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Objective: Global navigation satellite system (GNSS) Continuous Operating Reference Station (CORS) System can maintain a accurate, 3D, geocentric and dynamic reference coordinate frame in the corresponding area, can provide positioning and navigation service. It can also serve for the meteorology, geodynamics, earthquake monitoring and Location Based services (LBS) etc in the same area. Until now, our country can’t provide a facing National CORS System serving for every profession and trade, and the national sharing platform of CORS System resources has not been established. So this paper discusses some valuable insight how to construct the National CORS System in China. Method: Constructing goal、Service object、CORS distribution、CORS geographic、geology and communication environment and other factors, are major considerations for the Constructing the National CORS System. Moreover, constructing GNSS CORS is more specific, mainly from four aspects, namely site-selection、civil construction、security measures and equipment-selection for consideration. Outcome: The project of the Constructing Global navigation satellite system (GNSS) Continuous Operating Reference Station (CORS) System in china is put forward, and is discussed from goal、principle、project and other for construction. Some meaning thought how to construct the National CORS System is submitted Conclusion: The Global navigation satellite system (GNSS) Continuous Operating Reference Station (CORS) System in china is the lack of a unified planning and design in the national level. So far, the national CORS system serving all walks of life has not been provided, and the national sharing platform of CORS System resources has not been established The primary mission of the Global navigation satellite system (GNSS) Continuous Operating Reference Station (CORS) System in china is as follows: using data set of GNSS and receiving, transport, process, integration, transmit information and the corresponding services, providing real-time dynamic space location service up to sub-meter to meter level, providing high precision、three dimensional signal point coordinate using post-precision positing technology up to centimeter to millimetre level, these will help ensure maintain the unified、high precision and up to date of the three dimensional geocentric coordinate frame serving for the entire land and sea of our country. The National CORS system of china by combining with information of《 international GNSS services(IGS) 》, can provide satellite orbital data、clock data、coordinate and its movement speed of international and home CORS, troposphere and ionosphere information and parameters of antenna phase center stations over CORS sites, etc. Based on customer’s requirement, the National CORS system of china can also provide remote data processing custom service、RTK and precise point positioning service, etc; and provide weather forecast、wireless communication obstacle forecast、earthquake monitoring and other up to date information services. Open data services platform is provided from the National CORS system of china, and will widely service in all walks of life, and will also service for economy, national defense and society development in our country.

The rigorous geometric model based on the collinearity equations is the basic model for object positioning of high resolution remotely sensed imagery. The location precision is strongly relevant to the ephemeris and attitude data. However, the quality of attitude data acquired by modern stellar camera is still difficult to satisfy the requirement of direct location. In this paper a calibration model of constant angular error is introduced to enhance attitude precision by few ground control points (CCP) . The calibration model was tested on SPOT-5 and QuickBird imageries and both have proved its practicality and efliciency. An object positioning accuracy of 4 pixels in planimetry was achieved after calibrating and correcting the constant angular error by using single GCP.

Semantic sharing is the key issue to interoperability in the community of geographic information. By exemplifying inland hydrological categorization in the domain of the fundamental geographic information in China, a discussion is made on the ambiguous semantics of the normative definitions of categories in some specifications. Ontology is regarded as an effective means to OVercome semantic barrier in the domain of geographic information. A paradigm of formal semantic analyses of geographic information is put forward in this paper, in terms of the formal ontology. With conceptualization of a category, attributes of a category are used for expressing its semantics. By examining the given hydrological categories, the formal semantics of each geographic concept is explicitly specified by a set of the defined ontological properties ayer its attributes.

In large scale terrain roaning systems, the terrain visualization components are usually running on the localhost and terrain datasets are stored in the remote server.The server should guarantee the certain response delay and realize the teal-time tendering of huge-scale terrain when the number of user is limited. However. as the number of clients is quickly increasing, the server performance will no rapidly to satisfy the client real-time tendering requirement. Peer-to-peer (P2P) technologies can efficiently reduce the bandwidth consumption of the server by the means of utilizing the client nodes' resource. The paper combines the C/S and peer-to-peer into 2 new data transmission mode for large terrain data transmission. First, it gives a new model for data transmission and new' structure for client node. Then it presents the management of peers and the look-up of terrain blocks in the new mode. Also it presents a kind of optimal algorithm for terrain block scheduling. The optimal algorithm can improve the terrain data transmitting speed and be adapted to the network change. Fault-tolerance and security are also considered in the paper. We build a prototype system and compare the new mechanism with traditional unicast mode. Experimental results have shown that the new mechanism can make the server's bad lighter than the old mode in the case of equal number of user requests and improve greatly the response time of the terrain block request.

