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Table of Content

    25 February 2019, Volume 0 Issue 2
    Development of underwater gravity measurement technologies
    PAN Guowei, CAO Juliang, WU Meiping, TIE Junbo
    2019, 0(2):  1-5.  doi:10.13474/j.cnki.11-2246.2019.0033
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    This paper introduces the concept of underwater gravity measurement at first, and then analyzes the necessity of underwater gravity measurement. It briefly illustrates its whole development history in the second part, in which the advantages and disadvantages of two mainstream schemes, including underwater gravity measurement based on ROV and underwater gravity measurement based on AUV, are discussed. In the third part, we introduce the latest development at home and abroad, typically including the near-bottom gravimetry based on a cas-cade connected ROV named TOWDOG, from University of California, and a series of underwater gravimetry using AUV,from the University of Tokyo. At last, it presents the research emphases and the near future development of this field in China.
    Time series analysis of geocenter motion based on EMD method
    QIAO Lingna, ZHAO Chunmei, MA Tianming
    2019, 0(2):  6-11.  doi:10.13474/j.cnki.11-2246.2019.0034
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    The high-frequency information mixed with geocenter motion time series will affect the analysis of the geocenter motion. This paper uses the EMD method to decompose and reconstruct the geocenter motion time series from 2007 to 2017 calculated by translation approach using the GNSS solution provided by the IGS, then removes high-frequency terms, and performs the further analysis using the reconstructed geocenter motion time series. The results show that the geocenter motion calculated in the Tx, Ty, and Tz directions are at the millimeter level. The reconstructed time series using EMD method preserves the basic information of the original time series, weakens the influence of high-frequency terms, and improves the contribution rate of each periods, contribution rate in three directions increase by 12.3%, 16.7% and 6.3% respectively. By analyzing the reconstructed time series, the annual amplitudes in three directions are maximum, compared to other period, which are 2.32, 1.89, and 2.07 mm, respectively. In addition, the long-term trends in the Ty and Tz directions are more pronounced than those of Tx, which are 0.13 and -0.27 mm/a, respectively. The semi-annual term is weak and has a time variant features in the Tx and Ty directions. Moreover, some other minor interannual variations have also been discovered.

    Application of star recognition algorithm based on video measuring robot in automatic astronomical orientation
    YE Kai, ZHANG Chao, SHI Chunlin, MI Kefeng, ZHAN Yinhu
    2019, 0(2):  12-16,44.  doi:10.13474/j.cnki.11-2246.2019.0035
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    Astronomical orientation is a high precision orientation method to determine the orientation by observing celestial bodies, which plays an important role in astronomical measurement. Automatic astronomical orientation is the developing trend of astronomical orientation. Based on video total station work mode, a star identification orientation method is proposed. First, it uses video measuring to continuously and rapidly shoot many stars. Second, all the stars are identified with the elevation angle and azimuth angle difference as matching conditions. Finally, the directional results are obtained by using the observed data and the calculated stellar data relation, to realize the automatic astronomical orientation. In this paper, the star recognition error caused by coordinate error of measurement station and observation error is analyzed. Therefore, the matching threshold is given to further improve the precision and accuracy of matching.

    Indoor positioning system based on trilateration and PDR fusion
    CHEN Peng, LIAO Ming, LIU Wuping, GUO Wei, SONG Yang
    2019, 0(2):  17-21.  doi:10.13474/j.cnki.11-2246.2019.0036
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    The indoor positioning has been improved significantly with the development of wireless indoor positioning technology. However, it is difficult to obtain continuous positions only using a wireless positioning method, which makes the positioning point jitter without good user experience. Practical applications require a variety of technical tools. Different hardware platforms will affect the specific combination. In this paper, we propose a method fusing the trilateration and PDR, and using map matching to correct results in order to get continuous and stable positioning results based on the WeChat platform. Then, we use indoor map visualization technology to visualize the components of the indoor positioning system. Finally, an indoor positioning system based on the WeChat platform is developed. The system has already been applied in the actual scene and has good positioning results.

