Table of Content

25 November 2017, Volume 0 Issue 11

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GPS Multipath Correction Algorithm Based on CEEMD-Wavelet-SavGol Model

ZHAO Long, GAO Jingxiang, LI Zengke, WANG Jian

2017, 0(11):  1-5.  doi:10.13474/j.cnki.11-2246.2017.0337

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A new algorithm based on CEEMD-Wavelet-SavGol model was proposed in view of the problem that the EMD algorithm has the mode mixing effect and the Wavelet denoising has some limitations. In order to fully extract the useful information from the high-frequency component and low-frequency components, the proposed algorithm could decompose signal using complete empirical mode decomposition(CEEMD) to get a series of intrinsic mode functions(IMF) from high to low frequency. Then the scale could be distinguished according to the mean of standardized accumulated modes(MSAM). And then the low-frequency and high-frequency components were denoised by wavelet and SavGol filter. The denoised signal would be obtained after IMFs reconstruction. At last, the proposed model was applied to GPS multipath error extraction, and the validity of the new model was proved compared with Wavelet, EMD and CEEMD model.

Study on Kalman Filtering Time-lag Smoothing Method in Satellite Positioning

LIU Cheng, GUO Shuren, LI Fang

2017, 0(11):  6-10,26.  doi:10.13474/j.cnki.11-2246.2017.0338

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In order to improve the accuracy and performance of satellite navigation positioning,a method of Kalman filtering time-lag smoothing was introduced and discussed,and a Kalman filtering smoothing positioning model and its algorithm were built in this paper.Similar to classical Kalman filteing,the algorithm also has two kinds of equations-status system and measuring system,which could help to predict and update backward on the basis of follow-up epoch measured values and positioning results,thereby the overall positioning process can be smoothed again so that we can obtain the balance between positioning result tracking and smoothing performance.The paper analyzed and verified validity and feasibility of the method on the basis of GPS field experiment in various circumstances.Experiment results indicate that Kalman filtering time-lag smoothing positioning method can be adopted in various static and dynamic state navigation application field,which could make position results more smooth and accurate.The method has better anti-multipath and anti-interference performance, and it could also effectively improve positioning accuracy.

The Multi-system Combination PPP Computational Performance Analysis Based on the UofC Model

BU Jinwei, CHEN Yunbo, ZUO Xiaoqing, CHANG Jun, LI Xiaolong

2017, 0(11):  11-16.  doi:10.13474/j.cnki.11-2246.2017.0339

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In view of the GNSS system combination for the PPP positioning problem,we deduced the function model and stochastic model of the multi-system combination PPP based on the UofC model,and calculated different combination mode of PPP by using part of the data observed from IGS stations 30 d.The experimental analysis results showed that the GNSS multi-system combination PPP could shorten the convergence time by 30%~50% compared with the GPS system. For positioning accuracy,when the observation time was relatively short (e.g.,0.5 h),the GNSS multi-system combination PPP had better performance,(N,E) direction deviation and standard deviation could reach(0.3,0.3)cm(1.9,4.3)cm respectively,but in a short period of time,U direction accuracy was a bit poor because of the strong correlation of the troposphere parameters and the vertical direction. In addition,under the condition of the satellite altitude cut-off Angle was greater than 40°,single number visible satellite system deficiency leading to continuous cannot locate,but the combined system could still get a good positioning accuracy because it had more visible satellites,which had practical application value in the building concentration areas,mountains and the area where the satellite was seriously blocked.

Five Object-oriented Classification Methods Analysis Based on High-resolution Remote Sensing Image

LIN Hui, SHAO Congying, LI Haitao, GU Haiyan, WANG Lijuan

2017, 0(11):  17-21.  doi:10.13474/j.cnki.11-2246.2017.0340

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In view of the mainstream object-based classification method in remote sensing image processing using range is not clear, based on e-Cognition software, the standard data set is processed. Comprehensively considering the visual effects, overall accuracy and user accuracy, classification results and precision analysis of mainstream object-based classification are systematic analysis in the high resolution image. The experimental results show that there are mixed phenomena using different classification methods and the mixed objects are not exactly the same. In dealing with the same standard data set, the membership function has the highest accuracy but the slowest speed. The classification effect of Bayes is the worst, but the operation is simple. The classification speed of SVM, RF, DT are faster and have higher accuracy. Meanwhile SVM has obvious advantages in distinguishing objects with high similarity. In the selection of high resolution image classification method, we should fully consider the feature selection of classified images to select the appropriate classification method.