Purpose: In order to describe the dynamic earth Scientifically, especially with the development and improvement of the space geodetic techniques such as global positioning systems, a lot of countries in the world are updating and improving their geodetic coordinate system and corresponding coordinate frame. Geocentric coordinate systems and their framework are gradually replacing the traditional non-geocentric geodetic coordinate system and their framework. Our country also established the Chinese modern geodetic datum, in order to promote the use of geocentric coordinate system 2000, the definition and geodetic fundamental constants of Chinese geocentric 3D coordinate system(CGCS2000)is introduced, which will be employed since July 1,2008 and the corresponding coordinate frame with CGCS 2000 is reviewed. Method: The current frame is consisted by 2000 National GPS geodetic network and its adjustment results combined with the national astronomical geodetic network, the customers may be satisfied with frame in recent years.. The influences on the current existing Chinese maps caused by the change of the coordinate systems, such as the changes of latitude, longitude, Gauss plane coordinates of the surface points and their projection on the map, as well as the variation of the orientation and the length of the lines between the points on the map (including map outlines) are discussed, and the fundamental way to deal with it is introduced. This paper introduces the definition of CGCS2000 and its geodetic fundamental constants and the establishment of China’s geocentric three-dimensional coordinates frame, including the design and establishment of China’s national GNSS CORS system and national high-precision geodetic control network, and the impact on the existing maps are researched by using CGCS2000. Result: The latitude, longitude, Gauss plane coordinates of the surface points and their projection on the map, as well as the variation of the orientation and the length of the lines between the points on the map (including map outlines) will be changed. Conclusion: If Xi'an 80 coordinate system is transformed into CGCS 2000, ①the changes of latitude and longitude of points are -1.6"~+0.7" and -6.4"~ -3.0" respectively. The absolute average of latitude and longitude are 0.57 "and 4.4" respectively. ②the change rates of Gauss plane coordinates X and Y values of point are -48.6m~+22.7m and -115.7m~-75.7m respectively. The absolute average of Gauss plane coordinates X and Y values are 16.31m and 106.9m respectively. So, due to the change of coordinates system, the coordinate of point of the maps (1:50000 or larger scale) will have 1cm or less displacement. The displacements of different points in the same map are different, but the differences are within mapping accuracy. So when the coordinate system changes, we only give the contour points to the new coordinate annotation for the existing maps, and then the maps can be viewed as with the new coordinate system coordinate. ③the length and orientation changes of the lines (including map border line) for the map (all the scales) in our country are all within mapping accuracy, so they can be negligible.

SPOT-5 HRS/HRG imagery is one of the main data sources for the project of West China Topographic Mapping at 1:50 000 Scale. New advanced technologies, such as the block-adjustment with sparse GCPs and mapping with high-resolution satellite imagery, are very necessary to the project. In this paper, we present an approach for block-adjustment based on Rational Function Model (RFM) with sparse GCPs by using satellite images. To test the proposed approach, it has been applied to SPOT-5 HRS images over 2 test-fields, one is in Baoji City, Shaanxi, China, and another covers eastern part of Tibet Plateau, China. All test-fields are with variable terrain geomorphologic type and several tens of GCPs and check points measured by DGPS. The block adjustment results show that with small number of GCPs we can achieve 5~9 m in planimetric and 2~3 m in height direction. The accuracy satisfies the requirements of Chinese Surveying and Mapping regulations for l = 50 000 scale topographic maps.

1.1 Objective Map databases are irreplaceable national treasure of immense importance. Their currency referring to its consistency with respect to the real world plays a critical role in its value and applications. The continuous updating of map databases at 1:50,000 scales is a massive and difficult task for larger countries of the size of more than several million’s kilometer squares. This paper presents the research and technological development to support the national map updating at 1:50,000 scales in China, including the development of updating models and methods, production tools and systems for large-scale and rapid updating, as well as the design and implementation of the continuous updating workflow. 1.2 Methodology The updating of map databases is different than its original creation, and a number of new problems should be solved, such as change detection using latest multi-source data, incremental object revision and relation amendment. The methodology of this paper consists of the following three parts: 1) Examine the four key aspects of map database updating and develop basic updating models/methods, such as currentness-oriented integration of multi-resource data, completeness-based incremental change detection in the context of existing datasets, consistency-aware processing of updated data sets, and user-friendly propagation and services of updates. 2) Design and develop specific software tools and packages to support the large-scale updating production with high resolution imagery and large-scale data generalization, such as map generalization, GIS-supported change interpretation from imagery, DEM interpolation, image matching-based orthophoto generation, data control at different levels. 3) Design a national 1:50,000 databases updating strategy and its production workflow, including a full coverage updating pattern characterized by all element topographic data modeling, change detection in all related areas, and whole process data quality controlling, a series of technical production specifications, and a network of updating production units in different geographic places in the country. 1.3 Results A group of updating models and technical methods were proposed after a systematic investigation of the key problems arising from the continuous updating of national 1:50,000 map databases. A set of specific software tools and packages was further developed to support large area updating. With these innovative methodologies and tools, a total of 19,150 map sheets at 1:50,000 scales had been updated and such a massive task was completed in an acceptable time frame, i.e., from 2060-2010. The data currency of national 1:50,000 map databases has been raised from 20-30 years to 5 years! 1.4 Conclusion A modern state requires accurate up to date maps and keeping them up to date on a regular basis is a massive task for a country the size of China. National Geomatics Center of China (NGCC) has solved this problem by using the latest data sources and developing new techniques. The methodologies developed in this paper are suited to regular updating in other rapidly developing nations and establish a model which can be followed in similar circumstances throughout the world.

Aimed at the problems of cartography and geographic information engineering and increasing demands of national and military infomationization construction, the paper proposes six hotspots on the research of cartography and geographic information engineering for the future on the foundation of analyzing the development track of cartology, which are heterogeneous geospatial data assimilation, transferring from emphasizing geography infor-mation gaining to user-oriented geographic information deep processing, web or grid geographic information service. intelligent spatial data generalization. integration of GIS and VGE. cartography and geographic information engineering theory system with multi-mode(Map,.GlS..VGE) spatial-temporal integrated cognition as the core. And discusses the necessity ,existing groundwork and research contents on studying these hotspots.

Levels of detail (LOD) is the key feature of 3D GIS. Aiming at the critical issues of LOD models organization, this paper presents an extended dynamic 3D R-tree structure concerned with LODs, which improves existing node-choosing and node-splitting sub-algorithms. In the node-choosing process, a globally-optimising approach is adopted which is first bottom-up then top-down, and that an improved clustering algorithm based on k-medoids is applied to the node-splitting process. This method makes more even node size, more regular node shape, and less node overlap. Furthermore, a method of integrating R-tree and LOD is put forward based on such kind of good R-tree structure. In order to verify the validity of this method , the simulated experimental analysis results approve that this approach improves 3D query performance greatly relative to existing ones and succeeds in integrating LOD models, which denotes good application prospect and practical value.