    Denoising from remote sensing satellite image based on two-dimensional EMD and adaptive Gauss filtering
    WANG Yueyue, CHEN Rong, YU Lijun, ZHU Jianfeng, WU Yufeng, CHEN Xuanchi
    2019, 0(2):  22-27.  doi:10.13474/j.cnki.11-2246.2019.0037
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    When traditional method of denoising from remote sensing image is used to remove image noise, it often causes the loss and blur of image details after denoising. In this paper, the two-dimensional EMD denoising theory is applied to the denoising of remote sensing images. An improved denoising algorithm for remote sensing images combined with two-dimensional EMD and adaptive Gaussian filtering is proposed. When denoising, the low-frequency information remains unchanged, only for the high-frequency information of the image. Different frequency IMF component maps after two-dimensional EMD decomposition use adaptively Gaussian filtering to denoise, so as to better denoise the noisy image. Through the comparative analysis of two groups of experiments shows that:the algorithm has larger peak signal to noise ratio, average gradient and structural similarity and smaller RMS error. And the edge detection results also show that when the noise is filtered out, the image after this algorithm denoising can be better retain the details and the edge profile information of the original image. All these show that the algorithm has better denoising effect.

    A denoising method of mixed noise of remote sensing image
    DENG Kaiyuan, REN Chao, LIANG Yueji, YU Zhiwen
    2019, 0(2):  28-31,70.  doi:10.13474/j.cnki.11-2246.2019.0038
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    In order to weaken the influence of remote sensing image noise and improve the use value of imagery, a new combined filtering method is proposed for the mixed noise denoising of remote sensing images, namely the denoising method based on three-dimensional block matching and adaptive median filtering. The rbio3 wavelet and db20 wavelet replace the traditional three-dimensional block matching parameters. Two simulation experiments and one real remote sensing image denoising experiment are performed. The results show that this method is better than the traditional filtering method in removing the common pulse and Gaussian noise of remote sensing images.

    Line feature extraction from LiDAR point cloud of unmanned vehicle platform
    CAI Binbin, LI Bijun
    2019, 0(2):  32-38.  doi:10.13474/j.cnki.11-2246.2019.0039
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    As the application of unmanned platforms is becoming more and more widespread, building high-precision feature maps by extracting line features from LiDAR point cloud has also become the focus of research. In this paper, a new geometric model is proposed to obtain accurate 3D line features based on the 2D line features of the depth image. The Bayesian filter is used to fuse the results of multiple frames to improve the precision and accuracy of the 3D line features.

    Quantitative expression of fields of view under close range photogrammetry
    XIAO Yi, LIU Peng, WANG Yu, ZHANG Wenjing, ZHANG Sijia
    2019, 0(2):  39-44.  doi:10.13474/j.cnki.11-2246.2019.0040
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    The relationship at the field of view under close range photogrammetry refers to position and pose relationship at different fields of view in a small space range, which is used to determine the rotation and translation of the reference coordinates, represented by different cameras.Under the framework of close range photogrammetry, a method for determining the position and pose between two different fields of view is proposed in this paper, of which the concrete steps are:①Change detection from the large field of view,when the change area is detected, the original image is obtained at the same time,and the sample images set were obtained under the small field of view. ②The original photo and the sample photos are relatively orientated, and the spatial attitude parameters of the sample photos relative to the original photo are obtained. ③The original image is matched with the sample images to obtain the sample image with the highest matching degree,the attitude parameters of the sample image are the spatial position and pose of the samll field of view relative to the large field of view. ④According to the attitude parameters obtained in step 3, the camera position and pose is adjusted under the small field of view so that it can be aligned to the changing area. Experiments show that this method can effectively support the quantitative description of the field of view in a small range.