Change Monitoring of Snow-coverage Based on ALOS-PRISM Stereo Images

WANG Conghua, LIU Wei, DU Hejuan, LIN Zongjian

2017, 0(11):  22-26.  doi:10.13474/j.cnki.11-2246.2017.0341

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For the problem of snow cover land surface change monitoring, a new method was introduced taking Geladandong for instance. Using this method, the extraction of glacier DEM with ALOS-PRISM stereo-pair images was carried out, and snow-covered land surface change as well as volume change monitoring was applied with multi-temporal homology DEM images. Area variation of snow-covered land surface was obtained using ISODATA classing method based on rectified images by DEM images.Volume variation of glacier was obtained by area difference value and elevation difference value, which was derived from elevation-noted points in multi-temporal DEM images. Therefore, estimation of snow volume from 2009 to 2010 was implemented.Results showed that reduced snow volume was 19.728 3 km³ and area of snow cover was 349.691 km² from December 2009 to December 2010.A method for extracting glacier DEM was put forward with stereo-pair images, and as well as for calculating volume variation of glacier with multi-temporal homology DEM images.

Measurement of Point Cloud Data Segmentation Based on Euclidean Clustering Algorithm

CHEN Xiangyang, YANG Yang, XIANG Yunfei

2017, 0(11):  27-31,36.  doi:10.13474/j.cnki.11-2246.2017.0342

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Euclidean clustering algorithm is an important classification method of multivariate statistical analysis. It can be applied to the segmentation of point cloud in survey field. Euclidean clustering algorithm firstly calculates the Euclidean distance between two points. The points' distance which are less than a specified threshold are divided into a kind. Until all kinds of distance are greater than the specified threshold, it completes Euclidean clustering segmentation. Specific steps are as follows:① using Octree method set up topology structure of point cloud data; ② for each point conduct K-nearest neighbor search, calculating the Euclidean distance between point and K neighboring points, the minimum is regard as one kind; ③ set a certain threshold, the iterative calculation ② steps until all distances between the classes are greater than the specified threshold. Experiments show that Euclidean clustering algorithm is available to point cloud data obtained from different measuring means. It can successfuly segment point cloud data and the effect is good.

Classification of GF-2 Image Used by Multiple Classifiers Self-adaption Cascade Model

WANG Yao, YANG Huachao, WANG Guanghui, HUANG Jie, WANG Geng, LIU Xiao

2017, 0(11):  32-36.  doi:10.13474/j.cnki.11-2246.2017.0343

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Aiming at the shortcomings of traditional single classifier and the lacking that the existing multiple classifiers cannot adjust itself dynamically according to the characteristics of unknown sample, the classification method of high resolution remote sensing image based on the self-adaption cascade model of multiple classifiers is proposed. In this model, the optimal classifier and the whole optimal classifier are selected to dynamically assemble, making an self-adaption adjustment by performance of the sample which will be classified in this classifier, and the model can produce output category information. By GF-2 image on Hangzhou area classification test, the results show that the multiple classifiers self-adaption cascade model method has a higher classification accuracy compared to a single classifier.

Spaceborne InSAR Topographic Surveying and Mapping Error Sources Analysis

LI Tao, TANG Xinming, GAO Xiaoming, CHEN Qianfu

2017, 0(11):  37-41,50.  doi:10.13474/j.cnki.11-2246.2017.0344

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Synthetic aperture radar interferometric is one of the most efficient methods in global surveying and mapping(SAM) applications.Howerer,InSAR is easily affected by kinds of error sources in SAM applications.In this paper,We discuss the reason why domestic SAR satellites fail to provide interferograms operationally. Then we provide the error sources given the interferometric geometry. The first-level error sources of InSAR are defined as master orbital error,slant range error,baseline vector error as well as unwrapped phase error. The error sources are decomposed so that the errors of the second-lever are revealed and analyzed in the paper.

