摘要:At present E-commerce system tends to become more complex, and traditional system designing methods can not fufil the need of E-commerce system, thus requiring an effective methodas solution. With this concern, this paper introduces some concepts of component technology, then brings forward the new connotation and basic features of component technology through the analysis of its technological character. This paper finally discusses the application of component technology to E-commerce system.
摘要:Direction is a common spatial concept that is used in our daily life. It is frequently used as a selection condition in spatial queries. As a result, it is important for spatial databases to provide a mechanism for modeling and processing direction queries and reasoning. Depending on the direction relation matrix, an inverted direction relation matrix and the concept of direction pre- dominance are proposed to improve the detection of direction relation between objects. Direction predicates of spatial systems are also extended. These techniques can improve the veracity of direction queries and reasoning. Experiments show excellent efficiency and performance in view of direction queries.
摘要:The basic principle of interval arithmetic and the basic algorithm of the interval Newton methods are introduced.The prototype algorithm can not find any zero in an interval that has zero sometimes,that is,it is instable.So the prototype relaxation procedure is improved in this paper.Additionally,an immediate test of the existence of a solution following branch-and-bound is proposed,which avoids unwanted computations in those intervals that have no solution.The numerical results demonstrat that the improved interval Newton method is superior to prototype algorithm in terms of solution quality,stability and convergent speed.
摘要:This paper puts forward a new conception:model warehouse,analyzes the reason why model warehouse appears and introduces the characteristics and architecture of model warehouse.Last,this paper points out that model warehouse is an important part of WebGIS.
摘要:This paper puts forword 11 cartographic generalization operator models and introduces their mathematical definitions,and thus a precise mathematical form and quantitative description has been given to these formerly limited qualitative concepts.The meaning of mathematical definition of operators for cartographic generalization and the application prospect in computer-aided cartography (CAC) is stated.
摘要:Contributions are welcomed on one of the following subjects or in related areas: ·GIS ·Geodynamic ·Physical geo-surveying ·GPS ·Geo-surveying ·Engineering
摘要:This paper first establishes the prior globe dynamical model by geophysics,which is a solid earth elastic deformation model.Then,the parameters of the globe dynamic model can be obtained by inverting the geodetic data.The inverse method can be used in seismology and geology,and to make earthquake prediction.
摘要:At present,there exist two methods used to recover the bathymetry from altimeter data,i.e.the deterministic method and the stochastic method.In this paper,the principles of the two methods are introduced first.Then according to the theory of least-square collocation,a modified statistical model for recovering bathymetry from altimeter data is proposed.The new model has been used for computing the ocean depth in the South China Sea from altimeter-derived gravity anomalies.Finally the predicted depths are compared with the ship-borne depth.It shows that they agree with each other very well.
摘要:This paper calculates the parameters of image position and orientation,proposes a mathematical model and adopts a new method with three steps of transformations based on parallel ray projection.Every step of the model is strict,and the map function of each transformation is the first order polynomials and other simple function.The final calculation of the parameters is for the linear equations with good status.As a result,the problem of the relativity of image parameter calculation is solved completely.Some experiments are carried out.
摘要:Rough set is a new approach to uncertainties in spatial analysis.In this paper,rough set symbols are simplified and standardized in terms of rough interpretation and specialized indication.Rough spatial entities and their topological relationships are also proposed in rough space,thus a universal intersected equation is developed,and rough membership function is further extended with the gray scale in our case study.We complete three works.First,a set of simplified rough symbols is advanced on the basis of existing rough symbols.Second,rough spatial entity is put forward to study the real world as it is,without forcing uncertainties into crisp set.Third,rough spatial topological relationships are studied by using rough matrix and their figures.The relationships are divided into three types,crisp entity and crisp entity (CC),rough entity and crisp entity (RC),and rough entity and rough entity (RR).A universal intersected equation is further proposed.Finally,the maximum and minimum maps of river thematic classification are generated via rough membership function and rough relationships in our case study.
摘要:This paper first develops the approaches to determine the geopotential of the local mean sea level,and then investigates the offset of the 1985 vertical datum surface defined by the mean sea level of Yellow Sea at the Dagang Tide Gauge in Qingdao city using the developed approaches and GPS/leveling data.It shows that the geopotential of the local mean sea level at the tide gauge is equal to 62 636 853.5±0.2 m2*s-2 and that the 1985 vertical datum surface is 24.6±5.4 cm above the geoid realized by the geopotential W0=62 636 856.0±0.5 m2*s-2.
摘要:This paper presents a data processing strategy for GPS kinematic positioning by using a GPS active network to model the GPS errors in double difference observable.Firstly,the double difference residuals are estimated between the reference stations in the active network.Then the errors at a user station are predicted as the network corrections to user measurements,based on the location of the user.Finally conventional kinematic positioning algorithms can be applied to determine the position of the user station.As an example,continuous 24-hour GPS data in March 2001 has been processed by this method.It clearly demonstrates that,after applying these corrections to a user within the network,both the success rate for ambiguity resolution and the positioning accuracy have been significantly improved.
摘要:This paper describes the use of the Arc/Info and ArcView GIS tools to estimate soil erosion with Universal Soil Loss Equation (USLE).Calculations are be done by using capabilities available.This study start with a digital elevation model (DEM) of Shaanxi,which was created by digitizing contour and spot heights from the topographic map on 1∶250 000 scale and grid themes for the USLE K and C factors.It is note worthy that USLE K can be obtained by adding the K factor as an attribute to a soil theme's table.The C can be obtained from tables or using the information about land use and management given by USLE program.A land use theme can be used to add the C factors as an attribute field.The purpose of this study is to establish spatial information of soil erosion using USLE and GIS and discuss the analysis of the soil erosion and slope failures in GIS and formulate the possible framework.
