Table of Content

25 August 2022, Volume 0 Issue 8

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Spatio-temporal changes of water conservation in Poyang Lake ecological economic zone from 2000 to 2019

CHEN Zhuan, LIU Ziqiang, WEI Xiaojian, LIU Mingzhao

2022, 0(8):  1-6.  doi:10.13474/j.cnki.11-2246.2022.0253

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Water conservation is an important aspect of ecological protection, which is of great significance to the ecological protection of the Poyang Lake ecological economic zone. Based on the water production module of the InVEST model, this paper analyzes the temporal and spatial changes of water production and water conservation in the Poyang Lake ecological economic zone from 2000 to 2019, and uses spatial autocorrelation to explore the spatial relationship between elevation and slope and water conservation functions. The results show that: ①The multi-year average water production depth of the Poyang Lake ecological economic zone is 971.04mm, and the multi-year average water conservation depth is 299.298mm. ②The water conservation depth of the study area increased first and then decreased, with a large change, showing an upward trend as a whole. ③The water conservation function is geographically distributed, and the important and extremely important areas are mainly distributed in the eastern and northwestern woodlands. The general important areas are distributed in the Poyang Lake plain. ④Water conservation is positively correlated with elevation and slope, and high values of water conservation mostly occur at high altitudes and steep slopes.

Long-term vegetation variation and its response to hydrological regime in Poyang Lake wetland based on GEE

ZHU Jiangtao, AI Jinquan, CHEN Xiaoyong, NIU Chunmei, XIAO Shaolong

2022, 0(8):  7-13.  doi:10.13474/j.cnki.11-2246.2022.0225

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In order to solve the scientific problem of long-term vegetation evolution in Poyang Lake, this paper extracts the annual vegetation distribution range of the rising water period, the high water period, the receding water period and the low water period from 2000 to 2017 based on the Google Earth Engine(GEE) remote sensing big data platform and CART classification regression tree algorithm, and expounds the spatio-time characteristics of the vegetation change. On this basis,It combines with water level data, the response relationship between wetland vegetation and hydrological regime is analyzed. The results show that: ①The average vegetation area of Poyang Lake wetland during the low water period, the rising water period, the high water period and the receding water period from 2000 to 2017 is 846.35km²、679.03km²、172.35km²、508.63km². ②From 2000 to 2017, the total vegetation area of Poyang Lake wetland increased at different water levels and tended to evolve towards the center of the lake. ③The vegetation area of Poyang Lake is significantly affected by water level, and the water level is negatively correlated with the vegetation area. The precipitation anomaly (such as extreme precipitation or severe drought) is the main factor leading to the significant deviation of the average vegetation area. The results of this study have scientific reference significance for the formulation of wetland protection and restoration policies in Poyang Lake.

Spatio-temporal evolution of eco-environment quality and the response to climate change and human activities in northern China

WANG Yubai, GENG Jia, ZHOU Yuyu, ZHOU Zeyu, FANG He, GENG Jing, ZHANG Rui, XU Dong

2022, 0(8):  14-21,35.  doi:10.13474/j.cnki.11-2246.2022.0226

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The northern China that is a typical climate change sensitive area in China has a vast territory, complex and diverse landforms, a wide distribution of arid areas, and also serious problems such as wind and sand hazards and soil erosion. However, the laws governing the evolution of eco-environmental quality (EEQ) and its response to climate change and human activities in northern China in recent decades are still unclear. Understanding these laws is of great significance to further strengthening the ecological civilization construction and maintaining biodiversity in northern China. Based on CHEQ and other remote sensing data such as climate indicators and nighttime light data, using trend analysis, coefficient of variation, partial correlation analysis, multiple regression analysis, re-standard range analysis, this study explores the characteristics of the temporal and spatial changes of the EEQ in northern China from 2001 to 2018 and its response to climate change and human activities. The results show that: ①The CHEQ index in northern China from 2001 to 2018 shows a slight downward trend, with a spatial distribution characteristic of “high in the east and low in the west, high in the north and south, and low in the middle in the north”; ②In the past 18 years, only 18.66% of the areas where the EEQ has been improved in northern China, while degraded areas accounted for more than 40% of the total area; ③The EEQ has a significant negative correlation with temperature and human activities (P<0.05), and a significant positive correlation with precipitation (P<0.05); ④The area where climate change plays a leading role in the change of EEQ has reached 90% of the study area. While making up for the deficiencies of existing research, this study can provide a scientific basis for quickly grasping the changing laws of the EEQ under the development of green economy in northern China and improving the effect of ecological civilization construction, and provide theoretical support for the scientific policy of “Lucid waters and lush mountains”.