Monitoring the Surface Deformation Caused by Oil Exploration Based on InSAR

CHEN Zhimou, HU Bo, CHEN Jinzuo, LUO Chuchu, ZHANG Huapeng, YAO Junqi, CHEN Jinqing

2017, 0(11):  42-46.  doi:10.13474/j.cnki.11-2246.2017.0345

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With the development of the industrial civilization, the petroleum has become more and more important in the chemical industry. However, the negative impact of oil mining has become increasingly prominent, such as environmental pollution, resource depletion, mining safety issues, etc. The surface subsidence caused by oil exploitation is the most important problem, resulting in the decrease of the underground pressure in the oil layer, which leads to the compaction of the oil layer. When the quantity of the intensity of pressure reaches a fixed value, it will cause the surface subsidence. In the urban area, surface deformation will affect the safe usage of various production facilities. This paper takes an oilfield as the study object, using SBAS technology (small baseline subset) to monitor the surface subsidence caused by implementation of oil production activities. Eventually it provides a comprehensive analysis of the phenotypic variable rate and scope, ground deformation factors and the basis for decision-making for the production sectors and government departments.

Shoreline Surveying Method Based on the Stereo Imaging and Mapping

DANG Yamin, ZHANG Chuanyin, ZHOU Xinghua, XUE Shuqiang, XU Jun

2017, 0(11):  47-50.  doi:10.13474/j.cnki.11-2246.2017.0346

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A new method for accurately surveying and mapping the shoreline of an island is proposed where the theoretically shoreline defined by the high water (MHHW) is adopted as the shoreline indicator of the island. This method utilizes the height of the instantaneous shoreline extracted from the aerial images to obtain the height of the shoreline by combining the precise ocean tide model and the height of the instantaneous shoreline, and then the horizontal position of the shoreline can be tracked by the stereo imaging and mapping method with the obtained height of MHHW. The proposed method can keep and ensure the continuity and uniqueness of the shoreline relative to the field measurements for shoreline mapping, and this method can be widely applied to large-scale shoreline mapping of mainland and islands.Experimental test indicates that the height accuracy can reach 0.2 m and it can be applied to the island mapping of the scale 1:2000.

A CoKriging Interpolation Method Based on Principal Component Analysis

LU Yueming, WANG Liang, QIU Agen, ZHANG Yongchuan, ZHAO Yangyang

2017, 0(11):  51-57,63.  doi:10.13474/j.cnki.11-2246.2017.0347

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Aiming at the problem that the cooperative Kriging interpolation method has higher computational complexity when the auxiliary variables are numerous, and the interpolation precision is lower when the interpolation variables are less, a cooperative Kriging interpolation method based on principal components analysis is proposed (PCA-CoKriging). This method first uses the principal components analysis to reduce the dimension of the related interpolation variable, obtains several comprehensive indexes, and then uses these comprehensive indexes as the auxiliary variables to conduct cooperative Kriging interpolation. In order to verify the effectiveness of the method and the influence of the data distribution on the method, four groups of data about PM_2.5 concentration in the four seasons in Beijing in 2016 which meet different effects of normal distribution are selected, and PCA-CoKriging, ordinary Kriging interpolation method, and conventional Co-Kriging interpolation method are used to carry out interpolation experiments. The results show that the mean square error in the method of this article, ordinary Kriging interpolation method, and conventional Co-Kriging interpolation method are 4.91, 6.04 and 5.61 respectively, and the average root mean square errors are 6.65, 8.76 and 7.57 in the four groups. In comprehensive comparison, the mean absolute error and root mean square error in the proposed method have increased by 10.73% and 12.56% respectively compared with those of the conventional CoKriging interpolation, and 18.71% and 24.09% respectively compared with those of the ordinary Kriging interpolation method.

