Table of Content

25 April 2019, Volume 0 Issue 4

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Navigation satellite clock bias prediction based on grey model improved by least absolute deviations

YU Ye, HUANG Mo, WANG Xiaoqing, HU Rui

2019, 0(4):  1-6.  doi:10.13474/j.cnki.11-2246.2019.0102

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In order to overcome the shortcomings of satellite clock bias(SCB) forecasting accuracy based on the grey model(GM(1,1)) parameters of least squares estimation in the case of large SCB fluctuations, this paper uses the least absolute deviations(LAD) to improve the GM(1,1). During the modeling process, the principle of minimizing the absolute sum of errors is used as the optimization principle. Aiming at the non-differentiable characteristics of the objective function, the linear programming method is used to estimate the model parameters of the GM (1, 1). In addition, the improved forecasting model is applied to the forecast of the SCB when the SCB fluctuates greatly, and the forecast results are compared with the results predicted by GM (1, 1).The results show that the prediction results of the GM (1, 1)-LAD are significantly improved compared with the GM (1, 1) in the case of large fluctuations in the SCB, which provides a new idea for high-precision SCB prediction.

Accuracy analysis of single satellite timing of BeiDou Navigation Satellite System

ZHANG Dazhong, ZHENG Zuoya, LIU Yi, GU Shouzhou, BI Jinzhong, LI Jie, ZHANG Tao

2019, 0(4):  7-10.  doi:10.13474/j.cnki.11-2246.2019.0103

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In order to study the single-star timing accuracy of the BeiDou Navigation Satellite System, based on the GPS single-star timing principle, combined with the characteristics of the BeiDou satellite multi-type constellation, this paper compiled the BDS single-star timing software. Experiments were carried out using iGMAS station data. After the original data was monitored and the anomaly information was removed, the timing results were compared with the CGS clock difference file of China Academy of Surveying and Mapping, and the BDS different orbit satellites were analyzed. BDS single-star timing accuracy under GEO/IGSO/MEO). The results show that the timing accuracy of the GEO satellite is 27.39 ns, the timing accuracy of the IGSO satellite is 18.37 ns, and the timing accuracy of the MEO satellite is 18.62 ns.

Research of sub-meter GNSS differential location cloud service based on CORS

HAO Jianming, CHU Bin, AO Minsi, GU Souzhou

2019, 0(4):  11-16,25.  doi:10.13474/j.cnki.11-2246.2019.0104

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In order to meet the demand of large-scale high-precision location services in the field of GNSS mass applications, this paper proposes a CORS-based construction method for differentiated positioning cloud service based on CORS. It solves the problems of traditional CORS service such as large data base security risks and limited number of concurrent user accesses by using the virtual grid to generate the form of correction and designing a cloud service model of solution server and business server separating. It also provides applications and services to users and developers using APIs and SDKs, reducing the threshold for high-precision location services. At the same time, relying on the research results of this paper, based on the Hunan location service platform (HNCORS), designs and implements CORS-based GNSS differentiated positioning cloud service architecture. And to packet loss rate, external meet the accuracy, high concurrent access as an indicator for testing, the results show that the cloud service architecture designed in this paper has good accuracy, stability and reliability, and has good application prospect in high-precision location service applications. It can also be a high-precision location service cloud platform of other provincial CORS networks construction to provide technical reference.

Implementation of seamless switching communication model for BDS high precision CORS cross-network service

ZHANG Jingjing, HU Ke, CHEN Xianchun, LI Peng, ZHANG Xi, SHI Xin

2019, 0(4):  17-20,31.  doi:10.13474/j.cnki.11-2246.2019.0105

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At present, the BDS CORS service systems in different provinces and cities in China operate independently of each other. The accounts of the service system in different provinces can't be universally used, which affects the social application scope of BDS high-precision location service to a certain extent. To solve this problem, this paper proposes a virtual communication medium based on mobile communication technology. Based on the virtual communication medium, the communication model of CORS cross-network service seamlessly switches can enable users to seamlessly switch between different provinces and real-time access to inter-provincial BDS high-precision services data. This method does not change the current service processes of various provinces and cities.And the user can realize the seamless switching and use the CORS service in different provinces and cities without re-registering the account. After testing,the average time of cross-province switching and obtaining high-precision positioning data is 9.029 s by using this method.This method can be applied to multi-provincial and inter-network services and the national "BDS location service one network" construction.

