Table of Content

25 July 2021, Volume 0 Issue 7

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LiDAR point cloud ground filtering algorithm in dense and low vegetation area

YAN Yueguan, CHEN Zhongzhang, SUN Yang, LI Zezheng, YAO Chengzhi

2021, 0(7):  1-5.  doi:10.13474/j.cnki.11-2246.2021.0199

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Aiming at the characteristics of LiDAR point cloud in mining areas with complex terrain and dense low vegetation, this paper proposes a ground filtering algorithm based on slope information combined with plane fitting. This method uses the second-level grid method to select ground seed points by hierarchical extraction, and uses the ground seed points in each first-level grid to construct a ground model by plane fitting through the least squares fitting method. Finally, ground point and non-ground point can be distinguished. Through comparative experiments with the traditional slope filter and cloth simulation filter, it is concluded that this method can effectively filter out dense and low shrubs and can better retain the larger slope terrain.

An easily FLAC3D modeling method based on geological information interpolation

LI Peixian, CAO Yuxi, YANG Zhonghui, HAO Dengcheng

2021, 0(7):  6-11.  doi:10.13474/j.cnki.11-2246.2021.0200

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To obtain an easily method of FLAC3D modelling and reduce the difficult of using of FLAC3D, a program is developed using python. This program using the stratigraphic information to generate the discrete grid points based on Kriging interpolation first. And then the program can generate the FLAC3D grid format file automatically. The generated file can be imported into the FLAC3D software and a 3D model can be obtained directly and easily. It is faster and easier than using the inner modeling script. The program provides three basic elements model of the FLAC3D. The method can generate accurate 3D model using the Kriging interpolation. Three applications and some results of coal mines are given in the paper. Those applications show that it can generate accurate 3D model for complex topography. The research results provide a tool for building 3D models in complex geo-conditions simulation.

Mining vehicles loading estimation by single-pulse laser scanning

LU Xingzheng, XU Zhihua, XU Ershuai, MAO Yachun

2021, 0(7):  12-16.  doi:10.13474/j.cnki.11-2246.2021.0201

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Facing the demand of loading volume estimation for vehicles in open pit mines, this paper proposes an automatic measuring method using single-pulse laser scanning. First, we use a fixed single pulse laser to scan the target vehicle in a bird view, and then segment the point cloud of the load surface using the vehicle morphological features. Following that, we reconstruct the load surface model by temporal correction and matching the pre-constructed vehicle database, and finally estimate the loading volume by slicing and integrating the surface model. We apply the proposed method to Qidashan iron ore open pit mine for load volume estimation. Experimental results show that the proposed method enables to obtain the surface 3D point cloud of the load in real time under the moving conditions of vehicles. Besides, the average error of 3D modeling is 2.54 cm, whereas the error of load volume estimation is 1.17%.

Analysis of soil moisture content changes in resource-based cities over a long time series: a case study of Xilinhot city

LI Jun, SANG Xiao, ZHANG Chengye, ZHAO Wei, LIU Xinhua, WANG Hongpeng, WANG Jinyang, LI Jiayao, YANG Ying

2021, 0(7):  17-22,38.  doi:10.13474/j.cnki.11-2246.2021.0202

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Large-scale coal mining activities have disturbed the ecological environment. Soil moisture content is important as one of the disturbed ecological parameters. Currently, existing soil moisture content products have coarse resolution and are not suitable for regional scale studies, while microwave inversion of soil moisture content with fine resolution are limited by the data so that can not be used for long time series studies. This paper takes Xilinhot, an important coal production base in China, as the study area, and uses AMSR-E, AMSR-2 soil moisture content products from 2004 to 2020 and Landsat remote sensing images for the same period as the main data sources. The random forest method is used to downscale the AMSR-E/2 soil moisture content products. The variation characteristics of soil moisture content in the study area are analyzed by standard deviation ellipse. And the results show that:① Passive microwave soil water moisture downscaling method enables long time series and high spatial resolution monitoring of soil moisture content in resource-based cities. ② Precipitation is the dominant factor affecting soil moisture content changes in both mining and non-mining areas. ③ The overall distribution of soil moisture content in the study area shows a gradual increase in spatial characteristics from northwest to southeast, and this distribution pattern remained stable over long time scales. ④ Coal mining activities disturb soil moisture content, and the impact of different mining stages has different characteristics. The results of the study provide a scientific basis for the evaluation and protection of the ecological environment of coal cities.

