Table of Content

25 June 2022, Volume 0 Issue 6

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Lane-level high-precision positioning algorithm based on integrated spatio-temporal proximity and CNN

TENG Wenxin, ZHANG Jianchen, SHAO Jie

2022, 0(6):  1-5,61.  doi:10.13474/j.cnki.11-2246.2022.0162.

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Improving the accuracy of lane-level positioning is one of the most important technologies for the development of intelligent transportation system(ITS). We propose a new lane-level positioning method called spatio-temporal proximity and convolution neural network(STP-CNN), in which STP is designed to dynamically refine candidate matching roads, and personalize CNN is further adopted to adaptively identify the optimal matching lane. By optimally integrating parameters such as GPS receiver, driving speed and inertial measurement unit for the new method, centimeter-level and lane-level vehicle position is estimated smoothly. The test results justify the feasibility and efficiency of the proposed method.

An indoor parking lot vehicle positioning method assisted by environmental semantic information

ZHOU Baoding, YANG Chengjing, GU Zhining, LIU Xu

2022, 0(6):  6-11,75.  doi:10.13474/j.cnki.11-2246.2022.0163.

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Aiming at the problem that the GNSS signal is limited in the indoor parking lot environment and cannot be used for vehicle positioning, this paper proposes an indoor parking lot positioning method based on environmental semantic information. This method uses smartphone to identify the semantic information(bumps and turns) in the indoor parking lot by machine learing, establishes the topological structure of the indoor parking lot road network. Then, particle filter algorithm is used to fuse the traditional vehicle dead reckoning data. Finally, experimental results show that this method effectively eliminates the cumulative error of vehicle dead reckoning, with an average positioning accuracy of less than 3 m, and reduces the computational time of traditional particle filtering methods through semantic information matching.

BDS-3+GPS precise point positioning modeling and performance analysis

CHEN Yibiao, BEI Jinzhong, GU Shouzhou, YANG Lijun, WANG Hongbin, CHU Bin

2022, 0(6):  12-17,39.  doi:10.13474/j.cnki.11-2246.2022.0164.

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The BeiDou navigation satellite system is officially completed and put into operation in July 2020. Based on B1I and B3I, the BDS-3 satellite adds B1C and B2a civil frequencies. In order to verify the positioning performance of BDS-3 with different frequencies combined with GPS, the PPP positioning performance of BDS-3(B1I+B3I)+GPS and BDS-3(B1C+B2a)+GPS is analyzed, and compared with that of BDS-3. The results show that in static positioning, the elevation direction accuracy of BDS-3(B1C+B2a)+GPS is lower than that of BDS-3(B1I+B3I)+GPS, the horizontal accuracy is similar, and the convergence time is reduced by 9%; The horizontal accuracy of BDS-3(B1C+B2a)+GPS is better than 1 cm, and the elevation accuracy is better than 2 cm. Compared with BDS-3, the positioning accuracy is improved by about 10%~25%, and the convergence time is reduced by 17%~24%. In kinematic positioning, the positioning accuracy of BDS-3(B1C+B2a)+GPS is equivalent to that of BDS-3(B1I+B3I)+GPS, and the convergence time is reduced by 14%; The horizontal accuracy of BDS-3(B1C+B2a)+GPS is better than 3 cm, and the elevation accuracy is better than 4 cm. Compared with BDS-3, the positioning accuracy is improved by about 31%~38%, and the convergence time is reduced by about 52%~58%.

Review of coastal ecological environment monitoring based on unmanned aerial vehicle remote sensing

HU Yiqiang, YANG Ji, JING Wenlong, YANG Chuanxun, SHU Sijing, LI Yong

2022, 0(6):  18-24.  doi:10.13474/j.cnki.11-2246.2022.0165.

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In this study, we introduce the history and current situation of development of UAV remote sensing systems by introducing the application status of UAV platform and UAV remote sensors from the perspective of coastal ecological environment monitoring. Then we review UAVRS applications in eight different areas of the coastal ecological environment monitoring, which provides evidence of the potentials and effectiveness of UAVRS for coastal zone management. This study points out that in order to further improve the application effect of UAVRS in coastal ecological environment monitoring, it is necessary to conduct further research and improvement in UAV remote sensors, setting out ground control points (GCPs), spectral data processing and other related technologies. In the future, with the improvement of UAV data transmission speed and the development of UAV AD hoc network technology, it is expected to achieve efficient and intelligent monitoring of coastal ecological environment.