Power line classification from airborne LiDAR data via multi-scale neighborhood features

WANG Yanjun, LI Kai, LU Lijuan

2019, 0(4):  21-25.  doi:10.13474/j.cnki.11-2246.2019.0106

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With the rapid development of 3D accurate measurement technology of airborne LiDAR, automatic extraction of power lines from airborne laser point clouds has become an important topic in point cloud data processing and transmission line management. In this paper, we present an automated and versatile framework for power line classification, which consists of four steps:power line candidate point filtering, multi-scale neighborhood type selection, feature extraction based on geospatial structure, and SVM classification. To comprehensively evaluate the proposed algorithm, we calculate each point's feature based on eight levels of scales. Two datasets demonstrate that classification results reach up to 97%, 94%, and 93% in terms of precision rate, recall rate and overall quality. The whole processing time also decreases from 366 s, 256 s to 274 s, 160 s, respectively. Experimental results show that this method can achieve high-precision classification of power lines in complex urban environment.

Analysis on point cloud of building facade segmentation algorithms based on 3D laser scanning data

HE Yifeng, HU Rong, ZOU Jingui

2019, 0(4):  26-31.  doi:10.13474/j.cnki.11-2246.2019.0107

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The application of 3D laser scanning technology is becoming more and more widespread in current society. However, due to the large amount of point cloud data, how to reconstruct and identify a large number of point cloud data quickly and efficiently is the key to solve the problem. The point cloud segmentation technology can separate the feature information in the facade point cloud from the background point cloud, providing important technical support for the extraction and identification of feature information. In this paper, a variety of point cloud segmentation algorithms are programmed to segment the facades of buildings, and the segmentation accuracy and applicable range of different algorithms are analyzed in detail.

Remote sensing image classification algorithm based on mRMR selection and IFCM clustering

HUANG Lei, XIANG Zejun, CHU Heng

2019, 0(4):  32-37.  doi:10.13474/j.cnki.11-2246.2019.0108

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In order to solve the problem of poor classification precision caused by high correlation redundancy between features of high-resolution image and poor robustness of FCM clustering, an image classification algorithm based on mRMR selection and IFCM clustering is proposed. First, the image segmentation is carried out based on the object confidence index (OC), then the feature selection is realized by mRMR algorithm to solve the feature redundancy problem. The extracted feature is put in classifier and final classification result is clustered by IFCM algorithm. Comparison of experimental results show that the proposed algorithm can reduce feature correlation and redundancy and effectively improve image classification accuracy.

Tree species classification of high resolution image combining with object-oriented and deep feature

TENG Wenxiu, WANG Ni, SHI Huihui, XU Zhenyu

2019, 0(4):  38-42.  doi:10.13474/j.cnki.11-2246.2019.0109

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A tree species classification of high resolution image combining with object-oriented and deep feature is proposed to overcome the problem that traditional manual extraction features need professional knowledge and difficult to extract high quality features.In order to obtain the precise boundary of tree species, the method firstly uses multiscale segmentation technology to segment the whole remote sensing image, and selects the training samples as the input of the deep convolution neural network.In order to avoid over-fitting caused by a small number of samples, transfer learning method is used to initialize the deep convolution neural network with the parameters of VGG16 model trained on ImageNet. Using global average pooling compression parameters, a 1024 nodes fully connected layer and 7 nodes Softmax classifier are added at the end of the network. The network is trained by back propagation and Adam optimization algorithm.Finally, the whole remote sensing image is classified and the tree thematic map is generated. The test site is located in the Huangfu Mountain National Forest Park in Anhui province.QuickBird high resolution image is the data source.The results show that the overall accuracy and Kappa coefficient of this method are 78.98% and 0.6850 respectively, which can ensure the accuracy of tree species and achieve end-to-end tree species classification.

