Table of Content

25 October 2021, Volume 0 Issue 10

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Building the “intelligent brain” of the Yellow River to serve the ecological protection and high-quality development of the river basin

WANG Jiayao, QIN Fen, GUO Jianzhong

2021, 0(10):  1-8.  doi:10.13474/j.cnki.11-2246.2021.297

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This paper firstly introduces the basic background of the Yellow River Basin, such as the hydrological, geographical landscape and geomorphic characteristics, the history and ecological management of the downstream river and estuary changes, and the historical flood and drought disasters of the Yellow River Basin, and analyzes the main problems and advantages of the ecological protection and high-quality development of the Yellow River Basin. Then, it focuses on how the "intelligent brain" of the Yellow River serves the protection and development of the river basin, puts forward the three elements of the "intelligent brain" of the Yellow River, namely the perception system (intelligent perception network integrated with heaven and earth), the storage management system (resource pool) and the operating system (space-time big data platform), and discusses the composition and basic functions of the river basin integrated space-time big data center. Considering spatial-temporal big data platform and its objectives and requirements, this paper analyzes and puts forward the technical system and construction technology of hybrid spatial temporal big data platform based on grid integration and elastic cloud, proposes the application conceptual model of "common spatial temporal big data platform +" and its specific application mode, and discusses the service of spatial-temporal big data platform for urban digitization, networking and intelligence in the Yellow River Basin. In order to strengthen the new smart city construction of the seven urban agglomerations in the upper, middle and lower reaches of the river basin, and promote the ecological protection and social and economic development of the river basin, this paper proposes to build a comprehensive scientific and technological information consulting service platform based on the river basin space-time big data platform to serve the protection and development, thus supporting the construction of the river basin collaborative innovation community and enhancing the integrity and collaborative development of the river basin.

Coupling coordination analysis of urbanization and eco-environment in Ningxia based on DMSP-OLS and MODIS data

ZHAO Jinlong, ZHAO Hui

2021, 0(10):  9-14,27.  doi:10.13474/j.cnki.11-2246.2021.298

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A scientific understanding of the coupling and coordination mechanism between urbanization and eco-environment is of great significance for promoting the ecological protection and high-quality development in the Yellow River Basin and the areas where the Yellow River passes. In this study, Ningxia Hui Autonomous Region is taken as an example and a long-time sequence of DMSP-OLS nighttime light data is used to establish an urban nighttime light index (UNLI). A method of constructing remote sensing ecological index (RSEI) for large regional scale is proposed by using MOD09A1 and MOD11A2. On this basis, the coupling coordination degree model (CCDM) is used to analyze the development process of urbanization and eco-environment of five prefecture level cities in Ningxia from 2000 to 2012. The results show that:①The UNLI of Ningxia is significantly correlated with GDP per capita, primary, secondary and tertiary industries (p<0.001), which can better reflect the level of urbanization. ②The RSEI based on MOD09A1 and MOD11A2 can better reflect the temporal and spatial variation characteristics of Ningxia ecological environment quality. ③The coupling coordination degree of urbanization and eco-environment of Ningxia show a steady upward trend. Ningxia is in the transformation stage of basic coordination and lagging eco-environment. The results have important reference value for ecological protection and high-quality development of cities along the Yellow River.

Analysis on the harmonious mechanism and coupling coordinated development of urbanization and ecology in the influenced area of the low Yellow River

ZHANG Pengyan, BAI Jiawei, RONG Tianqi, ZHU Huiru, ZHANG Jinbing, LIU Zhenyue, LOU Yuanyuan, WANG Qianqian, ZHOU Zhimin

2021, 0(10):  15-19,33.  doi:10.13474/j.cnki.11-2246.2021.299

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Through the double evaluation of harmony degree and coupling degree, and using the harmony degree model, coupling coordination degree model and coordinated development degree model, this paper studies the temporal and spatial change law of the coupling level between urbanization and ecological environment in the influenced area of the low Yellow River from 2005 to 2018. The results show that:①On the whole, the regional coupling level shows the change law of falling first and then increasing. The coupling relationship belongs to the transition stage from running-in to high-level coupling, and the development of urbanization lags behind the ecological environment. ②The influenced area of the low reaches of the Yellow River forms a highly coupled aggregation area with Zhengzhou and Jinan as the core, and shows the spatial aggregation and spillover effect of first accumulation and then radiation diffusion.③At present, the urban economic development in the study area makes a great contribution to the coupling level, and the comprehensive impact of urban development on the ecological environment has no obvious negative tendency at the present stage.