Evaluating ecological environment based on remote sensing ecological index in Shenfu mining area

FAN Deqin, QIU Yue, SUN Wenbin, ZHAO Xuesheng, MAI Xiamei, HU Yingwen

2021, 0(7):  23-28.  doi:10.13474/j.cnki.11-2246.2021.0203

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Monitoring and evaluating the ecological environment with the help of remote sensing technology is of great significance for the sustainable development of mining area. In this paper, an improved scheme of remote sensing ecological index (RSEI) is proposed. Based on the original model which contains four ecological indexes (NDVI, WET, LST, NDSI), the net primary productivity (NPP) of vegetation is introduced to characterize the ecosystem function of mining area. The ecological environment of the mining area is evaluated and analyzed by every single ecological index using the five ecological indexes. Using the improved remote sensing ecological index, the ecological environment changes of Shenfu mining area from 2000 to 2016 are evaluated. The evaluation results show that the remote sensing ecological index of Shenfu mining area shows an overall upward trend from 2000 to 2016 (0.1/10 a), and the vegetation productivity in most areas increases gradually, which means that the ecosystem function recovers gradually, and the ecological environment quality improves gradually.

Forest density mapping based on UAV high-resolution image

GUO Wei, YANG Chunyu, WU Ziruo, JI Xianglin, YANG Chunjie, ZHAO Chuanwu, ZHANG Yuhuan

2021, 0(7):  29-33.  doi:10.13474/j.cnki.11-2246.2021.0204

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Based on the UAV remote sensing data of Daxing'anling Mountains, this paper proposes a local threshold algorithm for forest density mapping. Compared with the traditional Otsu method to remove the background noise, it is concluded that this method can remove the noise background well in the areas with medium or low forest density. Combined with the local maximum method, it has good single tree extraction accuracy, and its recall rate reaches 100%. The traditional Otsu background removal method has a good recognition effect in high forest density area, but its disadvantage is the wrong information extraction of non-forest open space. Through the comparative study of the above two methods, the mapping results of forest plant density in Daxing'an Mountains are obtained, which can provide a reference for the mapping of forest plant density in sparse forest areas.

Step-by-step identification method of crop leaf diseases based on transfer learning

ZHAO Hengqian, YANG Yifeng, LIU Zelong, SONG Rui

2021, 0(7):  34-38.  doi:10.13474/j.cnki.11-2246.2021.0205

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Accurate identification of crop diseases can help improve the yield and quality of crops. As image training sample data of crop disease is limited, this paper adopts the transfer learning method combine with the step-by-step identification model to identify a host of crop disease types. Taking PlantVillage public data set of ten types of crop leaf images of three crops as training samples, the paper uses the direct recognition method to train the original model of VGG16 and ResNet and the model of transfer learning respectively, and obtain the classification results of the model. This paper proposes a step-by-step identification method, the training samples are classified according to the types of crops and disease types, the models are trained separately, and a step-by-step identification model is constructed. The experimental results show that the transfer learning method can increase the recognition accuracy by more than 20% on the basis of the original model. On the basis of this, the step-by-step identification method is introduced and compared with the direct recognition method, the accuracy of the VGG16 and ResNet models is increased by 14% and 8%, respectively. The transfer learning step-by-step identification method proposed in this research can realize the accurate identification of crop diseases in the case of small samples of training data, and can provide effective technical support for crop disease prevention and control.