The ZiYuan-3 (ZY-3) surveying satellite is the first civilian high-resolution stereo mapping satellite of China. Its objective is oriented to plot the 1:50,000 and 1:25,000 topographic maps. Comparing with foreign commercial mapping satellite imagery, the establishment of our own imaging geometry model is the core technical problem for different products and various applications of ZY-3 surveying satellite. This paper analyses the key problem on precision geometry processing based on the overall design, and proposes the ZY-3 Surveying satellite imaging geometry model with the technology of virtual CCD line-array imaging. In addition, this paper utilizes the first orbit imagery of ZY-3 satellite with coverage of the region of Dalian, and produces forward, backward and nadir cameras calibration products. Different ground control points are selected for the block adjustment experiment, and the Digital Surface Model (DSM), Digital Ortho Map (DOM) are generated. The accuracy is validated by check points. It can be seen from the experiment that the planar and vertical accuracy are better than 3 meters and 2 meters, respectively. The experiment demonstrates the effectiveness of ZY-3 surveying satellite imaging geometry model

The status and development background on the research of the local geoid of the world in the recent 20 years is reviewed in this paper. An updated 2′×2′ digital quasi-geoid model (CNGG201;) for the National Height Datum 1985 of China is computed by using Stokes-Helmert method. More than one million land gravity measurements, 7.5″×7.5″ digital elevation data from SRTM, and 649 order B GPS/leveling data are used in the computation of CNGG2011. The average accuracy ofCNGG2011 is±0.13m in China, and±0.07m and ±0.14m in eastern and western China, respectively. The average accuracy in each province is±0.06 m, and they are±0.05 m and±0.11 m in the East and the West of China respectively, and it is±0. 22 m in the Tibet area. The relationship between the gravimetric geoid and the GPS/leveling is also discussed and some strategies for geoid refinement in the future are also proposed for National Height Datum in China.

A kind of single-frequency precise point positioning (PPP) algorithm based on the raw observations is presented in this paper. By this algorithm, the ionospheric delays were corrected efficiently by means of adding the ionospheric delay prior information and the virtual observation equations with the spatial and temporal constraints, and they were estimated as the unknown parameters simultaneously with other positioning parameters. Then, a dataset of 178 International GNSS Service (IGS) stations at day 72 in 2012 was used to evaluate the convergence speed, the positioning accuracy and the accuracy of the retrieved ionospheric VTEC. The series of results have shown that the convergence speed and stability of the new algorithm are much better than the traditional PPP algorithm, and the positioning accuracy of about 2-3 cm and 2-3 dm can be achieved respectively for static and kinematic positioning with the single-frequency observations' daily solution. The average bias of ionospheric total electron content retrieved by the single-frequency PPP and dual-frequency PPP is less than 5 TECU. So the ionospheric total electron content can be used as a kind of auxiliary products in GPS positioning.

Having the advantage of 360° imaging and rotation invariance, panoramic camera has gradually been used in mobile mapping systems(MMS). Calibration is an essential requirement to make sure that MMS can get high quality geo-information. This paper presents a way to address the extrinsic calibration for vehicle-based MMS composed of panoramic camera and Position and Orientation System (POS). Firstly, control points in the natural scene are set up, whose spatial coordinates are measured with high precision. Secondly, a panoramic spherical model is constructed and panoramic image can be projected to this model by means of spherical reverse transformation projection. Then, localize and select the control points in 3D spherical panoramic view but not in panoramic distorted image directly, the spherical coordinates of control points in panoramic image are gotten. After points correspondence is established, make use of direct geo-reference positioning equation and coordinate transformation, the translation and rotation parameters of panoramic camera relative to POS are computed. Experiments are conducted separately in space city calibration site located in Beijing and the Binhai New Area in Tianjin using our approach. Test results are listed as follows. When the GPS signal are of good quality, absolute positioning mean square error of a point is 10.3 cm in two-dimension plane and 16.5 cm in height direction; Otherwise, it is 35.4 cm in two-dimension plane and 54.8 cm in height direction. The max relative error of distance measurement is about 5 cm over a short distance (distance

This paper presents a new method of loess shoulder line extraction with openness and threshold segmentation. Openness is an angular measurement of the relationship between surface relief and horizontal distance which can be derived from DEM. As it has the outstanding ability of expressing the positive and negative terrain characteristics and the attribute of "analysis-scale flexibility", in this study, we developed the idea of loess shoulder line extraction based on the difference of positive and negative openness images and threshould segmentation. Firstly, we calculated the positive and negative openness of our study area based on DEM. Then, a difference image was generated by the subtraction of positive and negative openness images. Afer that, it was processed by a threshold segmentation method, and we analyzed some important spatial distribution characteristics of positive and negative terrain in study area. Finally, we extracted the shoulder lines semi-automatically by an edge-detection method which came from the concept of morphology. Our study area locates in Louchuan, Shaanxi province, a typical hilly gully region in northwstern China. Considering the effect of the local window size on analysis accuracy and the match of the fitness surface and DEM terrain surface, we chose a 5 m×5 m high-resolution DEM of Luochuan which was purchased from Shaanxi Administration of Surveying, Mapping and Geoinformation. The result manifested that our method enhanced and guaranteed the accuracy ofthe basic geomorphological characters of study area.

Address is a spatial location encoding method of individual geographical area. In China, address planning is relatively backward due to the rapid development of the city, resulting in the presence of large number of non-standard address. The space constrain relationship of standard address model is analyzed in this paper and a new method of standard address extraction based on the tree model is proposed, which regards topological relationship as consistent criteria of space constraints. With this method, standard address can be extracted and errors can be excluded from non-standard address. Results indicate that higher math rate can be obtained with this method.