The Study of a City Smart Parking Mode Based on “Internet Plus”

ZHANG Chunju, LI Guandong, GAO Fei, SHI Chao, ZHU Shaonan

2017, 0(11):  58-63.  doi:10.13474/j.cnki.11-2246.2017.0348

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During the rapid urbanization process in China, there is an increasingly prominent contradiction between the lack of parking spaces and the increasing cars in a city. This paper made an investigation and analysis of the current situation and actual demand of the city parking. Based on mobile communication, GPS and GIS technology, and the "Internet plus" background, a smart city parking mode was designed, and a smart parking system for city cars was developed. In this system, the parking lot information from different locations was gathered together. It provided a real-time update, query, reservation and navigation services of city parking resources. This study will promote the efficient use of existing parking resources, get an optimization of the parking service, and effectively alleviate the contradiction between parking supply and demand to solve puzzle of city parking. Further, it will promote the construction of intelligent transportation and smart city.

Error Metric Model for 3D Point Cloud Reconstruction Based on Binocular Vision

BIAN Yuxia, LIU Xuejun, WANG Meizhen, ZHOU Ye, ZHEN Yan

2017, 0(11):  64-67.  doi:10.13474/j.cnki.11-2246.2017.0349

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Rapid extraction and construction of 3D model from the images play an important role in the spatial data acquisition. Considering the basic data of smart city construction, how to measure and ensure the accuracy of images-based 3D model reconstruction will become one of research questions. Firstly, the model of 3D point cloud reconstruction need to be studied, and then binocular vision 3D point cloud error metric model and quantitative expression method can be constructed, based on the matrix theory and differential covariance propagation law. This research would provide a theoretical basis for the quality control of 3D image modeling and accuracy assessment.

Application of Terrestrial 3D Laser Scanning Technology in Deformation Monitoring of Dangerous Rock Mass

ZHU Haixiong, SUI Lichun, LU Kaixiang

2017, 0(11):  68-71.  doi:10.13474/j.cnki.11-2246.2017.0350

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In this paper, a method of surface deformation monitoring of high risk rock mass based on 3D laser scanning is proposed. Firstly, the normal vector of the reference point of cloud data is calculated and the cylinder is constructed based on the normal vector of this point. And then calculating the regional center of gravity of the second-stage cloud data in the cylinder as the basis for comparing the two or more stages of the surface of the dangerous rock. We apply this method to Chongqing wulong-nanchuan district Jiguanling dangerous rock mass deformation monitoring,which gets a preliminary satisfying result.

Application of Unmanned Intelligent Technology in Topographic Surveying and Capacity Calculation of Reservoir

ZHANG Chen, MOU Naixia, ZHOU Xia, PAN Zaoxin, LI Haibin, YU Peng, YANG Ji

2017, 0(11):  72-76.  doi:10.13474/j.cnki.11-2246.2017.0351

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With the development of UAV and unmanned boat technology, its application to reservoir topography has been becoming the development trend of water conservancy project. In this paper, the unmanned aerial vehicle (UAV) and unmanned boat, as well as the calculation method of irregular triangulation are used to calculate the capacity of Meizhou reservoir. And the data acquisition method and data processing process, as well as the calculation method and principle of storage capacity are elaborated. The use of new technologies, such as unmanned aerial vehicles and unmanned boat, improves the acquisition accuracy of reservoir terrain and the calculation accuracy of storage capacity, which not only reduces the cost, improves the efficiency, but also promotes the progress of water science and technology, with practical significance.

The Land Subsidence Stratification Monitoring of Zheng-Xu High-speed Railway in Kaifeng Section

ZHANG Dan, HAO Yadong

2017, 0(11):  77-79.  doi:10.13474/j.cnki.11-2246.2017.0352

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In this paper, the factors that cause the land subsidence during the construction of high-speed railway are complicated and interactional. It is proposed that the ground water level and pore water pressure in the subsidence area are stratified observation, and the data of groundwater level change and pore water pressure change are obtained according to stratified observation. Regression analysis method to construct the correlation model of land subsidence and its influence factors in settlement area.The land subsidence monitoring of Zheng-Xu high-speed Kaifeng section is compared and analysed with the same period using second class precision level measurement points settlement. The results show that the method is effective and reliable.