Crop planting structure identification based on Sentinel-2A data in hilly region of middle and lower reaches of Yangtze River

TAO Li, HU Zhaoling

2021, 0(7):  39-43.  doi:10.13474/j.cnki.11-2246.2021.0206

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In order to solve the problems of small and broken parcels, complex planting structure, entanglement of crop remote sensing spectral features and difficulty in accurate information extraction in the hilly area of the middle and lower reaches of the Yangtze River, a more precise identification method of crop planting structure based on Sentinel-2A data is proposed in this paper. Firstly, the key phenological features of the main crops in the study area are obtained. Secondly, the spectral features, texture features and terrain features are calculated to construct the original feature sets. Finally, the importance of the features is sorted by using the random forest method, the feature variables of the original feature set are optimized, and the optimized combination features are selected for supervised classification to extract the crop information in the study area. The results show that:compared with the univariate feature, the overall classification accuracy and kappa coefficient are improved from 80.4% and 0.748 to 96.3% and 0.954 respectively which effectively improves the accuracy of crop classification in southern hilly area, and the algorithm robust is more stable.

Remote sensing image change detection based on improved interval type-2 fuzzy clustering

SU Yifan, DANG Jianwu, WANG Yangping, YANG Jingyu

2021, 0(7):  44-51,58.  doi:10.13474/j.cnki.11-2246.2021.0207

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The complex fuzziness of remote sensing image can interfere with the result of image change detection so that the interval binary fuzzy C-means clustering algorithm is introduced to solve the problem. But the randomness of algorithm parameters will affect the accuracy of change detection. In this paper, the candidate solution of firefly algorithm is optimized by using local optimal solution, and the variable step size factor is introduced, so as to find the fuzzy factors of interval type-2 fuzzy C-means clustering algorithm adaptively. The interval type-2 fuzzy C-means clustering is carried out combining with the fuzzy factors obtained by optimization and the image change information is extracted by iteratively updating the membership degree. Finally, the weighted Karnik-mendel algorithm based on compound trapezoid rule is used to reduce type and resolve fuzzy to optimize clustering centre. And the change types are determined according to the principle of maximum membership. Through experimental verification, the method in this paper obtains the better fuzzy factors and more accurate clustering centers, has better robustness, and improves the change detection accuracy, and the detected change area is more elaborate.

Assessment of disaster-prone areas considering the influence of terrain and neighborhood

XU Gang, HU Kunlin, WEN Jianfeng, XU Dengcai, DAI Xinyi, CHEN Jie, ZHU Anfeng, ZHANG Hao, SU Zongkui

2021, 0(7):  59-64.  doi:10.13474/j.cnki.11-2246.2021.0209

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Geological disasters usually cause huge human and material damages. Evaluation of disaster-prone areas is an important means of disaster prevention and mitigation. In order to minimize the economic losses and casualties caused by disasters, this paper carries out geological disaster risk assessment research with the support of GIS. Based on the physical geography of Wenzhou city and historical data of related disasters, we analyze the influence factors of geological disasters such as elevation factors, slope factors, and aspect factors. Furthermore, we propose a comprehensive analysis method of geological disasters in the adjacent environment, and use the analytic hierarchy method to calculate the weight of each factor. We also construct the evaluation index system of Wenzhou landslide hazard susceptibility to determine Wenzhou's geological hazard prone areas. At the same time, the law of geological disaster risk under different terrain conditions in mountainous and plains is also studied. The results show that the high-risk areas in Wenzhou are mainly located in the middle and high mountains in the west, and the low-risk areas are mainly located in the eastern plains. This result can serve the disaster prevention and control work in Wenzhou.

