differences between remote sensing and remote sensinggeological mapping in the rocky desertification area and drawn a mathematical analytical conclusion that the determination of the rocky desertification area is equivalent to the determination of the area that satisfies the condition D_R∈ D_C∩ D_V. On such a basis, two schemes for extracting information from remote sensing images of rocky desertification are advanced. One is to extract the information of remote sensing images of the rocky desertification directly from brightness (or gray level) of every pixel based on the frequency characteristics of limestone rocks and the heat characteristic parameters, in which the relevant method used is called pixel analysis method or direct recognition method. The other is to extract the whole graphical information of the outcrop distribution area of limestone rocks indirectly through logical correlation operation between image areas D_C and D_V based on the model of vegetation image frequency and topology, in which the relevant method used is called graphic analysis method or indirect recognition method. The optimum scheme for pseudo-color composition with the Axis of TM6 as the central waveband has been determined through two times of 30×2 tests of pixel analysis method for images in the test area. Through comprehensive interpretation, it is concluded that the expansion of the rocky desertification area in Du'an is related to excessive human activities. This achievement is attributed to the utilization of this scheme to TM image processing in Du'an County in 1991 and 1998.

Land use dynamic index is one of main models for depicting the change rate of land use types. When it depicts the change rate of the single land use type, it uses the net value of the area change of the single land use type. In fact, the net change results from bilateral dynamic change of the land use type. The change rate of land use use shown by the singe type land use dynamic degree thus calculated has already offset part of the bilateral change. On such a basis, a bilateral change dynamic degree model is put forward in this paper. In addition, the advantages of the model in expressing more land use information are also dealt with on the basis of investigation into the Jiangxia District of Wuhan City.

There has been remarkable change in land use types of North China in recent years. The authors completed the dynamic investigation of land use, and analyzed land use dynamic change from 1995 to 2000 based on RS and GIS. The results reveal that the land used for urban and rural residence has been increasing rapidly, especially in the countryside, and the cultivated land has been reduced and increasingly changed into construction land. It is also shown that the forest land, the virgin soil land and the diversity of land use have been decreasing obviously, indicating that the human activities have become stronger and stronger, which exert adverse impacts on the environment.

Remote sensing technique has been used in geological study of Deerbugan forest and marshland area, Inner Mongolia. Regional tectonic and metallogenic regularity has been studied in detail on the basis of geological analysis of suitable remote sensing images and, as a result, some noble metal (Au, Ag ) and nonferrous metal ore-forming prospect areas have been delineated.

Based on the topographic characteristics of the Nansha Sea Area, this paper has analyzed geologicaland zoological features of island reefs from the growth state of different coral reefs and coral shoals by means of TM image, studied substantial ingredients and growth grades of underwater reefs and beaches according to TM image features, put forward classification method for island reefs shallower than 30m in water depth from TM image, investigated and verified shapes and distribution of islands, reefs,beaches and shoals in the Nansha Islands and perfected classification of island reefs in the Nansha Islands.

This paper deals with a method for analyzing the best route on the basis of raster data. Utilizing "Dijikstra" algorithm and "node/link" model, the method first calculates the least weight distance from every cell to the resource cell (cells), with the weight distance figured out by the cells of 8-adjacent directions, then calculates the back-link values, and finally finds the best route according to the accumulative weight distance raster and back-link raster. With an example, this paper describes the method and steps for finding a best route based on the GRID module of Arc/Info software. This paper also points out the advantages and disadvantages of this method, and puts forward the train of thought for improving it.

There are many approaches to the extraction of dynamic change information from remote sensing imagery. However, their operations are very cumbersome, and their efficiency is not so ideal. Double-edge seems to be a good solution. Double edge refers to the boundaries between the neighboring objects or parts in remote sensing image, with the width of its boundary being two pixels, and it can be described by two raster lines. It helps to interpret the objects in remote sensing image by the region of double-edge and to understand the features of dynamic changes by the colors of the double-edge. The procedure for interpretation of dynamic changes based on double-edge is simple and convenient, and the technique contributes to cutting down the work load and reducing the interpretation errors. This paper presents the principles and application of this approach, and makes the information extraction test for land use changes from remote sensing image.

Classification is the crux of the automatic classification of remote sensing data. Brightness of aware sort is the classification norm of distance classification. Distance classification compares brightness between aware sort and unknown pixels. Angle of spectral line is the classification norm of degree classification. Degree classification compares angle of spectral line between aware sort and unknown pixels. Using both sorts of classification, the authors classify the same remote sensing image and make a comparison between them.

This paper describes the principle of TM imagery adjustment technique. Through adjustment-processing and error-analyzing of TM imagery data obtained from Nansha Islands,we can get fairly accurate positioning information by using TM imagery and corresponding control data.

This paper analyzed quantitatively the relationship of mud content in water and spectral reflectance of water, then discussed the factors affecting water reflectance. Through comparing the regression analyses of the water reflectance and the mud content in every band from 350nm to 2 500nm (totally 2 151 bands), the optimum band was found. The method will be of some help to calculating mud content of sea water, river water or flood by means of hyperspectral remote sensing image, and also to estimating the amount of soil erosion.

This paper deals with present conditions and development trends of GIS and OA, points out the existent problems in integrating GIS and OA system, and puts forward a method based on component technology for realizing the seamless designing of GIS and OA. In the end, the paper advances a new model of GIS and OA combination.

The Single frequency Global Positioning System receiver widely used in land and resources investigation is affected adversely by different error roots in positioning, and hence the analysis of the main error roots can help us to avoid or reduce the adverse influence and improve the accuracy of positioning.

The disappearance of the ancient Loulan city in Xinjiang has been regarded as a riddle. Through the application of satellite remote sensing technology and the interpretation of the distribution characteristics of the old river in Loulan area from TM image, the authors have found that there are two landslide sites and barrier lakes located in the upper reaches of the river. Based on this discovery, it is thought that the abandoning and final disappearance of Loulan might be attributed to landslides which cut off its water source and broke off its water supply.