A study on space-time coupling relationship between nightlight data and the indicators of social and economic development in the Yellow River Basin

ZHANG Yuansheng, CAO Zhiwei, WEI Wei, HU Jie

2021, 0(10):  20-27.  doi:10.13474/j.cnki.11-2246.2021.300

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Through the correction and processing of the national nightlight data from 1992 to 2013, this paper obtains the national and watershed nightlight data images, conducts economic spatial aggregation analysis, compares and analyzes the relevant factors. The results show that the areas with high economic spatial aggregation are distributed near the Yellow River channel, from the upper reaches to the lower reaches of the Yellow River, the heat intensity is gradually increasing, and the provincial capital city is the core area, spreading outwards, showing the tendency of the polymerization area to disperse to the surrounding area under the condition that the polymerization of the old polymerization point is intensified. The basin development index BDI has a certain correlation, the overall trend of nightlight data in 9 provinces of the basin is basically consistent with the change trend of the national nightlight data, showing a steady upward trend, but the overall value is lower than the national nightlight data, the high-quality development of the Yellow River Basin is imminent.

Spatio-temporal evolution pattern of wetland landscape in the Yellow River Basin

LI Heying, ZHANG Jianchen, GUO Jianzhong

2021, 0(10):  28-33.  doi:10.13474/j.cnki.11-2246.2021.301

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The study on the spatio-temporal evolution of wetland landscape is an important reference for the follow-up wetland ecological restoration and protection. This paper uses the land using data of the Yellow River Basin from 1980 to 2015 to construct the wetland vector data set in the Yellow River Basin, and analyzes the spatio-temporal evolution characteristics of the wetland in the Yellow River Basin quantitatively and qualitatively based on the landscape metrics. The transfer matrix is used to calculate and analyze the transfer type and quantity of wetland resources in each two periods. The research results shows that:①From 1980 to 2015, the wetland rate of the Yellow River Basin was 3.5%, in which the natural wetland rate was about 2.0%, which means that the wetland type of the Yellow River Basin is mainly natural wetland. ② The results of patch area showes that the total area of wetland in the Yellow River Basin is decreased by 312.74 km², represented by the constructed wetland increased and the natural wetland decreased. The marsh wetland increased in natural wetland, mainly in 2005-2010, increased by 979.22 km², and the beach decreased by 1 218.19 km², mainly occurred during 1990-1995 and 2005-2010. The results of PD showes that the degree of patch fragmentation increases gradually with the increase of human activities. The results of LPI show that paddy field is the dominant wetland type in the Yellow River Basin, swamp and lake are the dominant wetland types in the natural wetland. ③ The transformation between wetland type and others is the main component of landscape transformation in the Yellow River Basin, in which marsh and floodplain are the main transferred types with others.

Vegetation coverage change remote sensing monitoring of the middle and lower reaches of the Heihe River

HU Jie, JIANG Chengzhen, YANG Yong, HE Xiaofeng, LI Kai

2021, 0(10):  34-38.  doi:10.13474/j.cnki.11-2246.2021.302

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After the national decision to conduct the unified water resource regulation in 2000, the ecological environment in the middle and lower reaches of the Heihe River is improved. However, an objective and impartial ecological environment evaluation method is lacked. Because of the large area and little data in the middle and lower reaches of the Heihe River, the method to calculate vegetation fractional coverage (VFC) by extracting normalized difference vegetation index (NDVI) during growing season from satellite remote sensing images is proposed, and the spatial distribution, area proportion and trend of VFC are analysed. This research finds that there is a transformation from low-cover vegetation to other types of vegetation in the middle and lower reaches of the Heihe River during 2000 and 2017. Besides that, the area of high-cover vegetation increases and the overall vegetation coverage is good. The conclusion is consistent with the ecological environment change in the middle and lower reaches of the Heihe River, which proves that the proposed method is reliable to assess the regional ecological environment.

Spatial distribution of air pollutants in the middle reaches of the Yellow River Basin in winter 2015-2019