A Study on the Automatic Generalization of Urban Multi-scale Electronic Map

YIN Xiangjun, WANG Furong, YIN Jie, ZHU Minqiu, WANG Shukui

2017, 0(11):  80-85,90.  doi:10.13474/j.cnki.11-2246.2017.0353

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With the openness of the government information, such as smart city, geo-information common services, and geographical conditions data, the city electronic map, which is considered to be the basis of all kinds of government affairs, can only be illustrated by shutting down and selecting elements in multi-scale display. This leads to the jumping loss and detail fragmentation phenomenon for the elements in the scaleless display. Therefore,it cannot meet the requirements of cartographic representation and satisfy the user's visual experience. This paper presents an automatic generalization method,which constructed a technology system featured unified source, consistent derivation, scaleless representations. This system realizes the linkage renewal and multi-scale display of urban multi-scale electronic map. To some extent,it will play an important role in maximizing the geographical information integration and service capabilities of surveying and mapping.

Research on Government Digital Map Compilation——Taking Beijing as an Example

WANG Xuhui, JIA Guangjun, TAO Yingchun

2017, 0(11):  86-90.  doi:10.13474/j.cnki.11-2246.2017.0354

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As a common used base map,the government digital map is a widely recognized form of using geographic information. In the paper,the methods of producing government digital map are studied. Based on the principles of using fundamental surveying data and giving priority to visualization throughout the whole process,the paper designs product forms which have two sets of coordinates and three represented forms.Also the paper proposes the whole production process,which contains confidential treatment,data processing,and special drawing,etc.Focusing on the map loading control strategy,the paper carefully analyzes the spatial scale,the performance level,the comprehensive choice and their impact on the digital map.Taking Beijing as an example,the government digital map has been produced and then widely used among the government sectors.

Research on the Technology and Method of Urban Geography Space Time Big Data Management and Application Platform

XIANG Hongmei, GUO Mingwu

2017, 0(11):  91-95.  doi:10.13474/j.cnki.11-2246.2017.0355

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According to the characteristic of spatial and temporal geographical data on urban, such as multi professional category,multi data format, data dispersion and so on, the management schemes of the grid format data, the data of the graph form, the data of the element type, the similar GIS data and the ArcGIS data of 5 kinds of geography space time data are put forward.Using map enhancement technology based on rich client, dynamic representation of temporal and spatial data based on time frame, spatial data and platform function self expanding custom technology,the overall design of the data management and application platform of the urban geography space time and space is carried out. The trinity system of resource creation and management system,information integration and sharing systems,data interactive application system is developed. The high efficiency of data management and application in urban geography time and space has been realized. The technology method proposed in this paper has been verified in the project construction of information integration management and application sharing platform for planning traffic survey in Changsha city, which provides the technical experience for the integration management and sharing application of the urban geography space time big data.

Spatial Data Parallel Partitioning Algorithm Based on MapReduce

FU Yanli, WU Yanmin, ZHANG Jinbiao, ZHENG Kun, ZHAO Changhong, ZHENG Kang, FANG Falin

2017, 0(11):  96-100.  doi:10.13474/j.cnki.11-2246.2017.0356

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Spatial data partitioning method plays an important role in spatial data distributed storage, and its key problem is how topartition spatial data to distributed storage nodes in network environment. This paper discusses massive spatial data partitioning strategies and analyses their disadvantages which these partitioning methods have not taken into account spatial object size and spatial proximity. Aiming at these questions,this paper proposes a new spatial data parallelpartitioning strategy based on MapReduce and capacity-aware method to improve load balance which could avoid unevenly distributed data storage and data skew. Experimental analysis shows that the presented spatial data parallel partitioning algorithm not only achieves better storage load balance in distributed storage system,but also keeps well spatial locality of data objects after partitioning.

Research on Wheat's Nature Water Stress Drought Evaluation Models Based on GIS

ZHU Yihan, XUE Fengchang, TANG Buxing, HUANG Minmin

2017, 0(11):  101-107,114.  doi:10.13474/j.cnki.11-2246.2017.0357

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Wheat is one of the important food crops in China.Wheat drought disasters affect food security seriously in China.Assessing wheat drought is particularly important.Nature water stress model is one of the main model of the evaluation of wheat drought conditions.This model involves lots of data types,model calculation is complicated,affecting the actual application of the model.The natural water stress model is established into GIS logical calculation model by ModelBuilder.The results showed that the natural water stress drought evaluation models based on GIS transformed complex mathematical model into simple GIS grid computing.It realized counting process automation,intergration,spatial visualization.And the model has a clear convenient for modification,maintenance of data.