Packing spatial data into blocks and processing of global impact of local operations are two important tasks for spatial index to support bulk operations. In this paper, we present a new spatial index called Pattern-tree for bulk operations with spatial distribution pattern analysis. For packing objects into blocks, a new spatial data partitioning method based on the detection of the spatial distribution pattern was presented. This paper introduces a novel spatial index construction algorithm that combines of top-down and bottom-up methods; For processing of local update operations and its global impact, this paper introduces a new algorithm based on change analysis of the spatial distribution pattern. Empirical results demonstrate that performance improvements are achieved in practice in the case of spatial index construction and windows query compared with STLT, GBI and SCB.

The estimation criteria for solving parameters in zero-differenced GPS positioning is that observations obey Gaussian white noise distribution. But a number of pioneering studies point out that the white noise would be damaged by satellites errors, propagation errors, station environment errors and so on. Meanwhile, un-modeling errors also have adverse effects. These errors not only undermine the assumption estimation criteria, and some non-white noises are likely to be absorbed by state parameters. In result, the accuracy of estimates is influenced. This paper regards white noise, colored noise and un-modeling errors as ZD stochastic model of GPS. Then the Allan variance method is proposed to analyze the posteriori residuals which can represent the Stochastic characteristics of GPS data. Noise component and parameters are mainly investigated. The result shows GPS noise behaves as WN plus GM. The phase and pseudorange WN is 2.392 mm and 0.936 m respectively, GM process noise is 4.450 mm/√s and 0.833 m/√s respectively, correlation time is 52.074 s and 14.737 s respectively. It is found that the phase GM component is associated with satellite, but the rest is associated with station. A number of analysis indicate that the ZD stochastic model characteristics of GPS obeys non-Gaussian white noise distribution and is to be refined.

Uncertainty often exists in the process of obtaining measurement data, which affects the reliability of parameter estimation. This paper establishes a new adjustment model in which uncertainty is incorporated into the function model as a parameter. A new adjustment criterion and its iterative algorithm are given based on uncertainty propagation law in the residual error, in which the maximum possible uncertainty is minimized. This paper also analyzes, with examples, the different adjustment criteria and features of optimal solutions about the least-squares adjustment, the uncertainty adjustment and total least-squares adjustment. Existing error theory is extended with new observational data processing method about uncertainty.

The energy conservation approach has been adopted to exploit GOCE orbit information in earlier GOCE time-wise and space-wise gravity field models which are two kinds of official ESA products, but the accuracy of long-wavelength gravity signal is low. Gravity field recovery with GOCE satellite data is an ill-posed problem and the precision of zonal coefficients is low due to the polar gaps, which needs be processed by regularization technique. This paper analyzes the accuracy of existing approaches for gravity field recovery in processing GOCE data and the selection of optimal regularization techniques and parameters. Several gravity field models were recovered based on GOCE precise orbits of 92-days from 2009-11-01 to 2010-01-31 with the energy conservation approach, short-arc integral approach and average acceleration approach. These approaches do not require any initial values of unknown parameters and reference gravity models. Besides, the Tikhonov regularization technique was applied to tackle the ill-posed problem. The results show that the highest accuracy of the model is recovered by the average acceleration approach, the lowest accuracy is the energy conservation approach, and the accuracy of short-arc integral approach is slightly worse than average acceleration approach. Therefore, such methods as the average acceleration approach or short-arc integral approach should be recommended to be applied when processing the GOCE orbit data. Gravity field models can effectively recovered by GOCE orbit data with the order and degree 120 when orbit and gradiometer data are combined to processes in the future. Kaula regularization and second-order Tikhonov (SOT) are superior to other regularization techniques in dealing with ill-posed problem of GOCE, and the corresponding optimal regularization parameters of both techniques are consistent. However, the effects of polar gaps could not be completely inhibited by regularization technique; it should be combined with other data, such as GRACE satellite data, to get the desired results.

Additional nonlinear baseline length constraint is often used for GNSS dynamic relative positioning, but the LAMBDA method can only deal with linear constraint model. So, it is necessary to linearize and approximate nonlinear constraint conditions. Linearized approximate constraint usually increases the success rate of fixing integer ambiguity, but for the ultra-short baseline, the opposite results may be derived. When will the linearized approximate baseline length constraint can improve the success rate of fixing ambiguity? This article attempts to answer these questions. Firstly, the float solution's maximum influence value formula is derived when using linearized approximate baseline length constraint, based on GNSS relative positioning model; Secondly, a discriminant condition is given to determine whether baseline length constraint can be linear approximation. When the condition is met, the influence can be ignored, linearized approximate baseline length constraint can improve the accuracy of float solution and increase the success rate of fixing ambiguity,on the contrast, the influence may not be ignored, linear approximation will result in a biased float solution and the ambiguity cannot be fixed correctly; At last, the foregoing conclusions are verified with some numerical example in this paper.

The inversion of variations of terrestrial water storage by the earth time-variable gravity filed model makes a great contribution to global climate change, however, the spherical harmonics of time-variable gravity field have correlation problem and significant errors in high orders and degrees, and so optimal filtering method is needed to solve this problem. In this article, a new filter was devised named‘non-isotropic combination filter’, and showed a better performance. The basic idea of the new filter is to apply the Gaussian filter and the RMS filter to low-degree and high-degree harmonic coefficients separately. In this paper, we first analyze the error characteristics of the latest GRACE RL05 series variable gravity field model, compare the validity and precision with Gaussian filter, improved Gaussian filter, RMS filter, DDK filter, the non-isotropic combination filter and verified them with the model. It shows that the mean square error of the non-isotropic combination filter and model is the least. Based on above analysis, we find that the non-isotropic combination filter can suppress the noises in high-degrees and high-orders, eliminate the N-S striping errors, lower signal leakage errors, improve the ratio of signal-to-noise more effectively compared with the previous filters.