WANG Weisi, MA Qingxia, ZHANG Jianchen, LI Guangjia

2021, 0(10):  39-47.  doi:10.13474/j.cnki.11-2246.2021.303

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Based on the six air pollutants concentrations in the middle reaches of the Yellow River Basin (Shanxi section and Shaanxi section) in the winter of 2015-2019, this paper studies the variation characteristics of air pollutants in the middle reaches of the Yellow River Basin in winter. The results show that the concentrations of PM₁₀ and CO in the middle reaches of the Yellow River Basin decrease continuously from 2015 to 2019, and the O₃ concentration continues to increase, and the average concentrations of PM_2.5, SO₂ and NO₂ increase firstly and then decrease. The concentrations of NO₂, CO, PM_2.5, PM₁₀ and SO₂ are the lowest in 2019. The average concentration of O₃ is the highest in winter of 2019 (54 μg/m³). The concentration of PM_2.5 in the lower reaches of the study area is higher than that in the upper reaches, and gradually increases from north to south along the Yellow River. The concentration of PM_2.5 in the Shanxi section of the east side of the Yellow River is higher than that in the Shaanxi section of the west side. The spatial distribution of PM₁₀ concentration in the study area changes from high in the East and low in the west of the Yellow River in 2015-2016 to low in the upstream and high in the downstream in 2017-2019. The concentration of SO₂ in the east bank of the Yellow River is higher than that in the west bank. The high NO₂ value region change from the lower west of the Yellow River in 2015-2017 to the middle and upper reaches of the Yellow River in 2018-2019. The high CO concentration area is located in the lower reaches of the east side of the Yellow River. The spatial distribution of O₃ concentration is not obvious, but the concentration increases significantly in recent five years. So we need to strengthen the monitoring and prevention of ozone in the future.

Spatio-temporal characteristics of air pollutants in major urban agglomerations of the Yellow River Basin

ZHAO Pengfei, BAI Yang, WANG Pan, WU Peiqing

2021, 0(10):  48-53.  doi:10.13474/j.cnki.11-2246.2021.304

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To explore air pollutants' temporal and spatial evolution characteristics in the Yellow River Basin, we analyze the annual, seasonal, and monthly changes of the concentrations of OMI HCHO, NO₂, and SO₂ in seven major urban agglomerations from 2005 to 2019. High concentration areas of the three pollutants concentrated in Shandong Peninsula Urban Agglomeration (SPUA), Zhongyuan Urban Agglomeration (ZYUA), the southern part of Jinzhong Urban Agglomeration (JZUA), and eastern part of Guanzhong Plain Urban Agglomeration(GPUA). The HCHO column troposphere concentration showes a fluctuating upward trend from 2005 to 2019 in seven urban agglomerations. Its monthly variation showes a single peak structure, high in summer, low in winter, and much the same in spring and autumn. The NO₂ troposphere column concentration showes an upward trend from 2005 to 2011 and only slightly decreased in 2008. It begins to decline significantly in the Hubao-Eyu Urban Agglomeration (HEUA), Ningxia along the Yellow River Urban Agglomeration (NYUA), and JZUA from 2011 due to the implementation of the Emission Standard of Air Pollutants for Thermal Power Plants (GB 13223-2011), while SPUA (with a slight decrease in 2012), ZYUA, and GPUA due to the Air Pollution Prevention and Control Action Plan from 2013. Its monthly variation of the seven urban agglomerations showes an upward parabola where the higher the concentration, the more pronounced the unimodal structure, high in winter, low in summer, and much the same in spring and autumn. The SO₂ column concentration reaches the peak in 2007, begins to decline sharply in 2008, and showes a fluctuating downward trend after 2010. Its monthly and seasonal variations are similar to that of NO₂. The air quality of Lanzhou-Xining Urban Agglomeration, NYUA in the upper reaches of the Yellow River Basin, and HEUA at the junction of upper and middle reaches are better than the GPUA and JZUA in the middle reaches. The air quality of ZYUA at the intersection of the middle and lower reaches and SPUA at the lower reaches is inferior.

3D laser scanning point cloud analysis method for dam deformation monitoring

YANG Chuanxun, YANG Ji, LI Yong, HAN Liusheng, CHEN Shuisen

2021, 0(10):  54-59.  doi:10.13474/j.cnki.11-2246.2021.305

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Deformation monitoring is an important part in dam safety monitoring. With the development of 3D laser point cloud technology, it is a trend to use this kind of tech in dam deformation monitoring, but the current algorithm constraints and data processing uncertainty errors greatly affect the monitoring accuracy. Based on this research, a point cloud data registration algorithm based on normal distribution, improved original progressive encryption triangulation filter algorithm, and point-to-face variable comparison analysis mode are used to monitor dam-shaped variables, and source program development is realized. Monitor point cloud data processing, comparative analysis, and modeling processing.The results show that:①The improved algorithm has high efficiency and excellent precision, and is suitable for dam point cloud data processing and comparative analysis. ②The developed point cloud data integration processing software is simple and easy to use, and can accurately reflect the deformation of the dam. ③Huanglongdai dam is stable, there is no safety hazard.