    Reconstruction of urban dense point cloud surface model using graph-cuts algorithm
    MA Dongling, WANG Xiaokun, LI Guangyun
    2019, 0(2):  45-48.  doi:10.13474/j.cnki.11-2246.2019.0041
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    The construction of surface model by using dense point cloud obtained from oblique image is one of the core of 3D reconstruction based on oblique images. For the problems of low modeling efficiency and unreal surface selection in the current dense point cloud surface model reconstruction, a new method of urban dense point cloud surface model reconstruction based on graph-cuts algorithm is proposed. This method is used to reconstruct the surface model of the urban dense point cloud. First, the aerial triangulation of the unmanned aerial vehicle (UAV) image is done by the preprocessing software, and the dense point cloud is generated by the results of the aerial triangulation, then the corresponding edges are added to the dense point cloud, and the 3D point clouds are selected and merged according to the distance. Finally, a graph-cuts problem is established based on the tetrahedron and triangulation formed by the 3D point cloud, and an optimal dense point cloud surface model is obtained by solving the graph-cuts problem. In order to prove the feasibility and effectiveness of this method, the UAV image data in urban areas is used to reconstruct the urban dense point cloud surface model, and the experimental results show that the method has the advantages of good feasibility, good modeling effect, fast processing speed and so on.

    Three dimensional modeling method of stalactite integrated with multi-source measurement data
    GUO Yu, XIA Yonghua, YANG Minglong
    2019, 0(2):  49-53.  doi:10.13474/j.cnki.11-2246.2019.0042
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    In the tourism development of karst caves, the traditional topographic map can not describe the details of the stalactite in the cave, and it is difficult to meet the requirements of the planning, design and construction in the development of the cave. Taking a three-dimensional reconstruction project of a medium-sized cave as an example, a three dimensional laser scanning data and a multi baseline close range photogrammetry data are put forward. Three dimensional reconstruction method of stalactite is supplemented by multi-source data fusion. First, the fusion and registration of multi-source data are completed. Secondly, the model reconstruction after the registration is carried out and a variety of different methods are used to carry out the cavitation area repair comparison experiment. The method of data fusion can effectively supplement the blind area of the three-dimensional laser scanning data in the narrow space area, and improve the fine degree of the 3D model. The development, protection, 3D reconstruction and visualization of karst caves are of some reference significance.

    An improved accuracy evaluation method of urban ground subsidence monitoring in InSAR
    YANG Fan, WANG Daoshun, ZHANG Lei, ZHANG Ziwen
    2019, 0(2):  54-57,85.  doi:10.13474/j.cnki.11-2246.2019.0043
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    Aiming at the singleness of the method which is to assess InSAR settlement monitoring accuracy, considering the problems of self-sedimentation of buildings and space-time benchmarks difficult to be unified, an improved inverse distance weights interpolation model is proposed. The experimental data are the PS-InSAR monitoring result of a subsidence area in Ningbo New City East, and the accuracy of the monitoring results is evaluated using the improved IDW interpolation model on the premise of a unified space-time reference, and the accuracy of the interpolation method is verified by a cross-validation method. Experiments show that the error of InSAR monitoring results obtained using the improved IDW interpolation is 0.3 and 0.8 by comparing two measured points. Compared to the normal IDW and Kriging methods, it is about 1.1 mm.

    A SBAS InSAR time series ground deformation extraction approach considering permanent scatterers
    WANG Shunyao, LU Xiaoping, LIU Xiaobang, FU Suining
    2019, 0(2):  58-62,70.  doi:10.13474/j.cnki.11-2246.2019.0044
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    A SBAS InSAR time series ground deformation extraction approach considering permanent scatterers is proposed in this paper. The stable permanent scatterers are extracted by setting the three thresholds of coherence, amplitude dispersion index and deformation rate, and are used as the ground control points in SBAS InSAR process to extract the ground deformation. A case study of Zhengzhou is conducted. The ground deformation rate and time series ground deformation of Zhengzhou from November 2016 to November 2017 are extracted. By comparing with PS InSAR, SBAS InSAR processing results and leveling measurements, and the reliability of this approach is well demonstrated.