A review of urban ecosystem security assessment and future directions

SU Xiaoxia, LI Renjie, WU Jing, CHENG Penggen, WANG Baoguo

2022, 0(6):  25-31.  doi:10.13474/j.cnki.11-2246.2022.0166.

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The resource pressure brought by rapid urbanization challenges the urban ecosystems, and maintaining urban ecosystem security is very important for both urban eco-environmental health and urban high-quality sustainable development. This study reviews the progress in the ecosystem security evaluation methods and the related directions. We classify the urban ecosystem security evaluation models into 12 types, and delineate their advantages, disadvantages and applicability. The urban ecosystem security evaluation indicators are classified into 7 types including biology, water, atmosphere, land, society, economy and population. Among these, a total of 33 commonly used evaluation indicators are selected for suggestions for future studies. We also analyze the substantial effect of each indicator on urban ecosystem security. Finally, we propose several potential directions for future research on urban ecosystem security.

Registration of unmanned aerial vehicle point clouds and terrestrial 3D laser scanner point clouds for irregular buildings

JING Haoran, XU Jinghai

2022, 0(6):  32-39.  doi:10.13474/j.cnki.11-2246.2022.0167.

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For towering irregular buildings, terrestrial 3D laser scanner are suitable for measurement and modeling. In practical applications, the terrestrial laser scanner is limited by the viewing angle, which will lead to the lack of point cloud models. Although the point cloud of UAV oblique photography is relatively complete, the bottom is poor and the accuracy is low. The two kinds of point cloud models are registered can perfect a single point cloud model. The difficulty of the registration is that the accuracy, density, coordinate systems and size of the two kinds of point cloud models are different, and they have a large angular deviation. For this difficulty, this paper discusses the registration process, introduces the registration parameters and calculation methods of the two kinds of point clouds, and selects the overlapping part of the two kinds of point clouds to divide the high-precision pieces, and selects the corresponding feature points to register the high-precision pieces. An irregular building, Tianbao Pavilion, is selected for experiments, and the proposed method is compared and analyzed to verify the effectiveness of the method in this paper.

Extraction of buildings with high-resolution remote sensing images based on U-Net3+ model

DOU Shiqing, ZHENG Hegang, XU Yong, CHEN Zhiyu, MIAO Linlin, SONG Yingying

2022, 0(6):  40-44.  doi:10.13474/j.cnki.11-2246.2022.0168.

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In response to the problems of low segmentation accuracy and blurred segmentation boundaries in traditional methods for extracting buildings from high-resolution remote sensing images, this paper proposes a semantic segmentation method for building features based on the U-Net3+ model. Firstly, on the basis of the U-Net network structure, the feature maps of different scales are fused using full-scale jump connection.Then, the feature expressions are learned from the multi-scale aggregated feature maps by deep supervision, and the cross-entropy loss function is used for training.Finally, different model parameters are tuned and tested according to the dataset characteristics to achieve the best segmentation effect. Experimental results show that the image segmentation accuracy and feature edge segmentation completeness based on the U-Net3+ model significantly improve in comparison with the U-Net and U-Net++ models, and the highest accuracy is achieved when setting epoch as 15 in all three models. Based on the U-Net3+ model, the segmentation accuracy of building features for high-resolution remotesensing images reaches 96.62% and the average intersection ratio of mIoU reaches 0.902 7, which reduces the phenomenon of missegmentation and omission, and reduces the model parameters, the model loss convergence rate is fast and the training period is shortened, and the extraction accuracy of buildings is significantly improved.

Research on automatic image segmentation based on vehicle-mounted point cloud feature

ZHONG Shaozhong, ZHOU Kejun, WANG Liuzhao, MAO Mingkai

2022, 0(6):  45-48 ,97.  doi:10.13474/j.cnki.11-2246.2022.0169.