Urban road extraction based on multi-source data

DENG Kai, YANG Cancan, YIN Li, ZHAO Mingwei, JIANG Ling, PENG Daoli

2021, 0(10):  60-66,82.  doi:10.13474/j.cnki.11-2246.2021.306

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The high-accuracy extraction of urban roads can provide data basis and support for many fields, for instance, three-dimensional urban expression, urban terrain analysis, urban construction planning and traffic navigation. Comprehensively combining the advantages of open source road network, street-view images and remote sensing images, and taking the part of Hefei city as the experimental area, an extraction approach for urban road is proposed. Firstly, the maximum likelihood method is used to extract the urban road. Secondly, the void is filled and the connecting areas that does not belong to the urban road are divided by using the open source road network and street view data. Thirdly, the missing parts caused by cover, like vegetation, are disposed of via the width of each road which measured by street view. Finally, the intersections of urban road are improved. Spatial analysis, statistical analysis, geometric measurement, least square fitting methods are involved in the process. To assess the performance of the proposed method, the precision of urban road extraction is evaluated and analyzed. The experimental results indicate that the urban road extraction method proposed in this paper can extract urban road with high precision and the extraction precision is 96.65%, Kappa coefficient is 93.71% and the standard deviation of road width is 0.03 m. In particular, it can improve the incomplete information extraction caused by different spectrum of the same object, different object with the same spectrum and the problem of cover.

Block filtering method for LiDAR point cloud fusion image

MAO Donghai, LI Shoujun, WANG Feng, DAI Huayi, YANG Fanlin

2021, 0(10):  67-72,131.  doi:10.13474/j.cnki.11-2246.2021.307

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Aiming at the problem that the existing LiDAR ground point filtering algorithm is not adaptable to complex terrain and objects, a block filtering method combining point cloud and ground image is proposed in this paper. Firstly, the ground image is matched with the point cloud to make it obtain more spectral texture information from the image. Secondly, the ground feature spectrum, forest land relative density, point cloud elevation characteristics, DSM model and its slope are fully analyzed, and the original point cloud is cut into several independent blocks based on decision-making level fusion. Finally, according to the different multivariate detail characteristics of each region, the IPTD filtering algorithm is improved and the parameters are optimized by the search method to obtain the optimal and robust results. Using the filtered total ground points, the DEM model obtained by interpolation algorithm and related experiments verify the superiority of the proposed algorithm.

Multi-feature collaborative extraction of canopy coverage in building area for geographical condition monitoring

CHEN Genliang, DONG Shengguang

2021, 0(10):  73-77.  doi:10.13474/j.cnki.11-2246.2021.308

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In view of the new task of extracting canopy cover in national geographic condition monitoring work, through in-depth study and analysis of spectral and texture characteristics of main ground features in housing construction area, the normalized vegetation index (NDVI), contrast and entropy are used as judgment rules. According to the idea of object-oriented, an extraction method of canopy coverage in building area based on high-resolution remote sensing image is designed. The experimental results show that the method can automatically extract the canopy coverage of the building area, greatly reduce the workload of the current common visual interpretation methods, and can effectively distinguish other ground features in the building area with similar spectral characteristics of canopy coverage compared with using a single image feature.

An algorithm for eliminating mismatching point pairs of BRISK features in UAV images

HE Zhiwei, TANG Bohui, WANG Tao, WANG Xiaohong, YU Bohua, LI Chuang, DENG Shixiong

2021, 0(10):  78-82.  doi:10.13474/j.cnki.11-2246.2021.309

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In view of the high redundancy and poor globality of the same-name point pairs when the BRISK feature detection algorithm matches in remote sensing images, this paper considers that the BRISK feature detection algorithm can obtain a large number of UAV image feature points, and the Delaunay triangulation algorithm can use the rough matching point pairs of the BRISK feature points of the image construct a triangulation network. Combining the advantages of the two algorithms, a method combining the BRISK feature detection algorithm and the Delaunay triangulation algorithm to eliminate mismatched point pairs of UAV images is proposed. This method uses the BRISK rough matching feature points of the two images to construct the Delaunay triangulation, uses the triangle similarity in the traversal of the two images to eliminate the mismatching point pairs, and then uses the photographic invariant principle to further eliminate the wrong matching point pairs, improving the accuracy of the image matching. This paper compares and studies the effect of the projective invariant algorithm of Delaunay triangulation and the RANSAC algorithm to eliminate the original image group, adds the pepper-salt noise image group and the rotated image group to the effect of the BRISK feature mismatch point pairs. The experimental results show that the three sets of images respectively use the UAV remote sensing image matching method combining the BRISK feature and the Delaunay triangulation's projective invariant algorithm to obtain the correct feature matching points with low redundancy and excellent global performance.