    Adaptive surface modeling of soil total potassium content based on integrated learning support in complex geomorphological regions
    LIU Yongkun, LIU Wei, WANG Changyang, CHEN Jiaming, MA Jin
    2019, 0(2):  63-70.  doi:10.13474/j.cnki.11-2246.2019.0045
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    The spatial distribution of soil attributes is influenced by the elements of complex geoscience environment, and the spatial differentiation characteristics are very obvious. It is difficult to simulate soil attributes with a single global interpolation model. For the characteristics of spatial discontinuity, limited precision of global interpolation model and poor adaptability, a soil attribute adaptive surface modeling method(ASM-SP) based on integrated learning support and integrated geoscience environment variables was proposed. Based on 110 samples collected in 2013, regression Kriging(RK), Bayesian Kriging (BK), ordinary Kriging(OK) and inverse distance weighting method(IDW), ASM-SP were used to interpolate the soil total potassium content in the complex geomorphological area of Qinghai Lake, respectively. In this paper, the simulation accuracy of different interpolation methods was evaluated by Leave One Out Validation. ASM-SP not only considers the nonlinear relationship between geo-environmental variables and soil attributes, but also combines the adaptive advantages of multiple models. It is a new method to simulate soil total potassium content in complex geomorphological regions with high precision.

    Population simulation study of Nanjing streets from multi-source information and multi-scale perspective
    XU Lingli, YAN Meichun
    2019, 0(2):  71-75.  doi:10.13474/j.cnki.11-2246.2019.0046
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    Population is an important social and ecological environmental factor, and mastering population information is beneficial to resource allocation and environmental management. This paper takes Nanjing's street-level administrative region as the basic object unit, and uses NPP/VⅡ RS night light data, POI data in big data and IBI of LANDSAT 8 satellite OLI image from the three scales of city level, suburb level and urbanization level, population size and population density. The results show that at the municipal level, the effect of population density simulation is better than that of the total population, POI data simulation is the best, with certainty coefficient of 0.87, followed by building land index of 0.81 and night light number of 0.77. At the suburban level, the fitting effect of the population density in the suburbs is better than that in the urban areas. In terms of urbanization degree, the power function relationship between the street population density of moderate urbanization and NPP/VⅡRS is the best, with the certainty coefficient of 0.99, while the logarithmic relationship between the street population density of low and high urbanization and POI is better, with the certainty coefficients of 0.65 and 0.44, respectively. The multivariate linear regression model of the total population and the data of three factors in the medium and low urbanization streets has the best effect, with the certainty coefficients of 0.91 and 0.78, respectively. It shows that the population simulation effect of moderately urbanized streets is the best. This study expands the breadth and depth of urban population estimation and can provide a reference for related work.

    Description of indoor space model with IndoorGML
    YUAN Debao, YAN Yu, WANG Bingling
    2019, 0(2):  76-79,85.  doi:10.13474/j.cnki.11-2246.2019.0047
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    The expression of the indoor spatial model is a key factor affecting the indoor location service.Before conducting the indoor spatial location service,it is necessary to establish a model that can express the complex features of the indoor space. Therefore, this paper proposes a multivariate hybrid indoor space model based on the traditional object feature model, geometric space model and symbol space model.The multivariate hybrid indoor space model is achieved through an optimal combination of the geometric and topological features expressed, which can fully express the connectivity relationship between indoor location and target,and meet the needs of indoor location service. For a large number of applications that need the same model for navigation analysis and information exchange, this paper proposes a method to describe the indoor space model using IndoorGML. This method can achieve the sharing of indoor space model information on each device side. Taking a large shopping mall in Beijing as an example, a multivariate hybrid space model of the mall was established and described using IndoorGML. Finally, the application of the proposed method was proved by the analysis of the path between two objects.

    A genetic taboo search algorithm for point-feature label placement considering the constrain of road network
    LI Juan, ZHU Qindong
    2019, 0(2):  80-85.  doi:10.13474/j.cnki.11-2246.2019.0048
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    This paper implements a genetic taboo search algorithm combined with global optimization capability of genetic algorithm and the memory and climbing ability of tabu search to solve the point-feature label placement problem. In addition to the constraints of the traditional point element annotation configuration, this method joins the constraints of the line feature to restrain the point-feature label placement. Moreover, the solution accuracy, efficiency and robustness of the algorithm is evaluated. The paper takes the rural topographic map data at 1:200 000 in Huian county of Quanzhou city, Fujian province. The results show that the genetic taboo search algorithm has higher solution accuracy and robustness than the genetic algorithm and tabu search, lower efficiency than the tabu search, and all three indexs higher than the ArcGIS, as well as the less crossover and overlap than the other three methods.