摘要:This paper advances a new simplified formula for estimating variance components ,sums up the basic law to calculate the weights of observed values and a circulation method using the increaments of weights when estimating the variance components of traverse nets,advances the charicteristic roots method to estimate the variance components of traveres nets and presents a practical method to make two real and symmetric matrices two diagonal ones.
摘要:Automatic generalization of geographic information is the core of multi-scale representation of spatial data,but the scale-dependent generalization methods are far from abundant because of its extreme complicacy.This paper puts forward a new consistency model about scale-dependent representations of relief based on wavelet analysis,and discusses the thresholds in the model so as to acquire the continual representations of relief with different details between scales.The model not only meets the need of automatic generalization but also is scale-dependent completely.Some practical examples are given.
摘要:This paper focuses on the study of ocean bathymetric inversion from satellite altimeter data by using FFT technique.In this study,the free-air gravity anomalies over the South China Sea are determined by the satellite altimeter data of GEOSAT,ERS-1,ERS-2 and T/P.And the 2.5′×2.5′ bathymetry model in South China Sea is calculated from the gravity anomalies with the inversion model given.After the analysis of the inversion and the comparison between the results,some conclusions can be drawn.
摘要:This paper focuses on the integration and data transformation between GPS and totalstation.It emphasizes on the way to transfer the WGS84 Cartesian coordinates to the local two-dimensional plane coordinates and the orthometric height GPS receiver,totalstation,radio,notebook computer and the corresponding software work together to form a new surveying system,the super-totalstation positioning system(SPS) and a new surveying model for terrestrial surveying.With the help of this system,the positions of detail points can be measured.
摘要:This paper investigates the mathematic features of non-linear models and discusses the processing way of non-linear factors which contributes to the non-linearity of a nonlinear model. On the basis of the error definition, this paper puts forward a new adjustment criterion, SGPE.Last, this paper investigates the solution of a non-linear regression model in the non-linear model space and makes the comparison between the estimated values in non-linear model space and those in linear model space.
摘要:The theoretical framework of visual simulation in virtual reality is discussed. The new concept of visual image space is supposed. On the basis of visual image space, in visual perceptive sense, VR is considered as a spatial simulation. The objective of the spatial simulation is to transform physical space to visual image space.Last, the prototype system, surveying & mapping virtual Reality (SMVR),is developed, and the space simulation above is realized. By use of SMVR,the real 3D representation, 3D visual analysis, virtual plan and designs can be implemented.
摘要:This paper presents the contemporary motion and active deformation of South America plate and relative motion of Nazca-South America plate using space geodetic data. The South America plate is moving at average 14.5 mm/a with an azimuth of 15.2° and shrinking in the west-east at 10. 9 mm/a. The geodetic deformations of sites with respect to the South America plate are in quite good agreement with the estimated deformations from NNR-NUVEL1A, but the deformation of the western South America regions is very large.
摘要:Positional error of line segments is usually described by using "g-band", however, its band width is in relation to the confidence level choice. In fact, given different confidence levels, a series of concentric bands can be obtained. To overcome the effect of confidence level on the error indicator, by introducing the union entropy theory, we propose an entropy error ellipse index of point, then extend it to line segment and polygon,and establish an entropy error band of line segment and an entropy error donut of polygon. The research shows that the entropy error index can be determined uniquely and is not influenced by confidence level, and that they are suitable for positional uncertainty of planar geometry features.
摘要:On the basis of stereo image analysis, the change detection of man-made objects in urban areas is introduced. Information of the height of man-made objects can be applied to reinforce their change detection. By comparison between the new and old DSMs, the changed regions are extracted. However, our aim is to detect changes of man-made objects in urban area and further in the potential areas by the means of line-feature matching and gradient direction histogram. The experiments based on the aerial images from Japan have proven that the algorithm is correct and efficient.
摘要:On the basis of the principles of simple random sampling, the statistical model of rate of disfigurement (RD) is put forward and described in detail. According to the definition of simple random sampling for the attribute data in GIS, the mean and variance of the RD are deduced as the characteristic value of the statistical model in order to explain the feasibility of the accuracy measurement of the attribute data in GIS by using the RD. Moreover, on the basis of the mean and variance of the RD, the quality assessment method for attribute data of vector maps during the data collecting is discussed. The RD spread graph is also drawn to see whether the quality of the attribute data is under control. The RD model can synthetically judge the quality of attribute data, which is different from other measurement coefficients that only discuss accuracy of classification.
摘要:Automatic extraction of road and linear structure from remote sensing images is a very important problem. This paper analyses several existing methods of the automatic road and linear structure extraction by using some multi-spectral remote sensing images acquired from different spatial resolutions, districts and road characteristics. Their advantages and disadvantages have been generalized.
摘要:This paper develops a wide-band multi-spectral space for color representation with Aitken PCA algorithm. This novel mathematical space using the broad-band spectra matching method aims at improving the accuracy of color representation as well as reducing costs for processing and storing multi-spectral images. The results show that the space can present our experimental original spectral spaces (i. e. Munsell color matt and DIN-6164 color chips) with high efficiency, and that the spanning space with three eigenvectors can present the original space at more than 98%CSCR, and when 5 eigenvectors are used it can cover almost the whole original spaces.