A global optimization and whole registration algorithm of multi-view 3D laser point cloud is presented. Detailed derivation of global optimization adjustment model of multi-view laser point cloud is showed in this paper. This algorithm can handle disordered and scattered multi-view 3D laser point cloud, at the same time optimal transformation parameters can be obtained. Practical 3D laser point cloud data are exemplified for the feasibility and effectiveness of proposed methods.

To address the misclassification issue on buildings extraction based on Freeman decomposition method, a novel improved three-component decomposition model is proposed in this paper. By combining the selective de-orientation derived from the circular polarization correlation coefficient method with the generalized volume scattering model, it can accurately characterize the scattering characteristics of surface features. On this basis, the complex Wishart iterative classification is introduced to develop a new method of buildings extraction. An E-SAR L band polarimetric SAR image was used to verify the effectiveness of this modified algorithm. The experiment result shows it could perform better in distinguishing between oblique buildings and forest, and consequently improve the accuracy of buildings extraction.

Geotagged personal datas, which are released by laptop, tablet PC or mobile device,contain personal data such as text, photos, video information and geographic position information. In this paper, we propose a new visualization method—the topological map of personal geotagged data (simply, the topological map) and provide the design and implementation of the core algorithm for the method. In order to evaluate the effectiveness of the method, we conduct a usability test for "a text list", "a thematic map" and "a topological map" and use analysis of variance(ANOVA) to deal with test data. The results show that the three kinds of user interfaces have statistically significant difference in terms of efficiency in finding personal geotagged data, and there are not significant difference between a text list and a topological map, while the latter is slightly faster than the former, however, both are significantly better than a thematic map.

With the development of mobile and Web technologies, there has been an increasing number of map-based mushups which display different kinds of POI data in volunteered geographic information. Due to the lack of suitable mechanisms for multi-scale visualization, the display of the POI data often result in the icon clustering problem with icons touching and overlapping each other. This paper introduces a multi-scale visualization method for urban facility POI data by combing the classic methods of generalization and on-line environment. Firstly, we organize the POI data into hierarchical structure by preprocessing in the server-side; the POI features then will be obtained based on the display scale in the client-side and the displacement operation will be executed to resolve the local icon conflicts. Experiments show that this approach can not only achieve the requirements of real-time online, but also can get better multi-scale representation of POI data.

Cartography and map are all very important to topography and geography. Experts and scholars in different historical periods have different views of the attributes of cartography and the value of map. The paper discussed the science attribute, technology attribute and engineering attribute of cartography, summarized the value of map from science, society, jurisprudence and military aspects. It will be helpful to understand the basic attributes of cartography and the value of map, promote the sustained and healthy development of them.

Based on a detailed analysis of the Slepian function, the advantages and disadvantages of the application of the Slepian function in computing lunar local gravity model, local power spectrum combined with the CEGM02 model and local admittance and correlation based on CEGM02, SGM150j, LP150Q and GRAIL660 were analyzed in this paper. It turns out that the local orthogonal Slepian function shows obvious advantages in modeling lunar local gravity field. In the application of power spectrum, the method of Slepian model shows a much wider, credible and reliable bandwidth but brings greater uncertainty in high degrees with the abnormal signal on the cap edge. On the contrary, the local power spectrum curve of Slepian window reflects the relationship between local gravity and the whole moon, but the spectral curve shows a narrow reliable bandwidth and significant errors in low degrees. Local admittance and correlation of four gravity models shows small difference in low orders but obvious difference as the orders get higher.

Automatic cloud detection for optical satellite remote sensing images is a significant step in the production system of satellite products. For the browse images cataloged by ZY-3 satellite, the tree discriminate structure is adopted to carry out cloud detection. The image was divided into sub-images and their features were extracted to perform classification between clouds and grounds. However, due to the high complexity of clouds and surfaces and the low resolution of browse images, the traditional classification algorithms based on image features are of great limitations. In view of the problem, a prior enhancement processing to original sub-images before classification was put forward in this paper to widen the texture difference between clouds and surfaces. Afterwards, with the secondary moment and first difference of the images, the feature vectors were extended in multi-scale space, and then the cloud proportion in the image was estimated through comprehensive analysis. The presented cloud detection algorithm has already been applied to the ZY-3 application system project, and the practical experiment results indicate that this algorithm is capable of promoting the accuracy of cloud detection significantly.

InSAR can extract one-dimensional deformation along the line of sight of radar. SAR image coregistration and pixel offsets can be used to extract two-dimensional deformation along the azimuth and range directions, and can be considered as the significant complement for InSAR deformation measurement. Analyzing the method of extracting deformation field with the SAR image coregistration and pixel offsets, this paper presents the error model of deformation extraction along the azimuth and range directions. The main error components for deformation extraction from the pixel offsets are addressed. The experiments of coseismic deformation field extraction and error analysis are carried out with ASAR images of Bam earthquake and PALSAR images of Yushu earthquake. The results show that the coseismic deformation extraction accuracy is significantly affected by matching window size and oversampling factor. The deformation extraction error decreases with the increase of matching window size, and deformation extraction accuracy can be slightly improved with the increase of oversampling factor. Terrain effect can cause significant pixel displacements in SAR images over high-relief areas.

The personalization and intelligence of map service ultimately reflects in their symbol design. By establishing conceptual models of personalized map symbols, a theoretical discussion of the symbols is launched from a perspective which both human perceptions and logistic comprehension are considered in this paper, thus to help analyzing the relationship among geographic objects, map symbols and the interpretation of users and exploring the design basis of personalized map symbol. According to some key points such as relevant linguistic theories, the interpretation of the symbol contexts and symbolic statement syntax, design strategies of personalized map symbols is parsed. Thus, methods and processes of personalized map symbol design are proposed accordingly, following by experiments which could verify the hypothesis.

