Table of Content

25 August 2010, Volume 39 Issue 4

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学术论文

A New Hierarchical Spatial Index Based on Urban Morphology

, ,LI Guang-Qiang

2010, 39(4):  0-440. 

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Urban morphology is closely related with natural conditions, functional organization of land use and road network structure. Its basic skeleton is formed by axes of road and hydrographic network. Based on the principle of urban morphology, map space can be partitioned into four levels with its components being enclave, block, superblock and neighbourhood, which is obtained by some topographic features such as roads and hydrographic networks. Obviously, this way of partition is very natural and consistent with human cognition, and thus the basic components at each level are called natural grids. Indeed, the partition can effectively avoid such case that topographic features cross grids, which often occurs in the partition based on regular grids. A new kind of hierarchical spatial index method is further proposed based upon the natural grids, which can be combined into existing classification framework of spatial index. Several experiments are employed to prove that the redundancy of index recording in grid affects its efficiency greatly. In addition, the approaches of space partition and index building in this paper can be further used for map generalization and map updating, thus provide the basis for them in both theory and technology.

Velocity estimation on the colored noise properties of CORS network in China base on the CGCS2000 Frame

2010, 39(4):  0-440. 

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Abstract Based on the calculation of the coordinate time series of CORS network in China during the period from 1999 to 2009 base on the CGCS2000 frame, the paper proposes the adoption of spatial filtering algorithm based on principal component analysis (PCA) to extract the space-time characteristics of Common Mode Error (CME) in coordinate time series of CORS network in China base on the CGCS2000(Chinese geocentric 3D coordinate system). Secondly, the method of power spectrum analysis is applied to analyze the frequency spectrum characteristics of coordinate time series after spatial filtering and fitting, the noise characteristic of the residual coordinate time series are estimated quantitatively with the criterion of maximum likelihood estimation. Finally, it evaluates the annual speed evaluation and the actual accuracy of national CORS network under different color noise modes with the weight least squares method. The result shows the adoption of PCA method can promote the accuracy and reliability of CORS network base on the CGCS2000 frame, describes more precisely the movement characteristic of CORS network. The mean square error in the orientation of the north, the east and the height are reduced by 22%, 26% and 46% respectively after filtering. The white noise is not the main part of the noises in the coordinate time series of CORS network in China, while the white noise, flicker noise and random walk noise are the basic characteristics in the coordinate time series of CORS network, based on which can describe better the movement parameters of CORS network. The colored noise in CORS network is regular in the orientation of the horizon, the height, the North-South, the East-West. With the comparison of the consideration of the colored noise and the white noise, the change percentage of speed evaluation in CORS network is generally around 2%--10%, the error of the former is 2-6 times bigger than the latter.

An Algorithm of Dynamic Precise .Point Positioning Based on Modified Particle Filtering

2010, 39(4):  0-440. 

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Resource Locating and Selection for Spatial Image Streaming on P2P Network

2010, 39(4):  0-440. 

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Transmission of spatial data is one of the fundamental elements for virtual earth platform, mostly, it is built based on the centralized mode which is high cost or scaleless. As an beneficial complementarity and extension, Peer-to-Peer (P2P) mode applied on virtual earth platform's client could be a solution for scalable, robust and low cost virtual earth platform. This paper explores non-linear content access mode of spatial data on virtual earth, and then adopts grid-based peer group for resource locating on top of traditional P2P locating method. Further, we discuss peer selection mechanism to optimize the results of resource locating. Historical download speed records are combined to estimate the preference of peer so that high capacity and reliable peer can be chosen firstly. Two modes of our peer selection mechanism that are local optimal and non-equal probability have been tested through many simulative experiments. Results show the better effects with our peer selection mechanism comparing to random peer selection, and also tell that effectiveness of peer selection mechanism is related to application scenario such as peer number, file size and user behaviors.

Researches on User Action Monitoring and Data Mining in Adaptive Cartographic Visualization System

2010, 39(4):  0-440. 

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This paper established a preliminary run mechanism of adaptive cartographic visualization system, and particularly analyzed each module of system. Based on the above, the paper researched into the monitoring mechanism of user action, and used apriori association rules improved to the mining of user action database to adapt to ACViS. The experiment proved that the mining results have guiding meanings for ACViS designers and provide basis t for the renewal and modification of user model. The researches lay theoretical and technical foundations for follow-up research and development of adaptive cartographic visualization system.

A Model for Massive 3D Terrain Simplification Based on Data Block Partition and Quad-tree

2010, 39(4):  0-440. 

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By comparing several typical terrain simplification algorithms, local adaptive optimization simplified terrain model (LaostModel for short) was be established, which is based on quad-tree model and supports massive 3D terrain data. With LaostModel, many quad-trees are built by the mode which the massive terrain data is organized by multi-resolution blocked processing. Also, the LaostModel algorithm dynamically split or merges quad-tree data block according to viewpoint as well as the degree of roughness of local terrain, and the different level terrain is display by real-timely adjusting the different quad-tree nodes in a data block. In addition, LaostModel can solve a lot of other problems, such as, the crack problem caused by different resolution grid mosaic of terrain which is solved by breadth-first search algorithm, and the problem that how to determine which quad-tree node needs to be drawn which is solved by "bounding box" method, and so on. Testing of prototype system shows that the model fits satisfactorily and offers a useful reference for further studying.