Improved binary cuckoo search algorithm for band selection in hyperspectral image

SONG Guangqin, DU Zhengshun, HE Zhi

2019, 0(4):  43-48.  doi:10.13474/j.cnki.11-2246.2019.0110

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Spectral band selection serves as an important part in hyperspectral image classification. In this paper, an improved binary cuckoo search algorithm for band selection in hyperspectral image is proposed. Binary cuckoo search algorithm is improved by these two ways, one of which is that we update the nests of offspring by using a binary encoding algorithm. Another one is that the found nests are updated based on the crossover mode of genetic algorithm. The improved binary cuckoo search algorithm achieves the goal of dimensionality reduction of hyperspectral image by finding the bands with low correlation and the vital function in the image. The improved binary cuckoo algorithm is applied to PaviaU datasets and AVIRIS datasets, compared with binary cuckoo algorithm, binary particle swarm algorithm, minimum redundancy maximum correlation algorithm, relief algorithm. The results show that the improved binary cuckoo search algorithm is more efficient in the band selection, and the selected bands are more representative and can improve the precision of the image classification.

Research and application of a new method for measuring main girder of a large span cable-stayed bridge

GU Xuanlong, LIU Chenglong, LI Lei, SHEN Luming, JIANG Tao, YANG Xuefeng

2019, 0(4):  49-53,59.  doi:10.13474/j.cnki.11-2246.2019.0111

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Large span cable-stayed bridges have small structural stiffness and large deformation. In order to ensure the naturally closure of each segment on the main girders, the plane position and vertical alignment must be quickly and accurately located. Distinguished from the traditional method of polar coordinates measuring the girder plane, we propose a free station method used to measure the plane of girder. At the same time, different from the traditional level measurement, the method of measuring the girder vertical line using the total station indirect height difference is proposed. The paper first introduces the measurement principle of two new methods, and finally demonstrates the feasibility and practicability of the new method through a engineering example,which can greatly improve the measurement efficiency. It can provide a reference for the monitoring of other large span girders.

Design and implementation of system estimating carbon emission induced by land use/cover change

YANG Xuhong, JIN Xiaobin, LIU Jing, GU Zhengming, ZHOU Yinkang

2019, 0(4):  54-59.  doi:10.13474/j.cnki.11-2246.2019.0112

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Due to the tedious parameter setting, complex calculating process and complicated logic structure, the model and method to calculate the carbon emission induced by land use/cover change have been limited to widely apply in the domestic research field of carbon budget estimation. Selecting the fundamental principles of bookkeeping model as the core algorithm, this research has constructed a comprehensive system including four core functions which can effectively estimate the carbon emission induced by land reclamation, abandoned farmland, forest harvest and recover. The comprehensive system can parallelly calculate the directive carbon emission of soil and vegetation disturbing from the human land use in many regions which can be the administrative districts or geographical units. It is improved the effect of system due to the concise interface, few parameters and convenient operation.

Evaluation for typical compression method of trajectory data

LIANG Ming, CHEN Wenjing, DUAN Ping, LI Jia

2019, 0(4):  60-64,70.  doi:10.13474/j.cnki.11-2246.2019.0113

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One of the key bottlenecks in the big data of trajectories is the massive data size of the trajectory data. Therefore, the compression of trajectory data is the important field of the trajectory big data research. Existing trajectory compression algorithms emphasize the maintenance of the single dimensional space-time feature of the trajectory data, but lack the study of the impact of compression algorithm on the multi-dimensional space-time feature. In this paper, multi-dimensional space-time characteristics of trajectory data such as area error, distance error, direction error, speed error, compression rate and compression speed of MBR are selected for evaluation, and typical trajectory compression methods are evaluated from three levels of geometric features, motion features and compression efficiency of the trajectory. At the same time, in order to systematically observe the change of trajectory time and space characteristics of trajectory compression algorithm on different compression scales, this paper adopts the evaluation method of multiple scale compression results.Comprehensive research results show that the overall effect on considering the trajectory feature compression algorithms such as TD_TR algorithm to track the overall characteristics of time and space to keep the good, and the effect of different compression algorithms on the space-time characteristics of overall consistency with scale change.