Mitigating the differences of the surface areas computed by DEM data with different resolutions is meaningful in precisely doing area statistics and monitoring area changes. In this paper, we discuss the mathematical models to the surface area computation and give the influences to the computational accuracy. An area computation method of polygons on the landscape surface is proposed and this method has taken local terrain factors into account. Firstly, the least squares estimation of these local terrain factors is achieved by employing the Taylor series expansion of the spatial function, then these estimated terrain factors are applied to the DEM interpolation. Finally, the regular triangulated network is structured to approximate the theoretical area of the landscape surface. Experiments show that, in the mountainous area or hilly region where the nonlinear topographic signal is prominent, the computational area heavily relies on the space resolution of the DEM data and the impact to the surface area computation is very serious. However, due to the using of terrain factors estimated, the area computation strategy proposed can significantly improve the precision of the computed area from the low resolution DEM.

Network schematic map is the abstract representation of entity network. It has been applied in the field of map service and cartography because it is more consistent with people's cognitive habits. The previous route-based auto schematic algorithms have only considered the local arrangement of nodes and are difficult to maintain topological consistency. In reaction to the deficiency, a new polygon-based algorithm is proposed in this paper, which uses the closed polygons (mesh) as the basic unit of the network for their independence and adjacency. The network is regarded as closed polygons and non-closed line segments. The main progress is extracting, mapping and combining closed polygons. Experimental analysis shows that this algorithm is more effective in balancing network spatial distribution and maintaining topological consistency.

In order to evade the ill-posedness of downward continuation for airborne gravity data using traditional inverse Poisson integral, in a recent published article,a practical downward continuation method of airborne gravity data was used for the sea surveying areas using the differential conception in navigation and location for reference, in which the continuation corrections are calculated using ultra-high-degree geopotential model. In this paper, we continue using the same idea and develop the method to the application for land surveying areas. It suggests that terrain Information can be used to improve the calculated accuracy of continuation correction from geopotential model. The differential of local topographic corrections on flying height and corresponding ground point is added to the continuation correction from geopotential model, and it makes up the total continuation correction. It is ultimately realized to continue airborne gravity measurements to the ground in full frequency extension. EGM2008 geopotential model, ground gravity data and digital elevation model in high resolution are used as a case study to prove the efficiency of the new method.

The predicted residual vectors should be zero-mean Gaussian white noise, which is the precondition for multiple fading factors adaptive filtering algorithm based on statistical information in GPS/INS integration system. However the abnormalities in observations will affect the distribution of the residual vectors. In this paper, a neural network aided adaptive unscented Kalman filter (UKF) algorithm with multiple fading factors based on singular value decomposition(SVD) is proposed. The algorithm uses the neural network algorithm to weaken the influence of the observed abnormalities on the residual vectors. Singular value decomposition instead of unscented transformation is adopted to suppress negative definite variation in priori covariance matrix of UKF. Since single fading factor in poor tracking of multiple variables has the limitation, multiple fading factors to adjust the predicted-state covariance matrix are constructed with better robustness so that each filter channel has different adjustability. Finally, vehicle measurement data are collected to validate the proposed algorithm. It shows that the neural network algorithm can prevent the observed abnormalities from affecting the distribution of the residual vectors, expanding the applied range of the adaptive algorithm. The neural network algorithm aided SVD-UKF algorithm with multiple fading factors is able to remove influences of state anomalies on condition of the observed abnormalities. The accuracy and reliability of the navigation solution can be improved by this algorithm.

Presently, many IGS tracking stations have been equipped with high performance atomic clocks. In this paper, the modified Allan variance method is used to analyze the time-domain characterization of random noise of receiver clocks from different IGS tracking stations. Then, we not only evaluate the short-term stability of different types of receiver clock and the feasibility of clock modeling, but also take advantage of the observational data of Active Hydrogen Maser from IGS station in order to constrain random variation of receiver clock offset by implementing short-term clock modeling in precise point positioning(PPP) algorithm and improve positioning performance of PPP. The experiment results show that the method of clock modeling reduces the correlation between the height component, the zenith path delay and receiver clock offset parameter, the accuracy of height component can be improved by 50%. The proposed method can improve the PPP performance in crustal deformation monitoring, LEO satellite orbit determination, GNSS methodology and many other high precise GNSS geoscience fields when a high-performance atomic clock is deployed.

Satellite platform jitter is one of the factors that affect the quality of high resolution imagery, which can cause image blur and internal distortion. Taking ZiYuan-3 (ZY-3) multi-spectral camera as a prototype, this paper proposes a satellite platform jitter detection method by utilizing multi-spectral imagery. First, imaging characteristics of multispectral camera and the main factors affecting band-to-band registration error are introduced. Then the regularity of registration error caused by platform jitter is analyzed by theoretical derivation and simulation. Meanwhile, the platform jitter detection method based on high accuracy dense points matching is presented. Finally, the experiments were conducted by using ZY-3 multi-spectral imagery captured in different time. The result indicates that ZY-3 has a periodic platform jitter about 0.6 Hz in the imaging period of test data, and the jitter amplitude across track is greater than that along track, which causes periodic band-to-band registration error with the same frequency. The result shows the possibility of the improvement in geometric processing accuracy for ZY-3 imagery products and provides an important reference for satellite platform jitter source analysis and satellite platform design optimization.

Detection of the damaged building is the obligatory step prior to evaluate earthquake casualty and economic losses. It's very difficult to detect damaged buildings accurately based on the assumption that intact roofs appear in laser data as large planar segments whereas collapsed roofs are characterized by many small segments. This paper presents a contour cluster shape similarity analysis algorithm for reliable building damage detection from the post-earthquake airborne LiDAR point cloud. First we evaluate the entropies of shape similarities between all the combinations of two contour lines within a building cluster, which quantitatively describe the shape diversity. Then the maximum entropy model is employed to divide all the clusters into intact and damaged classes. The tests on the LiDAR data at El Mayor-Cucapah earthquake rupture prove the accuracy and reliability of the proposed method.