Automatic high precision registration of terrestrial LiDAR point cloud and digital image

HU Chunmei, XIA Guofang, LIU Xi

2021, 0(10):  83-87.  doi:10.13474/j.cnki.11-2246.2021.310

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In order to solve the problem of automatic registration of non-homologous and heterogeneous data of ground LiDAR and digital optical image, this paper proposes a method of high-precision automatic extraction of homonymous features based on mutual information. Firstly, the reflection intensity image and the color image based on RGB information of the central plane projection are generated from the point cloud data, and the coarse registration parameters of the point cloud and the image are determined by the matching of the color image of the point cloud and the digital optical image. Then, the feature of the reflection intensity image is extracted, and its initial position on the digital optical image is determined by coarse registration parameters, and the high-precision matching of non-homologous data is realized by mutual information. Finally, Rodrigues matrix and weight selection iterative method are used to calculate the high-precision registration parameters and generate the three-dimensional color model. The experimental results show that this method can solve the registration problem of non-homologous and heterogeneous data for the terrestrial LiDAR point cloud and digital optical image, which has certain research and application value.

Assessing the L5 positioning performance of IRNSS and QZSS in their primary service areas: stand-alone and combined with GPS

QIAN Wenjin, ZHANG Lin, ZHANG Zelie, ZENG Pan, JIANG Ziwei, QU Xiaowen

2021, 0(10):  88-93.  doi:10.13474/j.cnki.11-2246.2021.311

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The Indian Regional Navigation Satellite System (IRNSS) and Quasi-Zenith Satellite System (QZSS) are two Regional Navigation Satellite Systems (RNSSs) announced as fully operational in recent years. In this contribution, stand-alone L5 single point positioning (SPP) performances of IRNSS and QZSS are first assessed in their primary service areas. Then, the performance of each RNSS assisting GPS positioning with satellite cut-off elevation angles set at 5°, 15°, 25°, 35°, 45°, and 55° in its primary service area is compared and analyzed in detail. It is to examine to what extent the constellation configuration difference can affect the performance of each RNSS assisting GPS positioning in the urban canyon environment. The results demonstrate that:① IRNSS can provide 24-hour continuous independent L5 positioning service with a positioning accuracy of <2.50 m in horizontal, and <4.10 m in vertical in its primary service area; ② QZSS can only provide independent L5 positioning service of limited availability with a positioning accuracy of <4.80 m in horizontal, and <7.40 m in vertical in its primary service area; ③ the performance of QZSS assisting GPS positioning in the urban canyon environment in mainland Japan is better than that of IRNSS in its primary service area, especially in the situation of a limited sky view, due to its unique constellation configuration. The finding of this study could inspire the policy-makers when they are designing a new RNSS.

Influence analysis of transmission line electromagnetic interference on BDS data quality and accuracy

FENG Zhiqiang, ZHANG Yaodong, HU Danhui, ZHOU Guangyuan, LI Zhaohui, ZHOU Xueming, MAO Xiaopo

2021, 0(10):  94-97,113.  doi:10.13474/j.cnki.11-2246.2021.312

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China's self-developed BDS satellite navigation system is now completed. In addition to the traditional surveying and mapping field, BDS is now popularizing in various industries and applications. Aiming at the application of transmission line geological hazard monitoring, this paper explores the influence of transmission line electromagnetic environment on BDS satellite monitoring from two aspects:data quality and positioning accuracy. 23 days BDS observations under strong and no electromagnetic interference is applied into study. The analysis results of BDS monitoring data of 500 kV transmission line for 23 days show that the difference of data integrity rate is less than 1%, the multipath effect difference is less than 0.1 m, the signal-to-noise ratio difference is less than 0.3 dBHz, the cycle slip ratio difference is less than 150, and the relative positioning accuracy difference is less than 5%. In general, the influence of transmission line electromagnetic interference on the BDS data quality and positioning accuracy is not significant.

An improved method of the non-contact measuring method of bridge deflections based on monocular vision

LIU Shaoping, YANG Yongbo, ZHANG Dongsheng, ZHAO Fang, ZOU Yu

2021, 0(10):  98-102.  doi:10.13474/j.cnki.11-2246.2021.313

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On the basis of the existing monocular vision measurement,an algorithm about real pitch angle calculation is proposed, combined with an image fast correlation matching and positioning algorithm,which can complete the rapid and accurate measurement of the bridge deflection.Through the accuracy verification test and the deflection comparison test, the corresponding results are obtained.The results show that:①The general deflection measurement method which does not consider the real pitch angle change of the target point has a large error in the measurement result which is far away from the center of the field of view. ②The measurement results of monocular vision method are consistent with the vertical downward rigid body displacement of Angle steel. ③The monocular vision method is basically consistent with the deflection curve variation trend and measurement value measured by GPS, the feasibility and accuracy of the proposed method for monitoring bridge deflection are fully verified. It can provide reference for the research of civil engineering deformation measurement technology based on digital image correlation method in the future.