Metric description of spatial topological relations in moving objects

LI Pengpeng, LIU Jiping, LUO An, ZHANG Yuting

2019, 0(4):  65-70.  doi:10.13474/j.cnki.11-2246.2019.0114

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Aiming at the deficiency of the traditional 9-intersection model to express and quantify the spatial topological relations of moving objects, a method of quantitative description of metric parameters is proposed based on the idea of gridization. Firstly, the moving object and the reference object are grid-processed and divided into fixed-size grid arrays; then the 9-intersection model is used to determine the formal description of the topological relations among the spatial objects; finally, the internal components, boundary components, and external components are introduced to describe the spatial topological relations of the moving objects. Experiments show that this method is simple and intuitive to calculate and can more effectively measure the topological relations between moving objects.

Improvernent of the method of GNSS retransmission deception interference mode

HE Ting

2019, 0(4):  71-74,83.  doi:10.13474/j.cnki.11-2246.2019.0115

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In order to solve the problem of clock jumping of the target receiver in the GNSS retransmission deception interference mode, which will result in the failure of jamming, a modified method based on jammer array is proposed in this paper. The jammer array could be set as regular hexagon, and the benefit is that wherever the target is, there will be one optimal jammer which can interfere with the target effectively. The simulation study is carried out to make sure the optimal space between neighbouring jammers. The conclusion shows that the optimal space mentioned above is 17 km. If the condition is fulfilled, the jamming from the jammer array will not lead to any clock jumping of the target receiver and the problem that the interference is easy to be identified is solved certainly.

Calculation three-dimensional co-seismic deformation of the 2017 Iran-Iraq earthquake by multi-angle InSAR data

HAN Ming, ZHANG Yongzhi, CHENG Dong, YIN Peng

2019, 0(4):  75-78,129.  doi:10.13474/j.cnki.11-2246.2019.0116

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The 2017 Iran-Iraq earthquake is the largest earthquake in zagros mountains since 1900. In order to study the coseismic deformation field caused by the earthquake, two-pass differential DInSAR processing is carried out using three pairs of Sentinel-1A elevation track data covering the same area, and the three-dimensional coseismic deformation field of the study area is reconstructed by direct solution algorithm. The experiment shows that the elevation track line of sight of the three perspectives is basically consistent with the settlement trend. The reconstruction of 3D deformation field can be realized by combining the observation results from multiple perspectives. According to the characteristics of surface line of sight and three-dimensional coseismic deformation and geological structure background, it is speculated that the seismogenic fault is likely to be Zagros piedmont fault.

High resolution remote sensing image building extraction in dense urban areas

FANG Xin, CHEN Shanxiong

2019, 0(4):  79-83.  doi:10.13474/j.cnki.11-2246.2019.0117

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Buildings are an important target of the monitoring of geographical conditions. The rapid and accurate extraction of urban buildings can bring great economic value. Many people have done a lot of work in the building extraction of the city area. On the basis of predecessors' research and aiming at the problems of existing extraction method, this paper proposes an object-based automatic building extraction process in dense urban areas. First, high-resolution remote sensing images are used to get the shadow and quasi building extraction results. Then, build a filter by the spatial location relationship of the shadows and the crude building extraction results to filter the suspected building area. Finally, get a precise building outline through the graph cut algorithm. For algorithm verification experiments, the accurate detection results can be obtained by using two QuickBird images in Wuhan. This algorithm can be applied to the building detections in dense urban areas.

Analysis of influence of ground settlement on gravity anomaly in urban Kunming based on InSAR technique

ZHANG Yong, LIU Dong, WANG Zhimin, MU Baosheng, WANG Youkun

2019, 0(4):  84-86.  doi:10.13474/j.cnki.11-2246.2019.0118

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The principle of gravity reduction is used to deduce the effect of elevation change on the gravity observations, and the correction of gravity Bouguer anomalies, spatial corrections, and interlayer corrections due to elevation changes are calculated. Combining the years of InSAR image data of Kunming city, this paper calculates the amount of land subsidence change in the urban area. In the process of gravity data, combines InSAR technology to obtains the surface subsidence variation, obtains the accurate gravity value due to the change of geological density, and then calculates the change of the part. The impact of gravity anomalies on the Kunming area, combined with the application of gravity anomalies in earthquakes, illustrates the importance of improving the accuracy of gravity measurements in geological hazards.