    Research on GNSS-R sea surface target imaging simulation method
    ZHANG Yuandi, JIAO Ruili, ZHU Yunlong, WU Shiyu
    2019, 0(2):  86-90,107.  doi:10.13474/j.cnki.11-2246.2019.0049
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    Based on scattering theory in high-frequency, this paper presents a new GNSS-SAR imaging model. The model takes GNSS signal as sources, describes the influence of electromagnetic scattering on GNSS-SAR imaging on sea surface, with the combination of physical optic methods and four-path method, which has been used in some traditional composite models on electromagnetic scattering calculation. Besides, the effects of multi-path scattering, shadowing, and diffuse scattering are also considered. According to electromagnetic scattering theory, we have analyzed the disturbance of wind speed on sea surface. In conclusion, in the scenario we simulated in paper, the target can be recognized if wind speed is 9 m/s, but when wind speed comes to 17 m/s, the recognition will fail.

    Plane coordinate conversion methods and precision analysis in consideration of topographic relief
    MA Haiying, HU Yueming, YAO Chaolong, FAN Yanan, HU Bixia, ZHANG Wei
    2019, 0(2):  91-94,112.  doi:10.13474/j.cnki.11-2246.2019.0050
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    The precision of coordinate conversion is impacted by various factors, such as conversion methods, the number and distribution of public points, and topography. Taking mining right inspection data in Qinghai plateau as an example, this paper made plane coordinate transformation using four parameters model and the quadratic surface model. The impacts of the selection of public points on coordinate transformation in undulate terrain and the features of the two plane coordinate transformation methods were explored. The results of this study provided helpful information for the related engineering applications.

    Accuracy analysis of GPS static precise point positioning algorithm
    FU Huanian, ZHANG Xudong, HU Yukun
    2019, 0(2):  95-98.  doi:10.13474/j.cnki.11-2246.2019.0051
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    This paper uses precision orbit and clock difference to calculate thirteen IGS tracking stations' coordinates, tropospheric ZTD and receiver clock difference in Asia by Bernese software. Compared with the results issued by CODE, it is found that the N direction convergence accuracy of the static PPP algorithm is obviously better than E direction and U direction, and the coordinate deviation after 4 to 6 hours nearly 1 cm, the NEU RMS mean is 0.45, 0.29, 0.69 cm, ZTD RMS mean is 0.85 cm, receiver clock difference RMS mean is 0.14 ns. The experiment shows that the precision single point positioning algorithm has high accuracy and reliability, it can provide theoretical basis for the actual engineering measurement and related geophysical signal research.

    Research progress of deep learning in classification and recognition of remote sensing images
    WANG Bin, FAN Donglin
    2019, 0(2):  99-102,136.  doi:10.13474/j.cnki.11-2246.2019.0052
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    The concept of deep learning has been a hot topic in machine learning and artificial intelligence since it was put forward. In particular, the deep learning, a deep neural network learning machine algorithm, is closely combined with the classification and recognition of remote sensing images, so that the local minimization of the traditional training algorithm can be solved. This paper briefly introduces the development of remote sensing image classification and recognition algorithms and the limitations of classical algorithms. Secondly, it introduces several mainstream algorithms of deep learning and analyzes their application status in remote sensing image classification and recognition processing. Finally, the future trend of application of deep learning in remote sensing recognition and classification is prospected.