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Through automatic extraction of on-board point cloud data, a large number of three-dimensional characteristic data can be quickly obtained. Using synchronous image data can not only improve the accuracy and efficiency of target interpretation, but also obtain the attribute information of the target object, which plays a very important role in production activities such as quality inspection, component attribute investigation and 3D modeling. In this paper, an automatic image segmentation technology corresponding to the feature data of vehicle-mounted point cloud is proposed. The relationship between the image and the feature information is judged by the position and attitude of the image, so as to realize the optimal image automatic selection and segmentation, generate the appropriate local orthographic image, and mark the correct position of the feature information in the new image.

A compound method for correcting vegetation information

LI Maolin, YAN Qingwu, ZHONG Xiaoya

2022, 0(6):  49-54142.  doi:10.13474/j.cnki.11-2246.2022.0170.

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Remote sensing technology can quickly obtain a large range of vegetation information. However, there exist some problems such as mixed classification of vegetation information. Therefore, a compound method for correcting vegetation information is established in the form of composite wavebands on the basis of spectral difference characteristics of ground objects. It is found that in terms of enhancing vegetation information, the method makes the information of high-cover vegetation information above 0.7, and alleviates the phenomenon of NDVI_rad over-saturation in high-cover vegetation. In terms of restraining non-vegetation features, the method separate vegetation from non-vegetation. making the information of most non-vegetation features information below zero. Additionally, in terms of anti-terrain, the method introduces δ/Red factor, reducing the impact of terrain on vegetation extraction to some extent.

An road synthesis extraction method of remote sensing image based on improved DeepLabV3+ network

REN Yuejuan, GE Xiaosan

2022, 0(6):  55-61.  doi:10.13474/j.cnki.11-2246.2022.0171.

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In the process of road extraction of complex scenes from remote sensing images, the shadows of trees and buildings as well as wasteland and open space are often interfered by many factors. In view of the problems of incomplete road information and loss of detail information in road extraction from DeepLabV3+ network model, this paper proposes a road extraction method of remote sensing image based on DeepLabV3 + network, which utilizes lightweight MobileNetV2 as the backbone network for feature extraction. The spatial pyramid pooling module is used to obtain multi-scale road information features to reduce the loss of details of road remote sensing images and improve the accuracy of road extraction. Experimental results of road extraction on the DeepGlobe dataset show that the proposed method can effectively reduce the computational complexity while ensuring that the accuracy is improved. In terms of pixel accuracy and intersection ratio, it reaches 79.7% and 64.3%, respectively, which are superior to DeepLabV3+ network and other classical network models, showing better road extraction ability.

Rural settlements extraction and spatial reconstruction based on GF-1

LUO Hong, LIAO Yu, YANG Cunjian

2022, 0(6):  62-65,92.  doi:10.13474/j.cnki.11-2246.2022.0172.

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In order to explore the spatial reconstruction strategy of rural settlements and help rural revitalization, We take Luojiang district of Deyang city as an example. Based on the remote sensing image data of GF-1 in 2018, we use object-oriented methods to extract settlement patch information, use nuclear density estimation to analyze the spatial distribution characteristics of rural settlements, and combine natural and socio-economic factors to construct the settlement land suitability evaluation system evaluates the existing rural settlements, and finally we propose a differentiated reconstruction strategy. The results show that:①The distribution of rural settlements presents the characteristics of "single-center multi-polar circle diffusion".② The suitability of settlement layout is generally high, with significant differences in suitability among different towns.③The layout of existing rural settlements tends to be higher-level suitable areas, and the more suitable the layout of towns and villages is more reasonable.④According to different agglomeration and suitability characteristics, the rural settlements in Luojiang district are divided into four types:agglomeration development type, construction promotion type, restricted coordination type, and ecological transformation type, and the direction of differentiation and reconstruction is discussed.

Study on sea ice albedo based on Sentinel-3 OLCI satellite data

DUAN Bokai

2022, 0(6):  66-70.  doi:10.13474/j.cnki.11-2246.2022.0173.