Application of airborne LiDAR and UAV image fusion for complicated terrain

GAO Sha, YUAN Xiping, GAN Shu, YANG Yafu, LI Xia

2021, 0(7):  65-69.  doi:10.13474/j.cnki.11-2246.2021.0210

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Aiming at the advantages and disadvantages of LiDAR point cloud and UAV image data, the LiDAR point cloud and DOM image of UAV are combined to transfer the spectral information of image data to LiDAR point cloud data, so that it not only has accurate spatial structure information, but also can obtain clear texture information. In order to verify the feasibility of fusion data application and the accuracy of data extraction, ground point extraction and DEM construction are carried out on point cloud data before and after fusion. The experiment shows that the LiDAR point cloud data can be extended from four dimensions to seven dimensions by transferring the spectral information of UAV image to the LiDAR point cloud data. After the fusion, the point cloud data has clear texture information, the ground object type is easier to interpret, and the ground points are separated completely. Through the comparative analysis of DEM model, the expression of DEM model constructed by integrating point cloud data is closer to the real surface. The research results provide some technical support for the further application of multi-source point cloud data.

Three-dimensional automated road modeling method for high-precision vector data

LI Xiaoli, LIU Rufei, TANG Yubing, REN Hongwei, CHAI Yongning

2021, 0(7):  70-73.  doi:10.13474/j.cnki.11-2246.2021.0211

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In order to solve the problems of slow road manual 3D modeling and heavy workload, this paper focuses on standardized processing of high-precision vector data, carries out refined design for different intersections, and automatically generates road 3D models. First, this paper uses road high-precision three-dimensional information acquisition software to semi-automatically extract accurate road edges, road markings and other vector information from the acquired point cloud data. Then, it carries out refined linear design for different intersections, and proposes continuous quadrilateral reconstruction methods and curves smoothing processing method, intersection reconstruction method and road marking reconstruction method. Finally, the extracted high-precision vector data is standardized. After meeting the road alignment design requirements, MAXScript is used to realize the road 3D automatic modeling. Taking the point cloud data of a certain section of the road obtained by the vehicle-mounted mobile measurement system as an example, the experiment verifies the feasibility and effectiveness of the method.

Registration of fisheyes panoramic image and terrestrial LiDAR date based on line feature

XIONG Youyi, QIAO Jigang, ZHANG Wenjin

2021, 0(7):  74-80.  doi:10.13474/j.cnki.11-2246.2021.0212

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Combining terrestrial laser point cloud and fisheye image are high efficiency on panoramic information analysis. Registration of fisheyes panoramic image and terrestrial LiDAR data is a prerequistite for its information complement each other. But it is necessary to overcome the difficulties of data dimensional difference transformation and feature matching. In this paper, a new semi-automatic method is brought up to registered these two data based on Hough algorithm, both fisheyes image and LiDAR points are reprojected to a same cylindrical surface. Line features are extracted from these two images based on Hough algorithm. And then, the modified Iterated Hough transform is employed to registered LiDAR range image and fisheye cylindrical surface image. Experimentation shows that the model has capability to register these two data in 3D screen with less manual intervention, and obtain high register precision within the area near fisheyes image viewing point.

Analysis of surface time series deformation in Lincang city based on SBAS technology

WENG Changkai, XIAO Tian

2021, 0(7):  81-85.  doi:10.13474/j.cnki.11-2246.2021.0213

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As a microwave remote sensing technology, SBAS monitoring technology uses least squares or singular value decomposition methods to interfere with multiple interfering pairs forming a triangulation network to obtain the time series deformation law of a certain area. This paper uses SBAS technology to process the 30 Sentinel-1A radar data covering Lincang city from February 2019 to July 2020. This area is analyzed by means of profile and time series analysis to study the causes and laws of its surface subsidence, so as to judge whether there are hidden danger areas of geological disasters in this area, and provide reference opinions for the future disaster prevention and mitigation work of Lincang city.