    Automatic classification of GF-2 remote sensing imagery based on active learning and bag of visual words model
    ZHANG Jinying, YAO Guanghu, LIN Lin, GUO Huaixuan
    2019, 0(2):  103-107.  doi:10.13474/j.cnki.11-2246.2019.0053
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    The improvement of high-resolution satellite images makes the spectrum and texture more rich and complex, which poses challenges for the automatic classification. Therefore, this paper combines active learning and bag of word model for image classifications. First, a multi-scale segmentation is implemented to generate image objects. Second, bag of word model is used to establish the semantic feature of image object. Finally, the uncertainty sample distribution is well considered, and the optimal samples are selected iteratively for training SVM to classify image. To verify the effectiveness and robustness, the high-resolution image in Shandong province was used as experimental data. The results show that the proposed method can effectively classified the study area into four types:water, ground, vegetation, and building, with the overall accuracy of over 90.6%.

    The study and practice on data quality inspection method of city real 3D model based on oblique photography
    LIU Zengliang, CHEN Si, CHEN Pinxiang
    2019, 0(2):  108-112.  doi:10.13474/j.cnki.11-2246.2019.0054
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    Based on oblique photography, high-precision ctiy real 3D model data can be obtained quickly. This paper analyzes the characteristics of real 3D model data, and discusses the key content and quality element of real 3D model data quality inspection. Taking Beijing large-scale real 3D model data quality inspection as an example, the problem and content of real 3D model data quality inspection are summarized. Finally, the quality inspection method of real 3D model data is proposed.

    New application of ship-borne combined laser and bathymetric surveying technique in wharf reconstruction project
    GUAN Minglei, CHEN Zhipeng, LI Qingquan, ZHU Jiasong
    2019, 0(2):  113-116.  doi:10.13474/j.cnki.11-2246.2019.0055
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    In the process of the demolition of the old pile of Haixing pier in Shenzhen Mawan port, to avoid the remaining pile collide with the on the new pile in the new construction of the wharf, it is necessary to make a precise position of the remaining pile. The position of the remaining pile can be accurately calculated by knowing the point location and the pile slope. In this paper, the ship-borne combined laser and bathymetric surveying technique is used to survey the point location and the pile slope of the remaining pile. We used the laser scanner and multi-beam system to measure the point cloud of the water diversion surface of the pile on the water and underwater, respectively. We used the absolute coordinates of the laser point cloud with high accuracy, the point cloud of the water surface of the underwater pile is jointed, and the high precision absolute position of the water surface of the pile is obtained. Then, according to the absolute position of the water surface and the size of the pile, the point and slope of the part below the mud surface of the piles are calculated accurately. Absolute accuracy of pile positioning is 10 cm, which is verified by the location of wharf characteristic points. Finally, the measurement results of the old piles are compared with the design results of the new pile. The results show that there is a collision between new and old piles in the berth 2#, and 10 new piles and old piles in the berth 4# with a horizontal interval of less than 10 cm, which may occur in the construction process.

    Construction of informational evaluation system for mapping and geographic information skill competition
    LI Chong, ZENG Chenxi, YANG Jianyi, DENG Zhiwen
    2019, 0(2):  117-120.  doi:10.13474/j.cnki.11-2246.2019.0056
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    This paper presents a method to construct the information system for the evaluation of occupation skill competition of surveying and mapping geographic information industry, based on the network communication technology, database technology, information technology and geographic information data quality theory. The overall pattern consist a management platform and a lot of evaluation system. Hierarchical structure is the basic technology structure of the system. The strong expansibility and flexible function can effectively eliminate the interference of human factors on the evaluation results, and greatly improves the work efficiency of the referee system. It has been applied in the country.

    Design and implementation of quality inspection system for urban underground integrated pipeline
    LI Yunjian, LI Chong, SHE Dongjing, YANG Jianyi
    2019, 0(2):  121-124,140.  doi:10.13474/j.cnki.11-2246.2019.0057
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    According to the survey data of city underground pipeline and content, high quality requirements, the traditional examination method is difficult to meet the accurate and efficient to carry out quality inspection, this paper analyzes the characteristics of comprehensive underground pipeline data, discusses the contents and methods of the quality inspection results, puts forward a scheme of integration within and outside the industry underground pipeline quality inspection the system is composed of plate based on the rapid inspection subsystem and the operators within the industry clusters based on the automatic quality inspection subsystem, the database management mode, the two subsystems can be seamlessly connected to. The application example shows that the system can effectively improve the information degree of quality inspection, improve the efficiency of quality inspection, and ensure the accuracy and reliability of the inspection results.