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Monitoring sea ice is a global task. The key process is to invert and model the surface albedo. Rather than widely used BRDF method, this paper focuses on a new direct estimation method (encoded in the SNAP tool). In this research, two scenes of OLCI datasets focusing on Utqiagvik with low cloud cover are applied and pre-processed through Rayleigh correction and IdePix cloud classification and produce rBRR bands and cloud layers. The two bands are processed in the snow processor together with OLCI TOA and outputted products, including spectral and broadband albedo. As a result, surface albedo products are compared with other albedo products derived from MISR & MODIS at the coastal sea area. The results suggest that the SNAP tool has overestimated the red-light albedo and underestimated the NIR albedo. Also, in-land ice-albedo is compared with tower-based albedo product at Utqiagvik baseline station. The result shows a very high accuracy of 95%.

Trigonometric leveling method assisted by micro air vehicle

ZHOU Jianguo, LUO Chao, PENG Duo

2022, 0(6):  71-75.  doi:10.13474/j.cnki.11-2246.2022.0174.

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For some non-line-of-sight areas which are blocked by hills and vegetation on elevation transfer routes, an UAV assisted trigonometric leveling method combined with the automatic tracking capability of robotic total station is proposed. The principle is that two robotic total stations with synchronized clocks take the 360° prism carried by an UAV hovering over the obstacles as the target for dynamic observation, and the height difference between the stations is calculated using synchronized observations. The main factors affecting the accuracy of the method and the countermeasures are analyzed, and the corresponding observation procedures are formulated. The actual test results show that the proposed method can obtain comparable height accuracy and is helpful for rapid height transmission in non-line-of-sight areas.

A robust 3D reconstruction method of UAV images

YU Guangrui, LIU Xingchun, SHI Chunlin, WANG Zhichao

2022, 0(6):  76-81.  doi:10.13474/j.cnki.11-2246.2022.0175.

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Aiming at the problem that traditional photogrammetry theory has high requirements for aerial photography conditions such as route planning, flight attitude and image overlap, yet unmanned aerial vehicle (UAV) has no obvious advantage of efficient support. Based on the theory of computer vision, a robust structure from motion(SFM) technique is proposed in this paper. Firstly, the matrix expression of the spatial rotation relation is transformed into the linear expression of the vector by using the rotation average method of Lie algebra. Then, before the least square adjustment, the L₁ norm is introduced to optimize the initial value iteratively to solve the global consistent rotation parameters. Finally, the coordinate system of displacement and rotation parameters are unified to realize the 3D coordinate calculation of matching points. The experimental results show that, the UAV image 3D reconstruction technology based on global SFM has higher accuracy than the traditional photogrammetry method, and the 3D point cloud reconstruction effect is better. The accuracy of point position measurement is better than 0.3 m under the beam adjustment aided by differential GPS station coordinates. Under different route layout conditions, the success rate of image solution is 100%.

Air-ground image fusion technology with point cloud registration

XIE Hong, CHEN Libo, NIE Qian, WU Wei, ZHANG Pei

2022, 0(6):  82-87.  doi:10.13474/j.cnki.11-2246.2022.0176.

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In order to achieve the high-precision fusion of air-ground images, a fusion method based on dense matching is proposed in this paper, and the result is compared with the fusion scheme using point cloud from aerial triangulation. Firstly, the three-dimensional point cloud is obtained by aerial triangulation and dense matching to the air-ground images. Then, the coarse registration of air point cloud and ground point cloud is performed by the SAC-IA algorithm based on 3DSC features. Finally, the refined registration is performed by the improved Point-to-Plane ICP algorithm, leading to the fusion of air-ground images.Compared with the sparse point cloud from aerial triangulation, the experimental results show that the dense matching point cloud can provide more robust registration result, and its accuracy is at centimeter-level.

Slope monitoring method based on machine vision in foggy weather

SHI Mengjie, TAO Tingye, GAO Fei, LI Jiangyang, CHEN Hao

2022, 0(6):  88-92.  doi:10.13474/j.cnki.11-2246.2022.0177.