Spatio-temporal changes of vegetation coverage in the Loess Plateau of northern Shaanxi and its attribution analysis

ZHANG Bo, LIU Changxing, WANG Xuan

2022, 0(8):  22-29.  doi:10.13474/j.cnki.11-2246.2022.0227

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With the Google Earth Engine (GEE) cloud platform, this study uses Landsat imagery, temperature precipitation and land use types data as the basis, and Theil-Sen Median trend analysis, Mann-Kendall test, partial correlation and multiple regression residual analysis to analyze the 1999—2018 the spatial and temporal characteristics of vegetation cover, change trends, and the effects of climate change and human activities on different land use types on the Loess Plateau in northern Shaanxi. The resufts are that: ①The interannual FVC of the Loess Plateau in northern Shaanxi shows an improving trend from 1999 to 2018, and its average growth rate is 0.0049/a (P<0.01), and the area with an increasing trend of vegetation cover accounted for 74.43% of the total area. ②the partial correlation coefficients of vegetation cover with precipitation and temperature has obvious spatial differences, and vegetation growth is more sensitive to changes in precipitation. ③Climate change and human activities together are the main causes of vegetation growth, where the effect of climate change on vegetation FVC ranges from -0.0010 to 0.0036/a, while the effect of human activities on vegetation FVC ranges from -0.0461 to 0.0490/a.④Among the different land use types, climate change increases the most for water bodies and the least for coniferous and broad-leaved forests; while human activity changes increase the most for human occupied land and the least for broad-leaved forests.

Spatio-temporal changes of ecological service values in Yunnan-Kweichow Plateau

ZHANG Xuepeng, ZHANG Fengjiao, CHEN Wei, LI Guangchao, BI Pengshuai, WANG Zhe

2022, 0(8):  30-35.  doi:10.13474/j.cnki.11-2246.2022.0228

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Aiming at the problem how to change the ecosystem service values (ESVs) in Yunnan-Kweichow Plateau after the ecological restoration project was carried out, based on equivalent factors and spatial autocorrelation analysis methods to study the spatio-temporal characteristics of ESVs in the Yunnan-Kweichow Plateau in this paper. The results show that: ①The conversion of land use types is mainly the conversion of cultivated land to construction and water. ②After the ecological restoration projects, the ecosystem has been improved, ESVs first decreased and then increased in 38 years, with a cumulative increase of 9.491 billion yuan. The ecological adjustment capacity of forests and the total value generated are more than 218 billion yuan, and the least is desert, which is about 10million yuan. ③The spatial distribution pattern of ESVs is higher in the southwest and lower in the middle. ④ESVs from 1980 to 2018 showed a significant positive spatial correlation, and the Moran index was greater than 0.46, showing obvious clustering characteristics.

High-resolution remote sensing image change detection network with Transformer structure

FENG Weiming, ZHANG Xinchang, SUN Ying, JIANG Ming, GAN Qiao, HOU Xingxing

2022, 0(8):  36-40,92.  doi:10.13474/j.cnki.11-2246.2022.0229

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In order to solve the problem of global context information capture in remote sensing image change detection, this paper proposes TSU-Net based on twin structure, jump link structure and Transformer structure. The model encoder adopts a hybrid CNN-Transformers structure to capture the global context information of remote sensing images with the help of self-attention mechanism, which enhances the model's ability of long distance context modeling for pixel-level remote sensing image change detection task. The model is tested in the LEVIR-CD dataset and the CDD dataset, and the F1 scores are 0.9073 and 0.9314, respectively, which are superior to the comparison models.