    Risk assessment of flood disasters in Zhejiang province based on GIS/AHP integration method
    JIANG Wenjing, CHENG Chunmei, ZHANG Yanbei, ZHAO Hong
    2019, 0(2):  125-130.  doi:10.13474/j.cnki.11-2246.2019.0058
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    The assessment of the flood disaster risk using the GIS technology can make up for the lack of spatial display by traditional assessment methods. According to the occurrence characteristics of flood disasters in Zhejiang province, considering the aspects of danger and vulnerability, several factors influencing flood disasters, including rainfall, topography, river network density, population density and percentage of cultivated land, et al were selected. The factors were spatialized using the GIS spatial analysis technology, and the weight of each factor was determined using the analytic hierarchy process (AHP), after which the flood risk assessment map was obtained and a flood disaster risk assessment system of Zhejiang was built based on the Supermap iObjects platform. The results show that the flooding risk in Zhejiang province is generally high, with the highest risk areas located in the coastal areas in the north and the southeast, the higher-risk areas located in the east and the north, the middle of the south Zhejiang and the Jinqu basin, the medium-risk areas located in the west, north, and western Zhejiang province. The analysis results can provide reference for the prevention and management of flood disasters in Zhejiang province.

    Study on spatial pattern of traffic network development based on geographic conditions monitoring data
    HU Chuanwen, LUO Guangfei, YANG Wenjing, NI Xichun
    2019, 0(2):  131-136.  doi:10.13474/j.cnki.11-2246.2019.0059
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    The traffic access index is an important indicator to characterize the spatial pattern of a regional transportation network. Based on the traffic data related to the national geographic conditions monitoring, this study conducts research on the measurement of the accessibility index based on traffic network density and traffic convenience. A set of calculation methods for traffic accessibility index such as kerneldensity analysis, Euclidean distance analysis and attractiveness analysis are introduced, and the traffic network spatial pattern monitoring is carried out in Hangzhou as the pilot area.

    A brief analysis for the notation of the place names near the national boundary line on the public map of China
    CHEN Huixian, BAI Jinghui
    2019, 0(2):  137-140.  doi:10.13474/j.cnki.11-2246.2019.0060
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    The annotation of place names near national boundaries involves administrative place names, natural place names, historical place names, foreign place names, ethnic minority place names, etc. The annotation forms are various. Based on the study of the relevant regulations on the representation of place names on open maps in China, this paper proposes that the annotation of place names near the boundaries on open maps should not only consider the requirements of map compilation. More attention should be paid to the political orientation of place names, their historical origin and the translation criteria of minority languages.

    Experimental study on accuracy of mapping large scale topographic map by knapsack mobile laser scanning system
    XIE Hongquan, CHEN Yuetao, ZHAO Fang, TIAN Dongwei, LU Xia
    2019, 0(2):  141-143,156.  doi:10.13474/j.cnki.11-2246.2019.0061
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    The application of the piggyback mobile laser scanning system in the mapping of large scale topographic maps is critical to the scanning accuracy. Using the Leica Pegasus Backpack to scan the survey and mapping geographic information building of Suzhou Industrial Park, use Inertial Explorer, Infinity, AoTumatic Processing to preprocess the point cloud data, use RealWorks to extract feature points, and draw the feature points in the MicroStation V8 joint diagram as 1:500 topographic maps. After superimposing the 1:500 topographic map drawn by the traditional method, it is found that the two topographic maps have a good coincidence. After the accuracy analysis of the ground object detection point, the error in the point is 0.026 m, and the error in the elevation is 0.041 m. The results show that Leica Pegasus Backpack meets the accuracy requirements of 1:500 topographic map measurement.