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In order to solve the problem that the presence of fog will reduce the image quality and affect the monitoring effect in the process of slope monitoring by machine vision, so a slope monitoring method combining dark channel prior(DCP) is proposed. Firstly, by calculating the FADE value of the real-time image, which determines whether the collected image needs to be defogged. For images that need to be defogged, DCP algorithm is used for defogging processing to restore the texture details. Then, the scale-invariant feature transform(SIFT) algorithm is used to match the feature points of the image after fog removal, and the random sample consensus(RANSAC) algorithm is used to screen the excellent matching point pairs, and the transformation matrix between the template and the image is obtained. Then, the affine transformation is used to obtain the template coordinates and the slope displacement. The experimental results show that the proposed method performs well in fog images of different concentrations, and overcomes the problem that visual monitoring is difficult to apply in fog environment effectively.

The estimation of population on multi-spatial scale using Tencent location big data

LI Huimin, LUO Dawei, DOU Shiqing

2022, 0(6):  93-97.  doi:10.13474/j.cnki.11-2246.2022.0178.

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The diversity of social perception data brings new data and perspectives to the study of population estimation methods. In this paper, the multi-scale population spatial estimation is studied by Tencent location big data. With the volume data of construction land and residential area as the relevant factors, the 5 km grid is refined to 1 km and residential area level scale. By analyzing the correlation between Tencent location big data and demographic data at three different scales of Guangxi, Guilin and Lingui district, the spatial model of population at three scales is obtained by polynomial regression model analysis, and the correctness of the model is verified. The accuracy of the population estimation model is 0.984 5 on the scale of provincial level and 0.977 0 on the scale of city level, the verification accuracy is 0.979 9 in terms of community scale. The estimation results have high reliability.

Surface deformation and analysis of subsidence characteristics in typical mining cities by remote sensing

LAN Jinjing, QU Yiqiong, DU Weibing, GAO Xin, MA Dandan, ZHENG Yanchao

2022, 0(6):  98-103.  doi:10.13474/j.cnki.11-2246.2022.0179.

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Surface deformation is an important inducement and manifestation of geological disasters in mining cities. Taking Jiaozuo, a typical mining city as an example, this paper uses the SABS-InSAR method to construct a dense time series surface deformation SAR data set, and extracts the time series of the surface uplift or subsidence rate. The results show that the overall subsidence trend of this typical mining city is most obvious in the northeast of the surface subsidence, the maximum uplift rate is 51.20 mm/a, the maximum subsidence rate is 76.46 mm/a, and the average subsidence rate is 1.45 mm/a. Moreover, the distribution of ground subsidence is mainly located in the goaf area of coal mines, which provides a reference for the monitoring of large-scale ground subsidence in mining cities.

InSAR identification and cause analysis of landslide disaster in Ningxia (Xiji county) section of the Yellow River basin

XU Guanghe, HE Xiaofeng, WANG Guorui, HU Zhiyong, CHENG Xia, LI Xiaoqiong

2022, 0(6):  104-107.  doi:10.13474/j.cnki.11-2246.2022.0180.

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In view of the large-scale landslide risk, taking Ningxia (Xiji county) section of the Yellow River basin as the study area, this paper uses the permanent scatterer InSAR(PS-InSAR) technology to process the 18 Sentinel-1A satellite image data covering the area, obtains the radar line of sight deformation field in the study area from October 2019 to March 2021, and analyzes the deformation characteristics in the study area. The InSAR monitoring results are compared with the field survey results to verify the effectiveness of PS-InSAR method. The results show that the landslide deformation area identified by PS-InSAR may be related to the revival of old landslides induced by more precipitation in recent years.

Surface deformation monitoring and driving force analysis in Zhuhai city based on PS-InSAR technology

ZHU Bangyan, TANG Chao, REN Zhizhong, MA Zhuang, ZHANG Qi, LI Yun

2022, 0(6):  108-113.  doi:10.13474/j.cnki.11-2246.2022.0181.