The impact of urban local climate zone on land surface temperature: a case study of Dalian

JIN Shanhe, ZHANG Yuqing, YANG Jun

2019, 0(4):  87-90.  doi:10.13474/j.cnki.11-2246.2019.0119

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Based on Dalian urban building data, SPOT 5 and Landsat 8 remote sensing data, using local climatic zone classification and land surface temperature inversion method to study the regional zoning types and characteristics of Dalian, and the impact of different local climatic zones on urban surface temperature. The research results show that the height of building types in Dalian are mainly low-rise buildings, multi-storey buildings and medium-rise buildings. The building density is medium density and high density. The Ganjingzi District is distributed with a large number of forest green areas, and the Zhongshan District is rich in park green space. The surface temperature is generally high, and the space is east to west and low. The surface temperature of more than half of the area reach 28~31℃, and the surface temperature of more than 1% is greater than 38℃, indicating that the region has extreme high temperature. At the same building height, the higher the density of the building area, the higher the surface temperature; the same density building, the multi-storey building coverage area has a higher surface temperature. The surface temperature of forest green space is the lowest, the surface temperature of park green space and community green space is almost the same, and the surface temperature of the auxiliary green land is the highest.

Mapping and research of 1: 10 000 topographic map in desert area based on airborne LiDAR technology: an example for Alxa, Inner Mongolia

WANG Zhiming, LI Suole

2019, 0(4):  91-95.  doi:10.13474/j.cnki.11-2246.2019.0120

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In recent years, airborne LiDAR technology has been applied to power, forestry, surveying and mapping and so on. Compared with optical image, LiDAR point cloud data has unique advantages in surveying and mapping. This paper attempts to use airborne LiDAR technology to survey and map 1:10 000 scale 3D (DLG, DEM, DOM) products, summarizes the technological process and precision analysis method of airborne LiDAR 3D products, and selects desert areas as experimental areas to verify the feasibility of this technology in desert areas to produce 3D products. The method can satisfy the requirement of 1:10 000 scale 3D basic data production in desert area, and has the advantages of small outdoor workload, high automation, fast mapping, high elevation accuracy, and small environmental impact. At the same time, the method is also summarized. This method provides a useful reference for the acquisition of 3D basic surveying and mapping data in desert areas.

Calibration method of line-scan camera based on projection transformation

SU Lin, WU Zhaocong, YAN Zhao, WANG Peng

2019, 0(4):  96-98,102.  doi:10.13474/j.cnki.11-2246.2019.0121

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In view of the difficulty of obtaining the calibrated data of the line-scan camera and the instability of the model solution, a calibration method based on the projection transformation is proposed. First, a new imaging model of linear rotation scanning camera is constructed. The model can be projected into a frame image based on the parameters of the rotating platform of the camera and the position relationship between the image plane and the tangent plane. Then, according to the imaging model constructed, the direct linear transformation method and nonlinear optimization method are used for camera calibration and parameter optimization. The experimental results show that the method is simple and feasible with high accuracy.

Landslide monitoring by merging ground laser point cloud and aerial image

WANG Qingguo, ZHAO Hai, LI Jianping

2019, 0(4):  99-102.  doi:10.13474/j.cnki.11-2246.2019.0122

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Aiming at the actual needs of landslide monitoring for a hydroelectric power station in Yunnan, this paper proposes a landslide monitoring method that merges ground laser point cloud data and aerial imagery. Firstly, data registration is used to realize the fusion and integration of ground laser point cloud and aerial image. Then, through data noise removing and surface model reconstruction, the monitoring data benchmark is established. Finally, the deformation law of the landslide area is studied by the overall deformation analysis based on the surface model and the sampling analysis based on the profile. Based on the five monitoring data that have been obtained, it shows that the monitoring method proposed in this paper has high monitoring accuracy and good applicability.