Research and Implementation of the Integration of TLS Data Processing System

WANG Zhenli, WU Xiaozhang, CHEN Gang, DU Shunji

2017, 0(11):  108-114.  doi:10.13474/j.cnki.11-2246.2017.0358

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The data post-processing and software development of the terrestrial laser scanning (TLS) technology is a key factor that constrains the further development of three-dimensional laser scanning technology. In this work, combined with the Oracle storage technology, PCL algorithm and OpenGL 3D display technology, a set of the TLS data processing system with point cloud storage, processing, display and query functions was developed preliminarily. The feasibility of the TLS data processing systems developed by the proposed three technologies in this paper and the robustness of the system functions was verified via the statue point cloud data scanned by RIEGL VZ-400 scanner, which provides useful reference for further researches on the development of TLS data processing system.

Aggregation and Segmentation of Building Model Considering Property Rights

HOU Yue, LU Xiaoping, XIAO Feng, ZHANG Lichao

2017, 0(11):  115-117.  doi:10.13474/j.cnki.11-2246.2017.0359

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This article presents a method about aggregating and segmenting the building model which based on cadastral range, door model. Developing the technology which segmenting real estate model in vertical and horizontal, and aggregating real estate model based on the same property rights. Forming technology in the manufacturing process which start from collecting data, building model date and relating property rights. Using the technical of MD5 to be related the real estate model and property rights, implements the comprehensive of all kinds of 3D data visualization and dissolve analysis, which provides more intuitive decision support in 3D real estate property rights management.

Application of Voronoi Diagram in UAV Aerial Image Matching

WANG Haitao, ZHANG Dan, ZHANG Na

2017, 0(11):  118-122,127.  doi:10.13474/j.cnki.11-2246.2017.0360

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A method of generating Voronoi diagram of the spatial location of UAV aerial images is presented in this paper. This method takes the ground coverage of images into account. A matching algorithm based on local invariant features, which is transferable during the matching procedure between multi-view images, combined with Voronoi diagram of images is used to improve the matching speed and the degree of overlapping of corresponding points between multi-view images.

Remote Sensing Image Registration of Unmanned Aerial Vehicle for Marine Applications

WANG Fei, GAO Xiaowei, GAO Ning, ZHAO Jianhua, WU Hefeng, MENG Qinghui

2017, 0(11):  123-127.  doi:10.13474/j.cnki.11-2246.2017.0361

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In marine applications, large water areas lead to more difficulties compared to land on the corresponding point matching, which restricts the UAV remote sensing image registration precision and convergence speed. This paper proposes an improved algorithm for the marine UAV remote sensing applications. First, remove water using principal component analysis (PCA) and water threshold method, and obtain the block image without water. Then, feature points extraction and the corresponding points matching of these block images were performed using the affine scale invariant feature transform algorithm (Affine-Sift, ASIFT). The experiment results show that the improved algorithm can increase 30%~50% points, the accuracy increases by about 20%, and time is not increased. This method is suitable for the sequence of UAV remote sensing image registration on the marine, and it can provide effective technical support for the remote sensing monitoring of island and coastline.

Research on 3D Fine Reconstruction and Model Singling of Mountainous City Combined with Oblique Photography and Close Range Photography

LIAN Rong, DING Yi, LUO Ding, WEI Wenjie, LI Penglong, LIN Xi

2017, 0(11):  128-132.  doi:10.13474/j.cnki.11-2246.2017.0362

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The actual 3D model based on the UAV oblique photography is an effective way to perceive and express the complex mountain environment. To solve the problems in the generation of actual 3D model based on oblique photography for mountainous cities, a multi-scale image acquisition strategy suitable for mountainous region and a method of fusion modeling with close range photogrammetry is proposed in this paper. Experiments show that this method realizes the goal of precise modeling of the actual 3D model of oblique photography in mountainous cities. And then, the methods of actual 3D model's singling are introduced and compared. This paper provides some technical references for developing oblique photography in mountainous cities in the future.