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Land subsidence of Zhuhai city from October 2018 to November 2020 was retrieved by PS-InSAR using 63 Sentinel-1 images. The inversion accuracy is verified by GNSS ground observation data. The root mean square error of monitoring results is 4.58 mm, which showes high reliability for PS-InSAR to monitor land subsidence in study area. The spatial and temporal deformation characteristics of the surface deformation in Zhuhai city are analyzed, and the results show that the average deformation rate of the main part of Zhuhai city are between -55~15 mm/a. The main subsidence areas are distributed in the agricultural reclamation area and coastal port area around the Pearl river waterway. The main transportation lines, Zhuhai link of the Hong Kong-Zhuhai-Macau bridge and Zhuhai section of Guangzhou-Zhuhai railway, both of them have obvious deformation areas with average annual deformation rate of more than 20 mm/a, which need to be paid attention. Using geological conditions and groundwater exploitation data, the driving force of surface deformation in Zhuhai is analyzed. The results show that the ground subsidence rate in study area is positively related to the thickness of soft soil layer, and logarithmically related to the underground water level.

The LiCSBAS method considering atmospheric errors and phase unwrapping errors in the detection of geological disasters in alpine valley region

ZHOU Dingyi, ZUO Xiaoqing, XI Wenfei, XIAO Bo, LIU Xinyu

2022, 0(6):  114-120147.  doi:10.13474/j.cnki.11-2246.2022.0182.

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Aiming at the current time-consuming data preprocessing of time series analysis and the disadvantages of single-track detection of geological disasters in mountain and valley areas,this paper takes the mountain and valley areas along the Xiaojiang river in Dongchuan as the research object,using the time series LiCSBAS method and joint 2D deformation decomposition detect geological disasters in high mountains and valleys,explore the practical application of using LiCSAR products and GACOS products to solve the effects of excessive processing time,atmospheric delay control,and phase unwrapping error.The experimental results show that:①Using LiCSAR and GACOS products can greatly speed up the data processing efficiency and reduce the atmospheric delay on the image of the deformation results.②The loop closed phase can effectively identify the problematic loop with the root mean square value greater than the defined threshold.③The 1D line-of-sight deformation obtained by the joint lifting rail is divided into two dimensions to obtain the vertical and east-west deformations. The information of various deformations is integrated,and high-resolution optical images are introduced to detect a total of 6 geological disaster areas. The accuracy and advantages of this method in the detection of geological disasters in mountain and valley areas are verified,and which provides an effective and rapid detection method for government departments to monitor and detect the occurrence of geological disasters in mountain and valley areas.

Potential landslides deformation monitoring in Bijie city with InSAR time series

ZHANG Jiayong, ZOU Yinxian, LIU Qianyun, ZHANG Nan, GONG Wei, LI Kanglun

2022, 0(6):  121-124.  doi:10.13474/j.cnki.11-2246.2022.0183.

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Guizhou province is one of the provinces with frequent and most serious geological disasters in China, featured with strong concealment, abruptness and unpredictability. In order to strengthen the monitoring and evaluation of potential landslides in Nayong and Qianxi county, the surface deformation of Nayong and Qianxi county are obtained using Sentinel-1 SAR data from March 2017 to July 2020 and SBAS-InSAR technology. The results show that a total of 60 suspected landslide locations are found in the study area, and the maximum cumulative deformation variable of landslide is up to 23 cm in the monitoring time. Through the field survey of landslide locations in the study region, it shows that this method can provide reference for the prevention and management of geological disasters in Guizhou province.

Rapid estimation of rural homestead area in Western China based on UAV imagery and object-oriented method

LIU Yaohui, YU Xianghui, FAN Jiejie, ZHOU Jie, CHENG Hao, YAO Guobiao, MENG Fei, JIN Fengxiang

2022, 0(6):  125-129.  doi:10.13474/j.cnki.11-2246.2022.0184.

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Rapid and accurate extraction of rural homestead area is of great significance for urban and rural planning, housing and land integration, and beautiful rural construction. In this paper, one village in Shaanxi province is taken as the research area. Based on UAV high-resolution remote sensing data, multi-scale segmentation and supervised classification are used to extract the building contour. The number of building floors is then estimated based on oblique photogrammetry. Finally, a fast estimation of homestead area is carried out. The overall accuracy of building extraction in the study area is 95.8%, and Kappa coefficient is 0.892 5. The total area of residential land in the study area is 36 417 m². The results show that this method can accurately and effectively extract the homestead area, and provide a reference for UAV remote sensing in the extraction and identification of buildings and the rapid determination of homestead area.