Deformation monitoring along Fuzhou metro line based on radar technology

CHEN Anping, TAN Yuanmo, YANG Cheng, QIN Yongji

2021, 0(7):  86-91,97.  doi:10.13474/j.cnki.11-2246.2021.0214

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In recent years, the massive construction of underground projects such as subways in China has produced serious surface subsidence, which leads to many geological hazards in cities and hinders the development of urbanization in China.Therefore, the use of high spatial resolution and high temporal resolution monitoring technology for urban geological hazards monitoring as well as risk assessment is of great importance for the healthy development of cities. In this study, we apply the SBAS-InSAR technique to monitor the land subsidence in Fuzhou downtown after the program of metro construction. 24 scenes of X-band TerraSAR data from July 2013 to August 2015 and 32 scenes of C-band Sentinel-1 data from July 2015 to February 2018 are used in this experiment. Our results show a maximum subsidence rate of -12 mm/a, and eight subsidence funnels have been found during the observed period. After analyzing the subsidence of these regions in a long time span, it can be concluded that three areas show the characteristics of the initial stage of geological disaster, and there is a possibility of further intensification of surface subsidence.

Application of time series InSAR technology in prevention and control of surface deformation disaster of high-voltage transmission line

ZHU Xingang, MING Sheng

2021, 0(7):  92-97.  doi:10.13474/j.cnki.11-2246.2021.0215

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On June 12, 2020, a rainstorm and waterlogging accident occurred on the high-voltage transmission line of Sencong line in Conghua district, Guangzhou city, resulting in collapse and waterlogging accidents in many tower areas. The study should use SBAS technology and based on the Sentine-1A data to obtain the regional surface shape variables from January to June in 2020 in the north of the chemical industry. The influence of heavy rainfall on the surface deformation of mountain body is studied. The comprehensive analysis and monitoring results show that most of the areas tend to be stable in the meantime, and some hilly areas are affected by external conditions and under the influence of high soil water content, it presents an unstable and continuous settlement trend. In the season with the heavy rain, the surface settlement rate will increase significantly, and the maximum settlement is more than -55.3 mm in the meantime. The seasonal heavy rainfall and human frequent construction activities brought by subtropical monsoon climate make landslides, waterlogging and other natural disasters prone to occur, which have a negative impact on regional environmental stability and security, regional development as well as the economic growth.

Early identifying and monitoring landslides in Guizhou province with InSAR and optical remote sensing

WU Lüchuan, WANG Jianhui, FU Yan

2021, 0(7):  98-102.  doi:10.13474/j.cnki.11-2246.2021.0216

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The topography and landforms of Guizhou province in China are complicated, and the climatic conditions of heavy precipitation make landslide disasters in Guizhou province occur frequently. To avoid damage bringing to people's lives and economic property caused by disasters, a reliable early landslide identification method and landslide monitoring method are urgently needed. Traditional landslide identification and monitoring methods have limitations. InSAR technology has unique advantages in large-scale landslide identification and monitoring, but landslide identification results based on a single deformation value are one-sided. Therefore, this paper uses Sentinel-1A Radar satellite image data and uses InSAR technology and optical remote sensing technology togather to carry out large-scale surface deformation monitoring and identification of dangerous deformation areas in Liupanshui city, Tongren city, Guiyang city and other regions in Guizhou province. The potential landslide identification methods based on the time series normalized difference vegetation index and landslide development environment elements are combined to investigate hidden landslide hazards in the study area. In this paper, time series InSAR technology is used to monitor key landslides in Yujiaying, to grasp the movement status of the landslide in time. The method of landslide identification and monitoring in this paper is of great significance for disaster prevention and management in Guizhou province.

Monitoring surface deformation in Songming county using time series InSAR technology

HUANG Junsong, ZHANG Chunyou, WANG Jianhui

2021, 0(7):  103-106,116.  doi:10.13474/j.cnki.11-2246.2021.0217

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Urbanization is the general trend of modern human environment and the embodiment of each country's modernization degree. China has issued many policies for rural urbanization. Songming county, Yunnan province, is established as a county-level Songming city in 2018. It can be seen that Songming county develops rapidly compared with other counties. However, the rapid development of cities will also cause many problems, among which the more serious is the surface deformation, which is easy to evolve into geological disasters. Based on the current situation of Songming county, 44 sentinel-1 satellite images are used to monitor the surface deformation of Songming county through the severe weather such as cloud, rain and fog by SBAS-InSAR technology. The deformation monitoring results of the region from January 2019 to August 2020 are obtained. The causes and laws of the deformation are analyzed by point line surface analysis method, to provide reference for the urbanization process of Songming county.