Research on geographic information dissemination mode in omnimedia era

ZHANG Sujin, FU Yao, JIANG Lijiao, ZHAO Fei

2021, 0(10):  103-107.  doi:10.13474/j.cnki.11-2246.2021.314

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With the arrival of the omnimedia era, the audience's identity has been reconstructed. The lowering of the threshold of information dissemination allows the public to truly participate in the dissemination of information. Geographic information, as a branch of information, is bound to change in the tide of the omnimedia era. From the perspective of dissemination, we first analyze the changes of geographic information dissemination mode.Secondly based on the dissemination theory of information, a de-centralized and radiation diffusion dissemination mode in the omnimedia era is constructed. Then combined with the characteristics of omnimedia, this paper studies the dissemination characteristics of geographic information from the aspects of communication subject, content, form, audience and mode.And we finally study the current situation and existing problems of geographic information communication.

Evaluation of the credibility of multi-source address elements: a case study of road feature

SUN Licai, CHEN Yisong, XIONG Jie, LUO An, WANG Yong

2021, 0(10):  108-113.  doi:10.13474/j.cnki.11-2246.2021.315

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With the development of spontaneous geographic information and Chinese address element segmentation technology, the quality of address elements needs to be evaluated. Aiming at the problem that the quality of address elements produced by Chinese address text segmentation is difficult to effectively evaluate, this paper proposes a method for evaluating the credibility of address elements supported by multi-source data and network retrieval. Firstly, the Chinese word segmentation tool is used to segment the address elements and part-of-speech tagging. By analyzing the word frequency and part-of-speech combination mode, the credibility of the naming structure of the address elements is calculated. Then, based on large-scale address samples, road data, and POI data, excavate the data support of multi-source data to address elements, and calculate the data support. Then use the search engine to retrieve the address elements quickly, analyze the search results and quantity, and calculate the network credibility of the address elements. Finally, a comprehensive credibility calculation model for address elements is proposed to realize the comprehensive credibility calculation of address elements. Experimental results show that the model and method can not only efficiently and quickly calculate the credibility of address elements in Chinese address texts, but also effectively discover the remoteness and falsehood of address elements, which provides a reference for the automatic detection and standardization of address elements.

Accuracy evaluation and efficiency analysis of Heron mobile backpack 3D laser scanning system in 1: 500 large scale mapping

ZHAO Yangang, FU Shoujian, CHEN Hongqiang, WU Bo

2021, 0(10):  114-116.  doi:10.13474/j.cnki.11-2246.2021.316

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In the past two years, backpack 3D laser scanners based on SLAM and point cloud registration have developed rapidly. Unlike mobile scanning measurement systems based on GNSS, this type of equipment can easily obtains 3D point cloud data of targets in complex environments. This paper uses the Heron mobile backpack 3D laser scanning system which is based on IMU combined with the point cloud registration algorithm to conduct a 1:500 large-scale mapping production test, and then evaluates its accuracy and analyzes its efficiency. The results show that the accuracy and efficiency of the mobile backpack 3D laser scanning system in large-scale mapping are not inferior to traditional measuring methods, which demonstrates a vast development prospect of this equipment.

Remote sensing monitoring of water erosion desertification and spatio-temporal differentiation of its influencing factors in the Yunnan-Guizhou Plateau in recent 30 years

GAO Zhaozhong, HUANG Yajun, WEI Haixia, ZHANG Jinlan

2021, 0(10):  117-122.  doi:10.13474/j.cnki.11-2246.2021.317

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The Yunnan-Guizhou Plateau (YGP) is a typical seasonal arid ecological fragile area, and water erosion desertification (WED) that is caused by water flow has become one of the important ecological and environmental problems in the region. In this paper, long-term Landsat datasets are used to monitor the temporal and spatial variation trend of WED for the past 30 years in the YGP, and the spatial and temporal differentiation of its influencing factors is analyzed. A multi-index rule classification algorithm is proposed for remote sensing monitoring of WED in the YGP, and three key influencing factors (such as vegetation area, GDP and precipitation) are selected to analyze the spatio-temporal differentiation of the WED influencing factors using geographic weighted regression (GWR) model in the YGP. The experimental results are shown as following:① the main area of WED in YGP can be divided into Dian-Gui-Qian area, Sichuan-Yunnan border area, Dianxi area and Mengzi region. ② the WED expansion in the YGP can be divided into three stages as follows:a slow increase from 1989 to 2010, rapid expansion from 2010 to 2013, and a slight increase from 2013 to 2016. ③ The relationship between the three key infulencing factors and water-erosion desertification presents different spatial size in different numbers, positive and negative effects and the spatial distribution difference of factor combination effects. The local economic development and climate change exacerbate water-erosion desertification in local areas. The research results will provide theoretical basis and support for the fine prevention, control and treatment of water erosion and desertification in the YGP.