This paper proposed a quick, affine invariance matching method for oblique images. It calculated the initial affine matrix by making full use of the two estimated camera axis orientation parameters of an oblique image, then recovered the oblique image to a rectified image by doing the inverse affine transform, and left over by the SIFT method. We used the nearest neighbor distance ratio(NNDR), normalized cross correlation(NCC) measure constraints and consistency check to get the coarse matches, then used RANSAC method to calculate the fundamental matrix and the homography matrix. And we got the matches that they were interior points when calculating the homography matrix, then calculated the average value of the matches' principal direction differences. During the matching process, we got the initial matching features by the nearest neighbor(NN) matching strategy, then used the epipolar constrains, homography constrains, NCC measure constrains and consistency check of the initial matches' principal direction differences with the calculated average value of the interior matches' principal direction differences to eliminate false matches. Experiments conducted on three pairs of typical oblique images demonstrate that our method takes about the same time as SIFT to match a pair of oblique images with a plenty of corresponding points distributed evenly and an extremely low mismatching rate.

Ambiguous visual structures or repetitive textures of different scenarios would result in a large number of mismatching points in image matching stage, and false positive relative orientation is introduced which is locally consistent.In this paper, the probabilistic inference method is introduced and an improved detection algorithm of false positive relative orientations is presented. A Bayes network based on relative orientations between images is constructed using closed cycle constraints and priori probability models in Bayes network is derived and the maximum posterior probability in Bayesian network is solved using belief propagation algorithm. Experimental results show that using the proposed global consistency constraints method can effectively detect the false positive relative orientations and improve outcomes of scene reconstruction with high computational efficiency.

Thermal expansion of GPS monuments and nearby bedrock could result in vertical changes in the coordinate time series of GNSS reference stations. In this paper, an improved method was developed to compute the magnitude of vertical variations caused by thermal expansion. Firstly, we calculated the effect on GPS monument and bedrock caused by thermal expansion based on land surface temperature data of GNSS reference stations and thermal expansion model. Secondly, we estimated the circular frequencies, amplitudes and phases using the method of least squares fitting instead of the current method which estimated only the amplitudes and phases information. Finally, we studied the periodic characteristics of the vertical variations caused by our modified thermal expansion model. Through analyzing the results of 9 representative IGS stations, we concluded that thermal expansion of GPS monuments and nearby bedrock could result in vertical variations of GNSS stations. The maximum variations could reach up to 0.57 mm and 1.85 mm at these stations respectively. The vertical variation caused by thermal expansion exhibited both annual and semiannual characteristics, which could explain 11.2% and 3.3% of the total annual and semi-annual variations in the up component of the coordinate time series respectively, and the magnitudes became larger with the increasing of their latitudes. Meanwhile, the amplitudes of the annual variations were much larger than that of the semi-annual variations. Meanwhile, some other small period (about 51 days) was also detected at some of these stations. In addition, we chose 107 IGS reference stations and computed the annual amplitudes and phases caused by thermal expansion of all these stations based on the method aforesaid. The results show that the maximum annual amplitude can reach to 3.3 mm, and their magnitudes show positive correlation with their latitudes prominently.

It is difficult to estimate the Doppler frequency and modulating rate for airborne SAR by using traditional vector method due to instable flight and complex terrain. In this paper, it is qualitatively analyzed that the impacts of POS, DEM and their errors on airborne SAR Doppler parameters. Then an innovative vector method is presented based on the range-coplanarity equation to estimate the Doppler centroid taking the POS and DEM as auxiliary data. The effectiveness of the proposed method is validated and analyzed via the simulation experiments. The theoretical analysis and experimental results show that the method can be used to estimate the Doppler centroid with high accuracy even in the cases of high relief, instable flight, and large squint SAR.

In order to study SAR land cover classification method, this paper uses the multi-dimensional combination of temporal,polarization and InSAR data. The area covered by space borne data of ALOS PALSAR in Xunke County,Heilongjiang Province was chosen as test site. A land cover classification technique of SVM based on multi-temporal, multi-polarization and InSAR data had been proposed, using the sensitivity to land cover type of multi-temporal, multi-polarization SAR data and InSAR measurements, and combing time series characteristic of backscatter coefficient and correlation coefficient to identify ground objects. The results showed the problem of confusion between forest land and urban construction land can be nicely solved, using the correlation coefficient between HH and HV, and also combing the selected temporal, polarization and InSAR characteristics. The land cover classification result with higher accuracy is gotten using the classification algorithm proposed in this paper.

To take into account all of efficiency and query capability, this paper presents a new trajectory data index named HBSTR-tree. In HBSTR-tree, trajectory sample points are collectively stored into trajectory nodes sequentially. Hash table is adopted to index the most recent trajectory nodes of mobile targets, and trajectory nodes will not be inserted into spatio-temporal R-tree until full, which can enhance generation performance in this way. Meantime, one-dimensional index of trajectory nodes in the form of B*-tree is built. Therefore, HBSTR-tree can satisfy both spatio-temporal query and target trajectory query. In order to improve search efficiency, a new criterion for spatio-temporal R-tree and one new node-selection sub-algorithm are put forward, which further optimize insertion algorithm of spatio-temporal R-tree. Furthermore, a database storage scheme for spatio-temporal R-tree is also brought up. Experimental results prove that HBSTR-tree outperforms current methods in several aspects such as generation efficiency, query performance and supported query types, and then supports real-time updates and efficient accesses of huge trajectory database.