Improving the spatial resolution of GRACE satellites based on high-resolution hydrological simulations

LIU Hongliang, ZHANG Gangqiang, ZHANG Dasheng, YIN Wenjie, MENG Xiangbo

2022, 0(8):  41-47.  doi:10.13474/j.cnki.11-2246.2022.0230

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To overcome the limitation of the coarse spatial resolution of GRACE observations, this study selects PCR-GLOBWB simulations as the reference data with higher resolution. Three kinds of downscaling schemes are employed to improve the resolution of GRACE data in Hebei province from 0.50° to 0.05°, namely add weight downscaling method (AWDM), multiply weight downscaling method (MWDM), and error distribution downscaling method (EDDM), respectively. The results indicate that the AWDM-based scheme can not only preserve the original spatial characteristics of GRACE observations, but also give signals at local areas. Although the EDDM-based scheme can also provide ideal downscaled results, there are obvious jumps with regard to the signals between the junction of different pixels. In contrast, the worst performance is observed in the MWDM-based scheme, which is significantly different from the actual GRACE signals. In-situ groundwater level measurements highlight that the AWDM-based downscaling scheme is superior to other downscaling methods, and can provide reasonable downscaling performance with the correlation up to 0.81. This study provides an effective guarantee for obtaining high spatial resolution groundwater storage data in Hebei province.

Similarity method for high-resolution remote sensing scene change detection

HUANG Yuhong, ZHOU Weixun

2022, 0(8):  48-53.  doi:10.13474/j.cnki.11-2246.2022.0231

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To solve the problem that the process of traditional remote sensing image scene change detection is complex and severely depends on the classification performance, a scene change detection method considering both global and local scene similarity is proposed in this paper. Firstly, the two temporal remote sensing images are cropped into image patches with fixed size to construct scene pair database, and divided into training and testing dataset. Secondly, the two-branch convolutional neural network integrating scene global and local similarity is constructed to carry out similarity learning of scene pairs. Then, the trained network is used to extract the similarity of scene pairs of the training dataset, and the best similarity threshold is determined via traversal. Finally, the testing dataset is categorized into changed and unchanged scenes based on the similarity threshold to obtain the final change detection results. The experimental results show that the overall accuracy and Kappa of the proposed method is 0.94 and 0.88, respectively, which outperforms traditional detection after classification approach and is a simple yet effective change detection method.

The response of urban and rural ecological quality to the expansion of construction land in rapid economic growth zone: taking Hefei as an enample

WANG Jian, SU Tao, ZHU Fei, XIA Jun, LIAO Jinyi

2022, 0(8):  54-60.  doi:10.13474/j.cnki.11-2246.2022.0232

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Since the 21st century, China's economic growth has promoted the rapid development of urbanization, but also brings a series of environmental problems to a certain extent. Taking Hefei in Anhui province, one of the fast economic-developing in the Yangtze River Delta region, as a study area, based on Landsat images of 2002, 2010 and 2020, this paper discusses the response of urban and rural ecological changes to the expansion of construction land by using improved remote sensing ecological index and introducing urban expansion intensity and urban center of gravity center displacement model. The results show that: From 2002 to 2020, the ecological environment quality of the main urban area and surrounding towns of Hefei show a general deteriorating trend. The average MRSEI of surrounding towns decreases from 0.747 in 2002 to 0.495 in 2020, a decrease of 33.7%. The average MRSEI of the main urban area decreases from 0.669 in 2002 to 0.491 in 2020, a decrease of 28.73%. The decline in the ecological quality of surrounding towns is higher than that of the main urban area, the expansion of construction land is stronger than that of the main urban area, and the ecological damage is more serious. The deteriorating ecological environment is mainly distributed radially from the main urban area to the surrounding towns. The areas with improved ecological environment are mainly distributed around the old urban area. The areas of urban expansion and the deteriorating ecological environment shown by the MRSEI evaluation results basically coincide, and the ecological environment changes have a obviously negative correlation with the expansion intensity of urban construction land.

Improved hyperspectral unmixing initialization method and its applicability analysis

WEI Lei, DING Laizhong, WANG Wenjie, GAO Yantao, HUANG Pengfei, LI Chunyi, ZHANG Yongjie

2022, 0(8):  61-67.  doi:10.13474/j.cnki.11-2246.2022.0233

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There are a large number of mixed pixels in hyperspectral images, which greatly limit the quantitative application of hyperspectral images, and it is especially important to perform pixel unmixing efficiently and accurately. The initialization of the endmember matrix, the cost function of the algorithm itself and the iterative rules of the algorithm often result in different end-element spectra and end-batch abundances. Under different conditions, it is especially important to select appropriate initialization methods, cost functions and iterative rules to make the hyperspectral unmixing results better. In this paper, a new block initialization method based on Euclidean distance and spectral information divergence is improved. The improved block initialization method is superior to other initialization methods in the case of low to medium SNR. At the same time, a lot of experiments are carried out on the two aspects of initialization and algorithm itself. The results show that:①The block initialization is better than the global initialization.②The gradient iterative NMF algorithm is faster than the multiplicative iterative NMF algorithm, but easy to fall into local minimum.③Block multiplicative iterative NMF algorithm can obtain better endmember abundance information than standard multiplicative iterative NMF algorithm;④Block gradient iterative NMF algorithm is not applicable to the spectral unmixing process after random initialization.