Research on automatic matching of vector road networks based on global optimization

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2010, 39(4):  0-440. 

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Automated matching for road networks plays an important role in map registration, map update and change detection, and this paper carries out research on the problem of matching different levels of road network automatically. Because the great majority of the existing methods for matching road network are based on finding optimal solution locally, which will cause mismatch often occurs when homonymous road features differ greatly in their locations and there is 1:1 or 1:N corresponding relationship between them, so in order to solve such a problem, this paper constructs global optimization model of matching road network through analyzing locations, shape and topological structure of road junctions and road arcs, and this model not only considers local similarity between road nodes but also takes matching situations of their adjacent nodes into account. The optimal solution is found by using probability relaxation method, and matching relationship between road nodes and between road arcs can be obtained finally. In probability relaxation method, topological structure similarity between nodes is chosen as the initial probability, and shape similarity between road arcs is chosen as compatibility function. Many experiments indicate that our method can ensure that matching results agree with each other globally, and has a higher accuracy as a result, furthermore, as a strong constraint condition, global optimization can ensure that our method still gets a satisfactory result even when homonymous features differ greatly in their locations and there is 1:N matching relationship between roads, and avoids the difficult problem of setting proper weights to some degree.

Using Control Points’ 3D information to calibrate the Interferometric Parameters of Dual-antenna Airborne InSAR Systems

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2010, 39(4):  0-440. 

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Abstract: Sensitivity Equations method was adopted to research on the interferometric parameters calibration problem based on 3D reconstruction model for the Dual-antenna Airborne InSAR. Interferometric parameters calibration is the key of building higher precision Digital Elevation Model (DEM). A new 3D reconstruction model was proposed based on Madsen’s reconstruction algorithm after adopting spherical wave model and joining the attitude rolling. According to different sensitivity of each interferometric parameter with respect to 3D information, Ground Control Points(GCPs)’ 3D information was proposed to calibrate interferometric parameters that was different from common interferometric parameters calibration just using height information. The calibration experimentation was adopted a set of InSAR data, derived by the Airborne InSAR system researched independently by Institute Of Electronics, Chinese Academy Of Sciences. The experimental results show that this method is efficient.

A Feature-Based Dynamic Multi-scale Navigable Data Model

2010, 39(4):  0-440. 

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Dynamic multi-scale representation of the road network is required for navigation applications. In this paper, after depicting transportation features in thematic, spatial and temporal domains, a Feature-based Dynamic Multi-Scale Navigable data model (FDMSN) is devised with spatial, temporal and scale pictograms enabled UML class diagrams. In the model, firstly, topology and geometry of the road network are represented separately, where carriageways, which are constructed by linear referencing to underlying roads, are used as basics of the topologic network, and roads are used as basics of the geometric network. Secondly, these two networks are organized into hierarchical levels in terms of different criteria, that is, road class for the topologic network and display class for the geometric network. Thirdly, some different kinds of dynamic information, including traffic status data, traffic event data, statistical travel time data, etc., are integrated with the rock-bottom road network by link-node linear referencing systems and time-dependent thematic attributes. The experiment shows that the proposed model is effective enough to navigation applications by underpinning the corresponding data structure design and database implementation.

Space Feature-Based Reversible Watermarking for 2D-Vector Maps

²,SUN Jian-Guo²

2010, 39(4):  0-440. 

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Special applications of 2D-vector maps require extreme secrecy and vector data precision. The technique of reversible watermarking can strictly recover the original cover data, with the watermark accurately extracted at the same time. Therefore it is more suitable for digital copyrights protection of vector maps. This paper proposes a new space feature-based reversible watermarking for 2D-vector maps. Under the condition of keeping relative locations of feature points, this algorithm non-linear scrambles the location of feature points according to the predefined secret key to avoid the unauthorized users using of high-accuracy vector data, and then embeds watermark into the scrambled feature points, It can recover the original 2D-vector maps with the watermark extracted at the same time. The experimental results show that the proposed watermarking method is strictly reversible with preferable invisibility, it is a pragmatic algorithm used for 2D-vector map encryption and source traceability.

Variance-Covariance Component Estimation Based on the Equivalent Residuals

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2010, 39(4):  0-440. 

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The development of the variance-covariance component estimation (VCE) theory is firstly synoptically reviewed in this paper. Then the equivalent residuals are extracted by using orthogonal decomposition and the fundamental equations for VCE are established. Based on that the two profound and unresolvable problems for VCE theory, namely regional optimality and negative definition for estimated covariance matrix, are explored and the corresponding possible resolvable schemes and their complexity are analysed. Thirdly, we derive out the Helmert, Least squares and MINQUE VCE formulae based on the fundamental equations with the given initial values, and additionally we also prove their equivalence with the existing VCE formulae. The procedure of derivation is beneficial for us to understand the essence of VCE that all VCE formulae are identical. Finally, two examples are performed to verify the proposed viewpoints.