Acalibration method considered incidence deviation for terrestrial laser scanner

ZHANG Dexian, XIAO Haowei, WANG Jianglin, YANG Liyang

2022, 0(6):  130-136.  doi:10.13474/j.cnki.11-2246.2022.0185.

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There may be incident deviation in the ranging signal of the ground laser scanner, so that the incident vector and the rotation axis of the rotating reflector are not parallel to each other, and the resulting point cloud error diverges with the distance. This error cannot be calibrated by using the traditional total station systematic error model. Therefore it is necessary to consider the incident deviation of ranging signal as the system error of scanner. In this paper, a systematic error model for the ground laser scanner considering the incident deviation was introduced, and the corresponding systematic error parameter estimation method are proposed,which together constitute the calibration method of ground laser scanner. The formula derivation shows that the traditional total station systematic error model is a special case of the method in this paper. The experimental results show that compared with the traditional total station calibration method, this method reduces the closure error from 8 cm to 1 cm.

Monitoring surface subsidence and driving factors in Xining city using SBAS-InSAR

ZENG Xuehong, ZHAO Yihua

2022, 0(6):  137-142.  doi:10.13474/j.cnki.11-2246.2022.0186.

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Surface subsidence has the characteristics of time persistence and spatial expansion. The spatio-temporal characteristics of surface subsidence with time series, wide coverage and high accuracy prevent the potential harm caused by surface subsidence. This paper utilizes SBAS-InSAR and Sentinel-1A images (from April 2017 to February 2021) to monitor surface subsidence in Xining city. The results suggest that the surface deformation in Xining city has the trend of stable urban deformation, obvious local regional subsidence and slow uplift. The subsidence rate of three obvious subsidence areas (subsidence area Ⅰ in the east of the city, subsidence area Ⅱ in the west of the city and subsidence area Ⅲ in the north of the city) is approximately 20~35 mm/a. The driving factors of the subsidence are attributed to the collapsible loess stratum in the subsidence area, which has the bearing characteristics of fragile soil structure. Under the combined action of the self-weight stress of the covering soil layer and the additional stress of buildings. After the soil is soaked by water, the structural performance of the soil is rapidly damaged. The soil layer will have significant additional subsidence, and its strength will be rapidly reduced, so as to cause uneven subsidence of buildings.

Application of multi-source data in 3D reconstruction of buildings in complex scenes

XIE Yuan, DONG Meng, MA Xinjian

2022, 0(6):  143-147.  doi:10.13474/j.cnki.11-2246.2022.0187.

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With the development of digital city construction, more and more complex large buildings need to complete 3D modeling. For the irregular and complex buildings, the traditional total station data acquisition method is more cumbersome and laborious. In this paper, the ground laser scanner is used to obtain the point cloud data inside and outside a large building, and the close range photogrammetry is used to obtain the orthophoto map of the top of the building. The site photos are taken at the small components, and the point cloud registration, denoising, image processing geometric modeling and texture mapping process are carried.Finally the 3D reconstruction of large buildings is completed, and the key technology is researched in the process.

Analysis of climate suitability pattern and influencing factors of human settlements in the three provinces of Northeast China based on GIS

GAO Jiaji, LI Hongkui, BAI Zhizhen, YANG Jun

2022, 0(6):  148-153.  doi:10.13474/j.cnki.11-2246.2022.0188.

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The climate comfort of the human settlement is an important criterion for judging whether a certain area is livable or not. Using meteorological data and climate comfort model from 1988 to 2018, reveal the differences and influencing factors of the climate comfort of human settlements in the three provinces in Northeast China. The results show that:①The climate of the human settlement is relatively comfortable from June to August, and the comfort level is the lowest from January and February. The difference in comfort space in the summer half year is greater than that in the winter half year. The comfort level in the two phases of 1988-2002 and 2003-2018 is generally good, and there are two low-value centers. In terms of seasonal changes in comfort, spring, summer and autumn show an overall increasing trend, while winter shows a worsening trend. The spatial distribution can be divided into 5 categories. The characteristics of categories are warm and wet comfort, warm and dry and more comfortable, cold and comfortable, dry and less comfortable, and dry and uncomfortable. ②The main influencing factors are temperature and wind speed in summer and winter. Air quality and urban development level are positively correlated with climate comfort of human settlements, but weakly positively correlated; the relationship between vegetation coverage and the level is phased.