Assessment of debris flow susceptibility based on different slope unit division methods and BP neural network

LI Kun, ZHAO Junsan, LIN Yilin, ZHOU Bao

2022, 0(8):  68-74.  doi:10.13474/j.cnki.11-2246.2022.0234

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Selecting appropriate assessment units is the key to the assessment of debris flow susceptibility. In order to explore the impact of different methods of slope unit division on the assessment results of debris flow susceptibility. Taking Dongchuan district as an example, this paper compares and analyzes the effects of two slope unit division methods: hydrological analysis method and curvature watershed method in the evaluation of debris flow susceptibility. Based on the interpretation of debris flow points, the slope units with different division methods are used as the assessment unit, and the preliminary selected index factors are analyzed for multicollinearity and contribution rate to improve the index factor system, and finally build the debris flow susceptibility evaluation model based on BP neural network. The results show that the very high and high susceptibility areas of debris flow are mainly distributed in the Xiaojiang river valley and the south bank of Jinsha river in the study area, where the geological environment is fragile and the risk is high; The AUC value of the susceptibility model based on the curvature watershed method is 0.8658, which is higher than that of the hydrological analysis method of 0.8153, indicating that the slope unit divided by the curvature watershed method is more suitable for debris flow susceptibility assessment in the study area.

A forest fire spread simulation method of coupling Rothermel model and particle system

YAO Yanxia, MIAO Shuangxi, HUANG Xu, ZHANG Bo

2022, 0(8):  75-80.  doi:10.13474/j.cnki.11-2246.2022.0235

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The scientific and accurate simulation of forest fire spreading process is of great significance for disaster prevention, mitigation and relief work.Existing simulation algorithms for forest fire spread has low coupling degree in calculation of fire spread and visualization expression method, and it is difficult to visually express the calculation results of dynamic physical model in real time.In response to this question, this paper comprehensively considers the advantages and disadvantages of various fire spread models, and selects Rothermel model which is the widely used as the physical model.The Huygens theory is used to optimize the boundary points in fire evolution range and the ignition density threshold is used to control the balance between the number of seed points.Using Boolean operation to improve the calculation efficiency of multiple ignition point spread range, the fire model is closely coupled with the particle system of Open Scene Graph to complete the visual expression of fire evolution.It realized the accurate calculation and real-time, realistic simulation of forest fire spread, and provides information support for disaster emergency departments.

A 3D modeling cluster approach based on compatible task assignment

WU Yange, GE Yingwei, XU Guozheng, GUO Bingxuan, PENG Zhe

2022, 0(8):  81-86.  doi:10.13474/j.cnki.11-2246.2022.0236

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In response to the existing clustering methods that have wasted CPU and GPU resources on nodes during 3D modeling of tilt images and the inefficiency of 3D modeling,this paper proposes a cluster 3D modeling method based on compatibility. Firstly,by dividing the 3D reconstruction task based on two-step submission,the execution efficiency of the cluster is improved while the modeling effect remains unchanged. Then,we propose the compatibility task node allocation method for the waste of cluster node resources,and complete the implementation of the 3D modeling cluster method based on the compatibility task allocation. Finally,the experimental test of large-scale image 3D reconstruction is conducted to verify the superiority of the compatibility theory on the optimization of the allocation method under the experimental environment of big data,which proves that the algorithm of this paper has significantly improved the efficiency of 3D modeling.