Environmental change monitoring in Qinghai province based on remote sensing image

HAN Jianping

2021, 0(10):  123-126,145.  doi:10.13474/j.cnki.11-2246.2021.318

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Based on the analysis of remote sensing images, this paper uses the optimized K-means algorithm to detect environmental changes in Qinghai province, make reasonable plans for the use of land based on the predicted results, finally to achieving sustainable development. This article compares the experimental results with the actual results of field operations and local policy planning. The results show that the algorithm in the article has an accuracy of more than 75% in predicting land changes and future trends, which verifies the feasibility of the algorithm, this ensures that land resources can be used reasonably while the economy is developing, and the environment can be effectively protected.

Analysis of combined prediction model of subway deformation based on wavelet denoising

YANG Chunyu, REN Xingda, JIANG Huinan, YUAN Yue, WANG Zilin

2021, 0(10):  127-131.  doi:10.13474/j.cnki.11-2246.2021.319

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By analyzing the subway monitoring data and establishing the corresponding prediction model, the possible deformation in the future can be prospectively predicted, so as to ensure the safe construction and operation of the subway. Taking the foundation pit project in Beijing as an example, the deformation monitoring scheme is introduced. Taking a monitoring point as an example, the wavelet analysis is used to de-noising the original monitoring data of a monitoring point. The time series analysis model and BP neural network model are respectively used to model and analyze the de-noised data, and the fitting value of the original data and the predicted value of the future deformation are obtained. The deformation results are obtained by using the coherent point timing InSAR Sentinel-1A satellite images at the same time. Finally, by analyzing the predicted value and the actual value of the two models, comparing with InSAR results, the advantages and disadvantages of the two models in the application of subway deformation monitoring data can be compared.

A video intelligent detection method for urban underground drainage pipe based on improved convolutional neural network

PENG Shugang, WANG Dacheng, TAN Junhui, AO Xuanfeng, YU Jiaying

2021, 0(10):  132-135,167.  doi:10.13474/j.cnki.11-2246.2021.320

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Urban underground drainage pipeline is an important infrastructure in municipal engineering, but with the aging of the pipeline, different types of defects begin to appear, it is an important challenge that how to identify the defects in a timely and effective manner for municipal management. In this regard, this paper proposes an IM-CNN algorithm based on improved convolutional neural network at the use of latest deep learning to recognize the pipeline video images intelligently. This algorithm uses the framework of InceptionV3. At the meantime, we design an improved feature fusion strategy and a new objective function for pipeline recognition for characteristics that defects in different categories of pipeline images has the unbalance of different categories. Experiments based on the underground drainage pipeline data set show that the predictive recognition ability of the proposed algorithm is not only superior to the traditional machine learning algorithm but also superior to the existing algorithms that directly utilize the convolutional neural network.

Application of EM2040C multibeam echosounder system in the quantitative monitoring of sea sand mining

REN Jianfu, WEI Zhongyang, ZHANG Zhilin, QUAN Junping, CHENG Shaoqiang

2021, 0(10):  136-140.  doi:10.13474/j.cnki.11-2246.2021.321

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Multibeam echosounder technology plays an important role in underwater topographic survey, and this technology has been used in ocean and inland water survey.This paper presents the basic components and performance of the EM2040C multibeam echosounder system and introduces its application in the monitoring of sea sand resources. The quantitative monitoring techniques and data processing progress has also been discussed. The research results show that the EM2040C multibeam echosounder system can quickly and efficiently obtain the sea floor terrain data. The results can meet the requirements of the relevant specifications and the EM2040C multibeam echosounder system can be widely applied in the quantitative monitoring of sea sand mining.

Intelligent identification system of drainage pipelines defects based on deep learning model

WANG Dacheng, TAN Junhui, PENG Shugang, ZHONG Zhensheng, CHEN Guoqiang, LI Guoqiao

2021, 0(10):  141-145.  doi:10.13474/j.cnki.11-2246.2021.322

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The health condition of the drainage pipeline directly affects the drainage effect of the whole city. In order to find the hidden danger of the drainage pipeline, it is necessary to detect the internal defects of the pipeline in time. CCTV detection technology is currently the most common pipeline defect method, but there are some problems such as low automation degree, low work efficiency and heavy reliance on manual experience. To solve these problems, this paper combines the deep learning technology with the detection technology of drainage pipeline, and put forward an intelligent identification technology of drainage pipelines defects based on deep learning model. Meanwhile, the intelligent identification of pipeline defects and pipeline detection workflow are closely combined to realize the rapid and automatic generation of drainage pipeline detection report, thus greatly improving the detection efficiency of drainage pipeline defects.