The Knowledge Modeling and Route Planning Based on Taxis’ Experience

2010, 39(4):  0-440. 

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It is believed that the routes chosen by taxi drivers are more reasonable and passable, and it is important to plan the route using the taxi drivers’ experience. This paper establishes the taxi drivers’ experience knowledge model based on analyzing the historical floating car data (FCD) and the taxi drivers’ route planning rules. The road network is classified into different experience levels, and a new route planning algorithm is proposed based on the road network of experience levels. In the end, this paper finishes 350 experiments with the road network and historical FCD of Wuhan, and compares the new algorithm with the traditional shortest path algorithm, the results show us that the routes planed by the taxi’ experience and knowledge model are more coherent and consistent, and that the traveling time can be reduced.

Research on the Simultaneous Solution Method for Satellite Gravity Data Analysis and Its Simulation

ZOU Xian-Cai ¹, ², ²,ZHANG Shou-Jian ²

2010, 39(4):  0-440. 

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Abstract: The research on the simultaneous solution method, which is used in the satellite gravity data processing, is a hot topic in the Chinese geodetic study. The main difficulty in the software development of the simultaneous solution method is how to deal with the GPS observation data. With the space-bone GPS tracking data as an example, the general principle and process for the software realization of simultaneous solution method are presented in this paper and the software has been developed. Using the simulated GPS tracking data spanning one month and the simultaneous solution method, a simulation aiming at the determination of the earth gravity model and the precise orbit are discussed. The results demonstrate the feasibility of the design method and the robustness of the software.

Decorrelation Filtering Methods for Gravity Field Recovery Based on Satellite Acceleration Data

2010, 39(4):  0-440. 

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n the acceleration approach for recovery of the Earth’s gravity field, the observation of satellite accelerations are derived from the satellite orbit data by numerical differentiation. However, the differentiation will rapidly amplify the high-frequency noise, which will degrade the accuracy of recovered gravity field model. Because the noise in the orbit-derived acceleration data is colored, whitening filters based on decorrelation technique are introduced to suppress the noise. Two whitening filters are constructed based on 3-points differential scheme and on ARMA model, respectively. As a test, simulated CHAMP orbit data with different type of noises are used to recover the gravity field model. The results demonstrate that the gravity field models recovered from the decorrelation filtering methods have higher accuracy than those from equal weight method, which validate the effectiveness of the decorrelation filtering methods.

EM algorithm based on Log-principal component transformation for remote sensing classification

2010, 39(4):  0-440. 

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Two nuisances will be encountered in classifying the multi-spectral data set using the EM algorithm. The first is the singularity of the variance–covariance matrix,which will lead to the failure of the computation; the second is the sensitivity to the initial values selected at random ,which will result in different final classification results. This paper suggests that the difference of classes is emphasized by logarithmizing the original data, and then apply the principal component transformation to the logarithmized data. The number of principal components for the EM algorithm is determined according to the contribution rate of more than 85% of all principal components. This not only removes the singularity but weakens the noise; The histogram of the first principal component of the logarithmized data reflects sufficiently the information of the class difference, from which the initial label for multi-dimensional EM algorithm can be efficiently determined, and the sensitivity of the initial value selected at random can be avoided. The experiment shows that the proposed strategy is better than the general EM algorithm and K-means.

Filtering of Airborn LiDAR Point Cloud Data Based on the Adaptive Mathematical Morphologybased on the adaptive mathematical Morphology

2010, 39(4):  0-440. 

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Mathematical morphology is widely used in the digital image processing. In this paper, the characteristics of traditional mathematical morphology algorithm are introduced and the shortages of the application of this theory in the LIDAR point clouds data classification and filtering are analyzed first. Then, on this basis, the corresponding morphological algorithms are efficiently improved and extended, and an adaptive filtering algorithm which is aimed at the characteristics of different terrain surfaces is proposed. Based on the “opening” operator of mathematical morphological, a method that a “bandwidth” parameter is added for the classification and filtering of LIDAR point clouds is proposed. Finally, experiments are processed using three groups of actual LIDAR point clouds data and the validity of the algorithm is validated by the different presentation forms from them.

Distribution of Navigation Value about Vertical Gradient and its Navigability Analysis

2010, 39(4):  0-440. 

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On the basis of the parallel Kalman Filter maching navigation priciple, a algorithm of navigation value for gravity vertical gradient aided inertial navigation system is proposed by using the least matching variance method. Combining the regional vertical gradient in the Western Pacific Ocean, the navigation value gridded in 2’×2’ in the area were determined. Through selecting five sailing courses in the different character region, simulation experiments were implemented and the statistic analysis for regional navigability was made. At last, the comparison and analysis of the navigability value, the matching rate and the positional error were given. The results show that, the navigation value of the vertical gradient can achieve good performance in the selected matching area and planned sailing courses, and the positional error is less than 2.0n mile if the navigability value is bigger than 14.0, moreover, the distribution of the corresponding area was showen.