Spatial location method of dynamic targets in surveillance videos

HAN Shijing, MIAO Shufeng, HAO Xiangyang, CHEN Runze

2022, 0(8):  87-92.  doi:10.13474/j.cnki.11-2246.2022.0237

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Aiming at the problem of dynamic targets' location in surveillance videos, this paper studies the mapping relationship among surveillance cameras, target pixel coordinates and geographical scenes on the premise of considering the camera distortion, and proposes the spatial location methods based on the digital surface model (DSM) and the plane constraint. Firstly, the camera calibration is completed and the imaging model of the camera is determined. Secondly, the pixel coordinates of the targets after distortion correction are extracted, and the 3D geographic coordinates of the targets are calculated by the two spatial location methods. Finally, the positioning accuracy is evaluated, and the application characteristics of the two spatial location methods are analyzed. The methods proposed in this paper parse the target data located by pixel coordinates into the spatial geographic information located by 3D coordinates, which provides a unified geographic reference framework for multi-camera target tracking.

Automatic division and regularization of indoor 3D point cloud space

WANG Jingchun, TANG Shengjun, WANG Weixi, LI Xiaoming, LI You, XIE Linfu, ZHU Jiasong

2022, 0(8):  93-97,138.  doi:10.13474/j.cnki.11-2246.2022.0238

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Accurate spatial division is an important basis for realizing indoor semantic modeling and topology reconstruction.As a commonly used indoor space data carrier, 3D point cloud is of great significance to extract and normalize semantic information in indoor space based on 3D point cloud.This paper proposes an indoor scene segmentation based on the morphological segmentation method, and combines the vector regularization method.Firstly, spatial segmentation elements are extracted based on regional growth algorithm and linear fitting method, generate binary image through plane projection, and then use distance transformation and watershed algorithm to complete spatial segmentation. Secondly, linear fit of indoor spatial mesh.This paper verifies 4 sets of actual scene data, including 3 sets of ISPRS data sets and 1 set of actual scene collection data. The test results show that the indoor space segmentation and regularization method proposed in this paper can accurately and quickly complete the extraction of indoor space elements.

Review on aerial path planning of UAV for 3D reconstruction

WU Changsong, PENG Yeping, CAO Guangzhong, YAN Yan

2022, 0(8):  98-103,122.  doi:10.13474/j.cnki.11-2246.2022.0239

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In the 3D reconstruction of urban scene, using UAV to collect images at low altitude has become the mainstream scheme. The UAV captures images at low altitude based on the optimal aerial path can improve the accuracy and efficiency of 3D reconstruction. Therefore, many researchers have investigated and developed the UAV aerial path planning methods in recent years. Accordingly, many viewpoint planning and flight path planning approaches have been reported. To summarize the principles of these new methods, this paper describes the working process of aerial path planning techniques, and details the modeling methods of aerial path planning based on the reconstructed 2D and 3D models of environments, as well as the unknown environment. Then the advantages and disadvantages of different path planning methods are analyzed, and the development trends are also discussed. This review can provide an important reference for the development of UAV control, aerial photography technology, and 3D reconstruction of large-scale scenes.

Slope body factor fusion of grid DEM

ZHOU Fangbin, XIE Caichang, WANG Jun, CHEN Bailiao, HU Yi

2022, 0(8):  104-109.  doi:10.13474/j.cnki.11-2246.2022.0240

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Slope body is the basic unit of natural terrain entity. It is beneficial for regional landform analysis and planning to use comprehensive slope factor analysis and excavation of terrain implied information. Because of the current defect that the slope width factor has not been considered in the slope comprehensive expression factor(LS), a new slope fusion factor(LSW) is acquired by integrating the slope length (L), slope (S) and slope width (W) with the normalized geometric operation method. Using DEM by intercepting a local area of a small watershed in the Loess Plateau as a typical study area, four patterns L×S×W, L+S+W, LS×W and LS+W are adopted for the fusion experiment based on the extraction of L, S, W and LS. The experimental results show that the L+S+W fusion pattern has the lowest mean value 0.2344 in the LSW factor variance matrix, effectively balances the contribution of each single terrain factor in LSW to the fusion slope factor LSW, and the L+S+W fusion pattern is demonstrated to be optimal by information entropy calculation.