Application of high precision real scene 3D model and water quality inversion in investigation of sewage discharge outlets

MA Li

2021, 0(7):  107-110.  doi:10.13474/j.cnki.11-2246.2021.0218

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In the process of sewage outlets investigation, it is often impossible to find hidden sewage outlets under trees and bridges by using orthophoto alone. In order to solve this problem, this paper selects the main stream area of Songhua River, and proposes a hybrid interpretation method using UAV orthophoto, 3D model and water quality inversion parameters. Firstly, the key investigation area is determined by the abnormal information of water quality parameters, and then the large-scale investigation is carried out by orthophoto to mark the suspected sewage outlets. At the same time, the real 3D model constructed by oblique photography is used to interpret the key areas and suspected sewage outlets. This method is conducive to the rapid and efficient search for hidden sewage outlets, and has great significance for tracing the source of river and marine water pollution.

3D modeling of abrupt large elevation difference field based on consumer UAV

SUN Baoyan, WEI Longhua, ZHOU Xin, QIN Yucheng, ZHANG Xiaoke

2021, 0(7):  111-116.  doi:10.13474/j.cnki.11-2246.2021.0219

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Smart cities are developing rapidly, and the pace of city information modeling (CIM) basic platform construction in various places is accelerating. Therefore, it is necessary to construct high-efficiency and high-quality three-dimensional city models of different types of sites. In view of the shortcomings of the traditional aerial photography modeling method in 3D model reconstruction of the abrupt large elevation difference site, this paper puts forward a method that uses consumer UAV to take aerial photos of the abrupt large elevation difference site in a ladder way, and uses the tilt photography technology to build the 3D model. At the same time, the comparative study of Guilin Nanzhou bridge is carried out by using this method and the traditional five shot aerial photography modeling method. The model reconstructed by this method has higher accuracy, improved efficiency, and better model details. This method is capable of high-quality and efficient three-dimensional reconstruction of the abrupt and large height difference site, which provides a better choice for the creation of CIM and promotes the development of smart cities.

Research on classification of fine catchment in large-scale plain cities

WANG Yan, FAN Zixian, LI Chengming, DAI Zhaoxin, WU Zheng

2021, 0(7):  117-120,125.  doi:10.13474/j.cnki.11-2246.2021.0220

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In the study of urban waterlogging simulation, the division of catchment areas is a very important link. At the same time, the fine division of catchment areas of large-scale plain cities is also a technical difficulty that researchers jointly study. Aiming at the problems of the existing classification methods based on DEM flow analysis that cannot correctly reflect the complex terrain and flow directions of actual cities, this paper proposes a fine watershed classification method that takes into account land types and flow directions and is suitable for large-scale plain cities. First, starting from the city's natural topography and main rivers, the first-level macro-scale division is carried out. and then the second-level meso-scale division is realized based on the city's main and secondary arterial roads, main canals and pipe networks. Finally, on the basis of the second division, the flow direction the land type is divided into a fine three-level subcatchment micro-scale. This paper selects the 30 km² core main urban area of Dongying City for verification and analysis. The research results show that the classification results are consistent with the actual feature types and real flow directions. This method has good applicability to large-scale plain cities.

IMU calibration using Vicon system

WANG Zhigang, GUO Hang, AO Longhui

2021, 0(7):  121-125.  doi:10.13474/j.cnki.11-2246.2021.0221

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Aiming at the problem that the traditional IMU calibration method is complicated to operate and relies too much on the turntable, an IMU calibration method for Vicon system is proposed. Firstly, the pre-integration technique is used to fuse the IMU data with the Vicon data to obtain the IMU residual. Then, the state quantity between the adjacent frames of Vicon is subtracted to obtain the Vicon residual. Finally, the IMU residual and the Vicon residual are put into the same state vector, and the marginal prior information is introduced to establish a nonlinear optimization function, and the zero offset estimation parameters of the gyroscope and accelerometer are obtained by solving.In the meantime, the EuRoc data set test experiment and indoor positioning comparison experiment are designed. The experimental results show that the calibration result of this method for IMU has higher accuracy whichis much better than that of the traditional method.