When observing the Earth from above at night, it is clear that the human settlement and major economic regions emit glorious light. At cloud-free nights, some remote sensing satellites can record visible radiance source, including city light, fishing boat light and fire, and these nighttime cloud-free images are remotely sensed nighttime light images. Different from daytime remote sensing, nighttime light remote sensing provides a unique perspective on human social activities, thus it has been widely used for spatial data mining of socioeconomic domains. Historically, researches on nighttime light remote sensing mostly focus on urban land cover and urban expansion mapping using DMSP/OLS imagery, but the nighttime light images are not the unique remote sensing source to do these works. Through decades of development of nighttime light product, the nighttime light remote sensing application has been extended to numerous interesting and scientific study domains such as econometrics, poverty estimation, light pollution, fishery and armed conflict. Among the application cases, it is surprising to see the Gross Domestic Production (GDP) data can be corrected using the nighttime light data, and it is interesting to see mechanism of several diseases can be revealed by nighttime light images, while nighttime light are the unique remote sensing source to do the above works. As the nighttime light remote sensing has numerous applications, it is important to summarize the application of nighttime light remote sensing and its data mining fields. This paper introduced major satellite platform and sensors for observing nighttime light at first. Consequently, the paper summarized the progress of nighttime light remote sensing data mining in socioeconomic parameter estimation, urbanization monitoring, important event evaluation, environmental and healthy effects, fishery dynamic mapping, epidemiological research and natural gas flaring monitoring. Finally, future trends of nighttime light remote sensing and its data mining have been proposed from four aspects including new data source, knowledge discovery, in-situ observation, and national/global geographic conditions monitoring.

Based on the Newton-Gauss iterative algorithm of weighted total least squares (WTLS), a robust WTLS (RWTLS) model is presented. The model utilizes the standardized residuals to construct the weight factor function and the square root of the variance component estimator with robustness is obtained by introducing the median method. Therefore, the robustness in both the observation and structure spaces can be simultaneously achieved. To obtain standardized residuals, the linearly approximate cofactor propagation law is employed to derive the expression of the cofactor matrix of WTLS residuals. The iterative calculation steps for RWTLS are also described. The experiment indicates that the model proposed in this paper exhibits satisfactory robustness for gross errors handling problem of WTLS, the obtained parameters have no significant difference with the results of WTLS without gross errors. Therefore, it is superior to the robust weighted total least squares model directly constructed with residuals.

Using gravity / gravity gradient data for Moho inversion, one of the key steps is how to extract the Moho information data precisely from raw measurements. Here we mainly discussed:①In order to eliminate the error of point mass model used by GEMMA Moho research team, we choose Tesseroid in space domain and harmonic analysis and synthesis method in frequency domain; ②The reasonable use of priori crustal model. Based on GOCO03S model, we provide the gravity gradient disturbing results of three main components which are for Moho inversion. Finally, all experiment results are discussed and analyzed in this paper.

In order to satisfy the requirement of identification and tracking the elliptical artificial targets fast and accurately for the image sequences from videogrammetric measurement for structural health monitoring, this paper proposes a systemic algorithm to identify and track the elliptical targets using the image block technique. The proposed method extracts the image block from original images to reduce the amount of data processing for the oval targets tracking. The mathematical morphology and elliptical geometric characteristics are integrated to eliminate the non-elliptical edge information to extract the elliptical contour in the range of image block. At last, the sub-pixel center location for elliptical artificial targets is acquired by the least square algorithm. The experimental results show that RMS error of 0.025 pixel can be achieved by the proposed method, furthermore, compared with the random Hough transform and template recognition algorithm, the tracking efficiency is improved over 5 times.

A topology adaptive snake (T-Snake) model based on orthogonal grids is introduced and improved in this paper, and a proper energy function is designed. A detection and handling mechanism for topological conflict that caused by island shaped hollow is proposed in the model, and therefore accurate extraction for complex boundary of river containing river islands is achieved. For the disadvantage of the need to manually construct the initial contour in the orthogonal T-Snake model, using the minimum fractal dimension to obtain one area of the water and automatically generate an initial contour. The experiment shows that the algorithm of this paper can accurately extract the boundary of the complex water which contains deeply concave regions or river islands, and it has higher accuracy and less time cost than classic Snake model and GVF Snake model.

With the development of remote sensing technology, especially the improvement of sensor resolution, the amount of image data is increasing. This puts forward higher requirements to manage huge amount of data efficiently and intelligently. And how to access massive remote sensing data with efficiency and smartness becomes an increasingly popular topic. In this paper, against current development status of Spatial Data Management System, we proposed a self-adaptive strategy for image blocking and a method for LoD(level of detail)model construction that adapts, with the combination of database storage, network transmission and the hardware of the client. Confirmed by experiments, this imagery management mechanism can achieve intelligent and efficient storage and access in a variety of different conditions of database, network and client. This study provides a feasible idea and method for efficient image data management, contributing to the efficient access and management for remote sensing image data which are based on database technology under network environment of C/S architecture.

The widely used random volume over ground (RVOG) model in forest height inversion with polarimetric SAR interferometric (PolInSAR) technology do not consider the effect of terrain slope. Besides, the classical and widely applied three-stage inversion method is affected by the errors about estimation of underlying topography phase and pure volume coherence. In order to correct these two types of errors, a forest height inversion strategy is proposed. On the one hand, a slope RVOG (S-RVOG) model is adopted in this paper which incorporates the range terrain slope factor to correct the terrain distortion; on the other hand, the phase diversity (PD) coherence optimization is introduced to improve accuracy of underlying topography phase estimation in line fit process and pure volume coherence estimation. In order to verify efficiency of the method, a simulation experiment is carried out by using PolInSAR data in different range slope levels simulated by PolSARpro software provided by ESA. Then, E-SAR airborne full polarization data provided by DLR are utilized to test real scenario. Finally, it is conducted that some qualitative and quantitative analyses. The results show that for the different data in different range slope levels, the inversion method promises to correct effect due to terrain distortion in RVOG model and compensate error effect in traditional three-stage inversion method. Therefore, the proposed method provides much more accurate estimation of forest parameters.