Hybrid-model based camera distortion iterative calibration method

WANG Jiali, WANG Weijie, MA Zhenling

2019, 0(4):  103-106.  doi:10.13474/j.cnki.11-2246.2019.0123

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Rigorous camera calibration is fundamental to perform accurate measurement and 3D reconstruction. This paper analyses the calibration models for three types of planimetric distortions namely radial distortion, decentering distortion and the orthogonality and affinity (linear) distortion. These distortions are simulated and introduced to ideal images in order to conduct experimental tests. The results indicate that no matter what kind of distortion the images have, the physical model which takes into account all three type of distortion performs best, however, the experimental results also indicate that the existing physical models cannot completely eliminate the image distortion. Therefore, a mathematical calibration model (Chebyshev polynomial) is introduced, and an iterative calibration approach is adapted to attempt to further improve the calibration results. The hybrid iterative calibration approach chooses the calibration model during iterations alternatively between a physical model and a mathematical model. Calibration results from both simulated images and real images (GoPro camera) demonstrate that the use of the proposed hybrid iterative calibration approach can further reduce the distortion.

Content and expression of provincial national geographic conditions census communique

CHENG Xiong, LIU Mingchuan, XIAO Ying, LI Zhao

2019, 0(4):  107-110.  doi:10.13474/j.cnki.11-2246.2019.0124

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The provincial national geographical conditions communique that has already been released in China has been linked to the national communique in its content.Using a combination of text, forms, and small-scale thematic maps, the basic geographic situation is described objectively and generally from the perspective of the province.Some provinces have also refined the important geographical conditions to their jurisdiction,but the content is not rich enough. Taking Wuhan's first national geographic conditions census communique design as an example, this article discusses the content and expression design of provincial communique,and guides governments at all levels, departments and the public to better understand and use the results of national geographic conditions census.

Updating method of graph-database integration for geographic information

ZHOU Xiaodong, MENG Nina, XIE Peng, HE Liesong

2019, 0(4):  111-114.  doi:10.13474/j.cnki.11-2246.2019.0125

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There is difference and relativity between the updating mode of map and DLG. Based on the research of DLG incremental update and integrated management of map and DLG, a graph-database integration updating method for geographic is proposed. The spatial information of geometry and attribute and the symbolic graphic information are organized in the unit of geographic entity. With map presentation of DLG incremental information, the incremental information of symbolic graphic information is obtained. Real-life data were used to verify the effectiveness and the advantages of easy realization by computer, high efficiency and scalability, and being suitable for the integrated updating of maps and DLG.

An entity construction method of urban roads considering geometric connectivity and name consistency

LI Yuanfu, SUN Qun, JI Xiaolin, ZHOU Zhao, LÜ Zheng

2019, 0(4):  115-118.  doi:10.13474/j.cnki.11-2246.2019.0126

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This paper presents an entity construction method that considers both geometric connectivity and name consistency. Firstly, the entity construction principle of urban roads is described. Secondly, the normalized geometric connectivity degree measurement method based on inverse proportion function and the name matching degree measurement method based on semantic segmentation are proposed. Finally, through intersection extraction, comprehensive matching degree calculation, segment matching, segment connection and lane borrowing processing, a complete process of urban road entity construction is realized. The accuracy of this method is verified by a concrete construction experiment taking the main urban area of Zhengzhou as the experimental area. The experimental results show that the overall accuracy of the entity matching algorithm for road segment is 99.89%.

Research on real 3D modeling supported by cluster technology

HE Yanru, XU Jinghai, QIN Jun

2019, 0(4):  119-124.  doi:10.13474/j.cnki.11-2246.2019.0127

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The emergence of computer cluster technology provides a solution to the shortage of computing resources encountered in 3D automatic modeling of tilted photogrammetry. This paper discusses two application patterns of cluster in 3D modeling:cluster based on physical parallel computing and cluster based on logic parallel computing. The process of 3D modeling of real scene in ContextCapture under the cluster mode of logical parallel computing is expounded. Five principles of subdivision in this cluster are proposed:the principle of the starting and landing points, the principle of flying height, the principle of building density/vegetation density, the principle of maximum calculation and the principle of line angle. And the accuracy of the sub region is effectively controlled. Finally, this paper uses a number of common PC machines in the laboratory to achieve a three-dimensional cluster modeling in a certain area. The results show that the method automatically establishes the model accuracy to meet the requirement of the survey area, and can effectively speed up the automation modeling speed and reduce the production cost.