Cloud storage and heatmap generation method of trajectory big data

ZHANG Hao, ZHANG Jianqin, GUO Xiaogang, LU Jian, LU Hao

2021, 0(10):  146-149.  doi:10.13474/j.cnki.11-2246.2021.323

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At present, WebGIS-based heatmap display of large trajectory data has the problems of long mapping time-consuming and poor interaction between user's mobile scaling and zooming.This paper establishes a storage model of track data and map data based on HBase, which provides a storage basis for the thermal diagram display of large track data on electronic maps.A visualization method based on clustering is proposed for trajectory data heatmap, which can effectively reduce the amount of data drawing calculation and data transmission, and improve the efficiency of rendering and displaying heatmap.Experiments showed that this scheme can store trajectory data and electronic map data, improve the efficiency of visualization drawing of heatmap, and provide technical support for trajectory data mining and analysis.

Production benefits evaluation of cultivated land in counties based on spatial characteristics: take the Miao-Bouyei autonomous county of Ziyun as an example

LI Hui, WU Qiming, SHEN Chaoyong, LIU Fang, LI Ting, ZHANG Zheng

2021, 0(10):  150-153.  doi:10.13474/j.cnki.11-2246.2021.324

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This study takes the Miao-Bouyei autonomous county of Ziyun as a pilot site and uses geographic information spatial analysis technology to analyze and evaluate the impact of spatial factors- such as the characteristics of farmland, the distribution of agricultural material transportation facilities, and the distribution of agricultural irrigation resources, on the productivity of cultivated land. This study selects influential factors from the results of the census of geographical conditions and geochemical surveys, constructs a sample set of influential factors, proposes the concept of gradient distance, simulates the weight of economic benefits of graded farmland, and builds a partial least squares regression model to evaluate the impact of each factor on farmland production. Finally, from the perspective of geographic space, measures to improve county agricultural production are proposed.

Design of comprehensive experiment scheme of resource and environment remote sensing course for the cultivation of research ability of senior undergraduates

FAN Deqin, SUN Wenbin, ZHAO Xuesheng, YUAN Debao, CHEN Wei, LI Jun

2021, 0(10):  154-158.  doi:10.13474/j.cnki.11-2246.2021.325

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In recent years, with the improvement of the scale of graduate students, it is necessary to strengthen the cultivation of research ability for senior undergraduates in remote sensing teaching. Taking the course of remote sensing of resources and environment in mining area as an example, this paper puts forward a semi-open and expandable comprehensive experimental framework and shows the practical effect, so as to guide students to change from passive acceptance to active thinking, and lay a good foundation for students to enter the social work position or smoothly transfer to a higher learning stage.

A tunnel segment segmentation and section extraction based on point cloud model of cross-section datum plane

YU Jianwei, LIAO Jianghai, CHEN Zhipeng, XIONG Yonggang, XIONG Zhimin

2021, 0(10):  159-162.  doi:10.13474/j.cnki.11-2246.2021.326

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Accurate measurement of tunnel deformation is of great significance for understanding the changes and development rules of the tunnel lining structure, and ensuring the safe operation of the tunnel. In this paper, the laser point cloud of subway tunnel is obtained by rail-mounted mobile three-dimensional laser measurement system. Combined with the geometric characteristics of the cylindrical surface, a method for constructing a shield tunnel point cloud model based on the projection of a cross-section datum plane is proposed. The height gradient and three-dimensional features of the section datum plane point cloud are used to segment the tunnel ring and extract the tunnel section to obtain the continuous cross section of the shield tunnel, which provides a foundation for tunnel deformation monitoring.

Application of 3D laser scanner in actual measurement of electric power engineering

WEN Yuwei, DENG Changyong, ZENG Depei, WENG Xiangyang, QIU Rongfu

2021, 0(10):  163-167.  doi:10.13474/j.cnki.11-2246.2021.327

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In order to solve the problems of low efficiency and poor reliability of data accuracy obtained by manual aerial operations in some work of traditional power engineering, this paper proposes to apply three-dimensional laser measurement technology to the field of power engineering, by taking advantage of non-contact measurement, safety and high speed, high data accuracy and reliability of the three-dimensional laser scanner to reduce the errors caused by human factors in the measurement.The experimental results show that the error between the result of the electric tower height measurement, clearance height measurement and coordinate measurement measured by this technology and by the total station is within the range of allowable error.