Refining Model of 3D Modeling Based on Oblique Image of Unmanned Aircraft

QIU Chunxia, DONG Qiankun, LIU Ronghua, LEI Lei

2017, 0(11):  133-138,143.  doi:10.13474/j.cnki.11-2246.2017.0363

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3D modeling based on oblique image of unmanned aircraft is the first choice for 3D modeling of the city because it is fast and low cost. Multiple problems, such as data redundancy, model deformation and image deletion, often affect the modeling effect in the 3D modeling based on oblique image of unmanned aircraft. This paper puts forward a series of model refinement treatment technology for 3D modeling based on oblique image of unmanned aircraft. These techniques make the 3D model more vivid and realistic.

UAV Aerial Triangulation and Accuracy Analysis with Scarce Controls in Highway Topographic Mapping

ZHENG Liang, WANG Kansheng

2017, 0(11):  139-143.  doi:10.13474/j.cnki.11-2246.2017.0364

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Against the UAV aerial photogrammetry ground control points problem, this paper introduces a UAV aerial triangulation method. The method is based on dynamic PPP, using a single GNSS receiver to obtain coordinates of the camera site. By highway project experiments, it analyses the control point layout method and the accuracy of adjustment with scarce ground control points. The proposed method greatly reduces the effort of field work, simplifies the workflow of UAV aerial photography.

On Influence of Post-processed Difference Technique and Image Control Point Density on UAV Photogrammetry Accuracy

CHEN Pengfei, HU Haifeng, LIAN Xugang, DU Yongjun

2017, 0(11):  144-147.  doi:10.13474/j.cnki.11-2246.2017.0365

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Based on the Inpho photogrammetry software, the DOM precision and DEM precision of the UAV image data of post-processed difference and point positioning under the condition of dense image control points and sparse image control points are compared and analyzed. In the test area of 1 km², 68 image control points and check points are laid. By adjusting the number and layout position of image control points of the involved calculation, the inspection points are used to verify accuracy of the generated DOM and DEM. Through the experiment, it is found that the accuracy of UAV photogrammetry results is improved remarkably based on the post-processed difference technique and the reasonable layout of the control points. In this experiment, the highest precision reaches the plane ±4 cm and the elevation is ±9 cm. Therefore, post-processed differencing technique and reasonable image control point layout are of great significance for large scale UAV digital mapping.

Exploration on Talent Training Mode of GIS Cloud Computing

ZHENG Kun, LIU Hongyu, LI Qi, GONG Junfang

2017, 0(11):  148-150,154.  doi:10.13474/j.cnki.11-2246.2017.0366

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The emergence of cloud computing technology has great impact on the traditional GIS industry and good prospects for development, combined with the cloud computing technology to develop GIS system and services has become the development trend of GIS industry. Therefore, the cloud computing technology is very important in the cultivation of GIS personnel training. However, the current GIS courses are not involved in cloud computing technology, students can not master the knowledge and skills related to cloud computing. In order to solve this problem, according to the knowledge module of cloud computing technology in GIS, this paper analyzes how to improve students'ability of cloud computing through competition, and explores the training mode of "promoting learning by competition". This paper provides a new method for training professional GIS cloud computing talents.

Development of the Major Teaching Resource Library of Surveying and Mapping Geographic Information from the Perspective of Learning Analysis

HUANG Rui, ZENG Chenxi, LI Changqing

2017, 0(11):  151-154.  doi:10.13474/j.cnki.11-2246.2017.0367

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According to the present situation of the construction and application of the major teaching resources library, this paper analyzes the problems existing in the construction, including the user service, the organization of information resources and the guidance of the learning process. This paper tries to develop a learning platform based on the data acquisition, model analysis and visual feedback. Besides, it tries to achieve the personalized teaching function and solve the problems such as self discrepancy analysis, self assessment and orientation analysis, self analysis and monitoring analysis. Therefore, a case study of the curriculum resources development on geographic information system in the major of surveying and mapping geographic information is introduced. This paper makes an empirical analysis on the application of learning analysis in the design of the platform framework and the design of the platform operation flow.