Exploration on the unified registration of natural resources in the service of mapping geographic information in the new age: a case study of Beijing natural resources unified rights registration

SUN Jing

2019, 0(4):  125-129.  doi:10.13474/j.cnki.11-2246.2019.0128

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In the new era, natural resources have become an important foundation to support the construction of ecological civilization, an important part of the construction of property rights system of natural resources, and a new field of social management and economic construction of geographic information services for surveying and mapping. From the point of view of surveying and mapping geographic information service, based on natural resources data collection, technological process optimization, integrated information platform construction and other stages, this paper discusses the technical support role of surveying and mapping geographic information technology in the unified right registration of natural resources.

Construction of unmanned marine surveying and mapping technology system

ZHOU Li, ZHANG Yang, ZHANG Yi, FU Dandan, CHEN Chen, WEI Zheng, FENG Junjun, LIU Zefeng

2019, 0(4):  130-133.  doi:10.13474/j.cnki.11-2246.2019.0129

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With the rapid development of unmanned technology, the era of unmanned mapping is coming. This paper analyzes the technical characteristics of the unmanned era and the development opportunities of marine surveying and mapping. It discusses the new concept of unmanned ocean surveying and mapping, constructs the unmanned ocean surveying and mapping technology system and discusses the key technologies of unmanned ocean surveying and mapping technology. It also prospects the development trend of unmanned ocean surveying and mapping technology and its application prospects in marine economy and sustainable marine development.

Design of vehicle measurement system into teaching practice

YAO Lianbi, ZHANG Shaohua, YANG Pengyu, ZHAO Ziliang

2019, 0(4):  134-137.  doi:10.13474/j.cnki.11-2246.2019.0130

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In view of the development of surveying and mapping science from traditional surveying and mapping to digital surveying and mapping, and then to the informatization surveying and mapping,this paper analyzed some deficiencies in current surveying teaching mode, and put forward the introduction of new technology of vehicle measurement system into undergraduate teaching. This paper analyzed the frontier and feasibility of the study of vehicle measurement system in the classroom, and made the modular design of course and experiment. The results show that the new products of surveying and mapping could arouse students' interest and innovation ability, improve their professional skills and conform to the modernization of surveying and mapping education.

Mode innovation and quality guarantee for training compound innovative and knowledge service talents of surveying and mapping in transition period

KE Fuyang, ZHAO Xianfu, DING Haiyong, SUN Jingling, ZHU Shanyou, MIAO Qilong

2019, 0(4):  138-142.  doi:10.13474/j.cnki.11-2246.2019.0131

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The problems existing in the current training of surveying and mapping engineering professionals have been analyzed and shown. To meet the new requirements of surveying and mapping 4.0 and intelligent surveying and mapping for surveying and mapping engineering professionals, School of Remote Sensing and Mapping Engineering of Nanjing University of Information Science and Technology relies on its advantages and characteristics to carry out a series of training innovations and practices in the following aspects:training scheme, course system, teaching means and modes, quality evaluation method and engineering training. A closed-loop quality assurance system for personnel training has been constructed. School of Remote Sensing and Mapping Engineering of Nanjing University of Information Science and Technology has acquired remarkable effectiveness and social reputation of mapping and surveying personnel training by the innovation mode and closed-loop quality assurance system, which will provide an important reference in the compound innovation and knowledge service-oriented senior personnel training of Surveying and Mapping Engineering for other universities.

Thinking about curriculum teaching of Digital Photogrammetry and exploration of the basic practice method

XU Zhihua, CUI Ximin, YANG Keming, YUAN Debao, SUN Wenbin

2019, 0(4):  143-147.  doi:10.13474/j.cnki.11-2246.2019.0132

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In recent years, with the increasingly intersection of computer vision and digital photogrammetry, high-resolution image acquisition platforms such as unmanned aerial vehicles, mobile measuring vehicles have been rapidly developed. As a result, new challenges are posed for the curriculum teaching and basic practice of digital photogrammetry. In This paper, we first analyze the main problems in the curriculum teaching of digital photogrammetry and provide some feasible reform schemes. Then, we introduce a framework of using software Agisoft PhotoScan and AcrGIS for basic practice of digital photogrammetry. Finally, we verify the effectiveness of the basic practice framework by taking the drone images as an example.