    Teaching research and practice of GNSS technology and applications in surveying courses
    WANG Guangxing, LI Wei, ZHANG Shaocheng, DING Kaihua
    2019, 0(2):  144-146,160.  doi:10.13474/j.cnki.11-2246.2019.0062
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    Surveying is the fundamental technical course for many non-geomatics specialties, and GNSS is one of the most important contents in the course. Based on the teaching practice, this paper indicated the existing problems in the teaching of GNSS in surveying courses, such as the outdated textbooks and inaccurate information in the networks. Tentative solutions, such as extending the teaching contents, combining the teaching with scientific research, making full of new media, and well designing the classes, were proposed. Better teaching results were obtained after these reforming strategies were applied.

    Experimental teaching reform and practice exploration with the emerging engineering education concept
    CAI Jianhong, HUO Liang, ZHU Ling
    2019, 0(2):  147-152.  doi:10.13474/j.cnki.11-2246.2019.0063
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    In recent years, in order to adapt to the cultivation of innovative talents, the excellent plan has opened a new teaching mode. Based on the Emerging Engineering concept, in order to carry out the teaching of the experiment course better, taking 3D modeling using 3ds Max software as an example, the teaching practice exploration is carried out from the aspects of the course content arrangement, the teaching method, the estimation mechanism and so on. Based on the practical experience of experiment course of the application software, this paper pays attention to the cultivation of the students' team cooperation and communication, practical ability, the creative ability, the ability to learn new things in a multichannel and fast way, and the ability to solve complex problems appling multi-disciplinary knowledge and cooperation. All these provide reference for improving practical teaching, so as to better adapt to the cultivation of innovative talents with the emerging engineering concept.
    Application of high precision image scanner in slope stability analysis
    YANG Maowei
    2019, 0(2):  153-156.  doi:10.13474/j.cnki.11-2246.2019.0064
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    The high and steep slope of loose accumulation body is very unstable and has great potential safety hazard. It is necessary to evaluate the slope stability scientifically and accurately. This paper uses the high precision imaging scanner to scan the high and steep slope of the whole area, at the same time, it accesses a variety of ground slag heap parameters, the evaluation of the slope and the slag heap parameters such as the water catchment area of the area. This paper provides a detailed and accurate data for slope stability analysis, and greatly improvs the efficiency and the accuracy of the evaluation.
    Discussion on the development mode of state-owned surveying enterprise informationization
    ZHAO Lifeng
    2019, 0(2):  157-160.  doi:10.13474/j.cnki.11-2246.2019.0065
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    Based on the industry characteristics of state-operated survey enterprise information development, this paper analyzes the status and the existing problems of both survey production management and survey professional development informationization. Then the paper puts forward the pattern of survey industry information in the era of Internet+ and big data information. Through the use of computer and internet technology for survey production methods, production processes, data standards and results management, the purpose is to achieve the modernization of survey production, the specialization of survey results, the standardization of data formats, integration of information sharing, standardization of service processes, integration of business and finance and intelligent application of survey information and so on. Based on the development of survey technology, the survey data play an important role in the construction of the smart city. The massive data derived from it and the Internet of things data, BIM information data and urban transport data will be utilized, to realize the upgrading and transformation of the survey and design industry.
    An attempt of building 3D modeling based on UAV tilt photography
    REN Cheng, GAO Limin, FENG Yaolou, ZHANG Wang
    2019, 0(2):  161-164.  doi:10.13474/j.cnki.11-2246.2019.0066
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    In recent years, with the constantly improve of the level of science and technology, aerospace technology, network communication technology, computer technology and information technology rapid develop, the getting ability of remote sensing data has been effectively promoted, formed by the source (multiple platforms, multiple perspectives, multiple sensors), high resolution (spectrum, time, space, radiation) as the characteristics of high efficiency, diversity, rapid empty world integration of the data acquisition method. Taking Topcon falcon 8 eight-rotor UAV platform as an example, this paper analyzes the low-altitude photogrammetry data obtained by the platform, and uses Smart3D software to model buildings, so as to provide strong technical support for the three-dimensional system construction of smart city.