Application of geographical information intelligent monitoring for forest fire prevention and extinguishment

ZHAO Yunhua, QIAO Xin, ZHU Fengjie

2021, 0(7):  126-130.  doi:10.13474/j.cnki.11-2246.2021.0222

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In order to meet the monitoring demands of forest fire before, during and after the event, this paper uses the surveying and geographic information technology to construct a comprehensive intelligent monitoring technical system for forest fire prevention and extinguishment. This research obtained multi-source geograhpic information data to build a forest fire prevention and extinguishment database. Based on this database, it could supply a series of intelligent monitoring service for fire prevention and extinguishing capacity assessment, normalized monitoring before fire, dynamic monitoring during fire, post-fire assessment and long-term post-fire vegetation recovery. The practicability of the technical system is tested during the forest fire event in Xiaozhushan hill. The results prove that it is a reliable and accurate intelligent geographical information solution for forest fire prevention and extinguishment.

New surveying and mapping for the urban digital transformation of Shanghai

GU Jianxiang, DONG Zhen, GUO Wang

2021, 0(7):  131-134,139.  doi:10.13474/j.cnki.11-2246.2021.0223

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Urban digital transformation, "scientific, refined, and intelligent" urban governance, the implementation of "new infrastructure" and the development of digital economy all urgently need spatial geographic data to advance to "full domain, holographic, full space, multidimensional, and high-frequency" and realize the digital twin of physical space. This article combines the new needs of geographic information in the urban digital transformation of Shanghai, proposes a new surveying and mapping system with intelligent pan-info surveying and mapping which based on geographical entities as the core from the aspects of multiplatform collection technology, holographic data content, 2D and 3D integrated form of results, update method and on-demand assembly of services, and forms a solution to new geographic information services for urban digital transformation.

Reconstruct the position and orientation of the complementary image by basic matrix

ZHANG Qingbin, ZHAO Zhixing, LU Xiaohong, XUE Yongan

2021, 0(7):  135-139.  doi:10.13474/j.cnki.11-2246.2021.0224

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The blind spot images collected on the ground often lack pose information, which will cause stratification when combined with aerial image processing. Therefore, to improve the precision of the tilt model a new method is proposed to reconstruct the position and attitude of the complementary image by constraining the pair extreme singular matrix. Firstly, feature matching is carried out to obtain the pair singular matrix, namely the fundamental matrix. The projection matrix of aerial image is assumed to be normalized, and the projection matrix of ground image is composed of anti-symmetric matrix and non-singular matrix decomposed from the basic matrix. Then, the POS information of aerial image is used to eliminate the ambiguity of the projection matrix pair, so as to obtain the accurate position and posture value of the ground image. The test results show that this method can automatically calculate the position and pose information of the ground blind area retaking image without image control, and it is well matched with the aerial image, which improves the operation efficiency under the premise of ensuring the precision of the model.

Research on the digital protection of Dongguan historical buildings

GAO Yizhong, CHEN Minghui, HUANG Yan

2021, 0(7):  140-143,149.  doi:10.13474/j.cnki.11-2246.2021.0225

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Based on the site investigation of 278 approved historic buildings in Dongguan city, this paper realizes information collection and digital database construction using UAV, 3D laser scanning and other spatial information technologies. It Combines digital management platform and public service system which comprehensively displays and disseminates the cultural value of Dongguan historical buildings. The purpose is to explore a new mode of combining digital technology and historical building protection, to provide new ideas for the preservation, protection, activation, utilization and dissemination of traditional cultural resources, and promotes the protection and management of historical buildings to be scientific, complete, systematic and shared development.