Reform of GIS professional training mode driven by academic competitions

CHENG Jiehai, YUAN Zhanliang, JING Haitao, XUE Huazhu, WANG Huilian, LI Wei, WANG Li, HE Shi

2019, 0(4):  148-151.  doi:10.13474/j.cnki.11-2246.2019.0133

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Under the background of the great development of geographic information industry, this paper analyzes the existing problems in the cultivation of GIS professionals. Combining with the reality of geographic information science in Henan Polytechnic University, and taking academic competitions as the driving factors, the paper reforms the talent training mode of GIS professionals from two aspects:the setting of "ladder" curriculum system and the construction of "sponge" student interest group. And the practical effect of the reform is elaborated from four aspects, such as academic competition results, graduates'employment, postgraduate entrance examination and international exchange. The studies can provide references for colleges and universities to train GIS professionals to meet the needs of the industry.

Study on the volume of felled trees based on 3D laser scanning system

ZHANG Minxia, ZHANG Huijuan, GAO Ruijin, WANG Rui

2019, 0(4):  152-154.  doi:10.13474/j.cnki.11-2246.2019.0134

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Using the 3D laser scanning system to obtain the overall point cloud data of felled trees. Using the application of point cloud micro-product filling to calculate the volume of felled trees and comparing the results with the volumes that are calculated according to the felled treesquadrature formula. The result shows that the data precision and measure efficiency are both higher using the laser scanner, which can meet the requirements of forestry survey accuracy, and provide technical support for the rapid and efficient measure of the cased involved felled trees.

Experiment and analysis of high-precision RTK positioning with the Leica GS18

WU Jicang, LI Yuting

2019, 0(4):  155-158.  doi:10.13474/j.cnki.11-2246.2019.0135

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Nowadays, the rapid development of sensor fusion techniques in GNSS, and IMU is offering a great opportunity to high-precision RTK positioning. The conventional tilt compensation solutions mostly use magnetmeter measurements and INS, which are sensitive to magnetic disturbances and need on-site calibrations. Moreover, the tilt compensation range is often limited to 15°. To avoid the disadvantages mentioned above, the tilt compensation solution of Leica GS18 uses IMU measurements from industrial-grade MEMS. The positioning accuracies of the Leica GS18 at large tilt angles and in difficult environments are tested by the experiments in this paper. The result indicates that the centimeter-level precision is still achievable even in hidden environments, the tilt compensation is reasonably acquired by the Leica GS18.

Data processing and acquisition of planning and acceptance survey based on 3D laser scanning technology

WANG Fen, XU Bingqian, HAO Dan

2019, 0(4):  159-161.  doi:10.13474/j.cnki.11-2246.2019.0136

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Three-dimensional laser scanning technology can quickly acquire high-precision and high-density points cloud data, what's more, it can also copy the proposed acceptance of the buildings and their surrounding environment to the computer almost completely without error. And it is an ideal method for planning and acceptance measurement, especially for complex buildings planning acceptance measurement. However, its data processing has always been a bottleneck affecting or even restricting its application. This paper briefly described the main points of planning acceptance measurement and the preliminary processing flow of 3D laser scanning points cloud data. In view of the different requirements for making various kinds of plans acceptance measurement maps, the working ideas and characteristics of each method for making the results maps by direct line-taking, slicing and projection were put forward. And in view of the different requirements of making various drawings of planning acceptance measurement, this paper put forward the working ideas and characteristics of each method of making the results drawings by direct line-taking, slicing, projection and so on. However, it is necessary to research and solve the problem of data processing of massive point clouds and obtaining surveying results maps according to the characteristics of acceptance measurement.

Discussion on design and application of the 2D and 3D integrated storage of real estate spatial data

CHEN Zepeng, WAN Baolin, LI Qing

2019, 0(4):  162-164.  doi:10.13474/j.cnki.11-2246.2019.0137

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This study analyzes real estate geospatial data and ArcGIS's GeoDatabase data model, designs rules and methods for unified storage of real estate geospatial data results and 2D&3D data. Thereby it can provide data support for the application of the 2D and 3D system of real estate registration.