Research and practice on marine spatial data integration based on Guangdong territory spatial planning“one map” implementation supervision information system

LIU Chunshan, ZENG Yuanwu, LUO Hongming, CHENG Yingxuan, ZHONG Xiaojun, ZHANG Tonghui, YUE Wen

2022, 0(6):  154-157.  doi:10.13474/j.cnki.11-2246.2022.0189.

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Based on the data aggregation results of Guangdong territory spatial planning "one map" implementation supervision information system(called planning "one map" system),the research of marine spatial data integration is conducted by data screening, boundary fitting,classifier combination,and data governance.Moreover,the process and rules of data integration are taken shape during the research which will support building the database and conducting of marine resources inventory survey by using the planning "one map" system.

Discussion on some problems in teachingon-line about surveying course

PENG Cheng, LI Xiaoli, ZHANG Chunju, ZHOU Zhiyi

2022, 0(6):  158-161.  doi:10.13474/j.cnki.11-2246.2022.0190.

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Teaching on-line is a necessary stage for the development of digital teaching to intelligent teaching. Today, teaching on-line has become a normal and main way with covid-19 epidemic prevention and control. This paper discusses some problems existing in the Surveying course of teaching on-line, and puts forward some ideas to solve these problems, so as to provide reference for the Surveying course construction.

Pedagogical design and reflections of teaching principles and methods of geographic information system in English

WANG Tao, LI Xiaojuan

2022, 0(6):  162-165.  doi:10.13474/j.cnki.11-2246.2022.0191.

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Principles and methods of geographic information system (GIS) covers theories and implementing techniques about geospatial data processing, management, query, analysis, and visualization.It is one of the basic compulsory courses for undergraduate in geomatics, surveying and mapping, geographic science, and other geo-related disciplines.In recent years, more and more undergraduates continue their academic life by applying for master degrees.On the other side, employers give more opportunities to students with global competencies.Both trends together with other factors push educators to think and implement high standard international education in which teaching courses in English is a crucial component.After reviewing the pros and cons of teaching STEM courses in English, this paper proposes pedagogical guidelines and goals for principles and methods GIS, which is on the list of national courses of excellence.Structure of the course contents and delivering approaches are extended to adapt to students of various background.In the post epidemic era, teaching GIS in English is going to be more important since that GIS is a unique vehicleto deliver Chinese voice, Chinese stories, and Chinese solutions by students with cross culture and cross language capabilities.

Application of 3D laser scanning technology in subway tunnel completion survey

LI Xu

2022, 0(6):  166-169.  doi:10.13474/j.cnki.11-2246.2022.0192.

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This paper discusses the application of 3D laser scanning solution based on Trimble TX8 3D scanner, Trimble SX10 3D scanner and Trimble RealWorks (TRW) and Trimble Business Center (TBC) software in metro tunnel completion survey. The operation scheme based on SX10 has the advantages of high data processing efficiency and more reliable data accuracy. The operation scheme based on TX8 has the advantages of high point cloud density and less demand for the number of CPⅢ control points. Compared with the traditional operation mode based on total station, the two operation schemes proposed in this paper greatly improve the operation efficiency and data quality, and ensure the traceability of data. Combined with the acceptance survey project of a subway tunnel in Guiyang, this paper verifies the practicability of the method and effectively popularizes the application of 3D laser scanning technology in the field of precision engineering survey.

Application of UAV tilt photography technology in slope monitoring

WAN Zhongming, WANG Yawen, FAN Ziyi

2022, 0(6):  170-172.  doi:10.13474/j.cnki.11-2246.2022.0193.

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With the in-depth development of open-pit mine,more slopes have been produced,which further increases the risk of landslide and collapse. Therefore,the deformation detection and stability analysis of slope is also a very important work in mine safety production. As a fast,simple and safe image acquisition technology,UAV tilt photogrammetry has been studied in the field of geological survey and so on. In this paper,UAV tilt shooting technology is used to realize slope inspection and replace or assist manual inspection,so as to ensure the work safety of inspectors,find and deal with the potential risks of mine slope in time.