Road surface model acquisition under synergy of drainage pipeline point and road curvature

MAO Taomin, FAN Yewen, ZHI Shuang, ZHANG Yuhui

2021, 0(7):  144-149.  doi:10.13474/j.cnki.11-2246.2021.0226

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The lack of data confidentiality and sharing mechanism leads to the low accuracy of road terrain data used by urban water utilities for rainfall-runoff simulation, which reduces the prediction and defense of accuracy of urban waterlogging spatial distribution. However, the elevation information of the drainage line point data owned by the city water department can reflect the road fluctuation. In this paper, firstly, a high precision road surface model is obtained based on the data of drainage pipeline points and road design curvature data. In this way, road surface feature points are obtained by interpolation, and then road surface model is obtained by pipeline points and road surface feature points. Finally, The feasibility of the method is verified by the data of drainage pipeline points and road sideline in Wuhan.

Analysis of natural resources ecological spatial characteristics and suitability evaluation: taking Jinshan district in Shanghai as an example

XIN Jing, ZHANG Wen, LI Shuyao

2021, 0(7):  150-155.  doi:10.13474/j.cnki.11-2246.2021.0227

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This paper takes Jinshan district in Shanghai as an example. According to the data of geographical conditions, from the perspectives of comprehensive evaluation model of basic evaluation index, biological richness index and ecological landscape spatial pattern index, in addition to the conventional basic evaluation indicators, combined with the index of ecological space landscape pattern and the index of biological richness evaluates the ecological space suitability of the streets and towns in Jinshan district. The technical methods and routes in this article can provide certain technical support for relevant departments to carry out ecological environmental assessment, to coordinate the spatial requirements of various plans, and to strengthen land use control.

The exploration and practice of geographic information science specialty construction in Central South University

DENG Min, CHEN Jie, LIU Huimin

2021, 0(7):  156-159.  doi:10.13474/j.cnki.11-2246.2021.0228

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The "Double Ten Thousand Plan" of the Ministry of Education emphasizes the construction of a first-class profession that faces the future, adapts to needs, leads development, is advanced in concept, and has strong guarantees. This article explains how the geographic information science major of Central South University combines school positioning and professional characteristics, and teaches students in accordance with their aptitude, and has a unique professional construction road. It explores and implements a series of measures for the geographic information science major of Central South University. The professional development has made great progress.

Analysis of deformation characteristics of landslide disaster based on spaceborne SAR

SHI Dejie, JIANG Jinxiong, DU Sunwen, ZHANG Qimin

2021, 0(7):  160-162,166.  doi:10.13474/j.cnki.11-2246.2021.0229

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In order to accurately monitor the activity status of key landslides and prevent potential geological disasters, the article uses the pixel-tracking technology to obtain the movement distribution of the Jinsha River Baige landslide in three consecutive time periods from 2017 to 2018 based on 4 scenes of ALOS-2 data. The results show that there are significant temporal and spatial differences in the movement of the landslide body. The comparison of speeds in different periods shows that the sliding displacement of the landslide has a clear acceleration trend in the early stage of the disaster.

Construction of informatization management platform for large-scale urban terrain dynamic patch surveying

NI Xiaodong, ZHOU Wanying, WU Tangxia, LIU Muyang

2021, 0(7):  163-166.  doi:10.13474/j.cnki.11-2246.2021.0230

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The large-scale terrain dynamic patch surveying is an effective way to obtain the latest geographic information. It is an important work to ensure the current situation of the topographic map and the service capability of the geospatial framework.This paper analyzes the management process of dynamic patch surveying of topographic maps in urban areas, points out the problems of traditional management method. And proposes multi-channel change discovery and timely releases, online task transfer and supervision management, element-based data storage and increment update and other informatization construction methods. Based on this, an informatization management platform for dynamic patch surveying of large-scale topographic maps is built. The construction results of this paper have been applied to the Shenzhen 1:1000 topographic map object-oriented dynamic patch surveying work, which has fully verified its effectiveness.