Analysis of the centrality and symmetry of the network structure of China's three urban agglomerations using Baidu population migration

YUE Hanqiu, QI Jianwei, CHEN Yanhui, CHEN Liang, CHEN Huaixin

2022, 0(8):  110-116.  doi:10.13474/j.cnki.11-2246.2022.0241

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Focusing on the analysis of the centrality and symmetry patterns of the nodes and links on urban network, this study proposes a method framework which includes three “S” dimensions.It is strength, symmetry, and structure, respectively. Further, the above framework is applied to the migration network of Beijing-Tianjin-Hebei (BTH), Yangtze River Delta (YRD), and Pearl River Delta (PRD) urban agglomerations, and the following findings can be obtained: ① The urban nodes and the migration of people in the three major urban agglomerations have obvious hierarchical and symmetrical structures, respectively. ② The BTH, YRD, and PRD respectively presents a core-periphery structure with a surrounding, “>” shape, and one core and two wings. ③ The BTH presents a typical single-center structure, while the YRD and the PRD present obvious multi-center structure. The above findings can be helped to make suggestions for the urban positioning and regional planning of the three urban agglomerations, which can promote the coordinated development and integration of those regions.

The method for estimating the scale of vector spatial data based on spatial granularity

ZHONG Qiyang, GUO Qingsheng, WANG Yong, LUO An

2022, 0(8):  117-122.  doi:10.13474/j.cnki.11-2246.2022.0242

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Volunteered geographic information has been widely used in recent years. The data from some sources may lacks scale description. Therefore, it is necessary to estimate the scale of vector spatial data. This paper proposes a method to estimate the scale by calculating and counting the spatial granularity of vector spatial data. The road elements are used as examples,and this paper selects a variety of spatial granularity indicators, including the shortest straight segment length of road spatial object with the single-category and the smallest bend area of the same spatial object. The function of estimating vector spatial data scale is fitted by a linear interpolation. The process of estimating scale based on spatial granularity is described in detail, and the data sets include 1∶250000 scale data, 1∶1000000 scale data and 1∶4000000 scale data in Beijing city. In addition, we also count the number of different spatial granularity units, and establish the relationships between the number of spatial granularity unit and the scale based on the radical law. Finally, experiments verify the feasibility and effectiveness of the proposed method in this paper, which is conducive to the fusion and application of multi-scale and multi-source data.

Research on the key technology of the unified quasi-geoid refinement in the Beibu Gulf Economic Zone

PAN Zhengqiang, ZHONG Changhai, ZUO Tianhui, LIN Zile, KONG Jian, TANG Changzeng

2022, 0(8):  123-127.  doi:10.13474/j.cnki.11-2246.2022.0243

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In view of the lack of a unified elevation datum of terrestrial and marine for the construction of ecological civilization,the utilization of marine resources and the disposal of marine emergency rescue events in the Guangxi Beibu Gulf Economic Zone,this paper used 2764 gravity data and 8 GNSS/leveling data in Guangxi Beibu Gulf to solve this problem. Firstly,the gravity quasi-geoid in the area covering Guangxi Beibu Gulf sea area and continental coastline extending inland of about 15000 square kilometers is precisely determined by the Helmert's second condensation method. Then taking the EIGEN6C4 earth gravity field model as the reference gravity field,the determined gravity quasi-geoid is compared with the 8 GNSS/leveling data with an accuracy of 2.2cm. Finally,through spherical cap harmonic analysis,the quasi-geoid accuracy of the 2'×2' grid is improved to 1.6cm,and the terrestrial elevation datum is transferred to the Guangxi Beibu Gulf sea area and its islands,so as to realize the unified regional elevation datum of terrestrial and marine.

Building height extraction method based on sub-meter remote sensing image and its verification

LIU Xiaozhong, FENG Cunjun, DENG Xiaoyuan, ZHAN Yuanzeng, YU Hui, WANG Xingkun

2022, 0(8):  128-132.  doi:10.13474/j.cnki.11-2246.2022.0244

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Building height is the basic reference data in modern urban monitoring, planning, management and economic activities. In order to realize the extraction of building height information, this paper presents a method for inversion of building height based on Boltzmann curve. First of all, through the spectral characteristics of the building image, the method of multi-scale segmentation and remote sensing index classification are used to obtain the interesting area of the building shadow, then we obtain the sub-pixel position of the shadow according to the Boltzmann curve function in order to get the shadow boundary by linear fitting. After that, a height inversion model based on the geometric relationship between the sun, satellites, buildings and their shadows is built. Finally, Ninghai county is selected as the experimental area, and the main satellite remote sensing data of GF-2, GJ-1, Beijing-2 and WorldView-2 which spatial resolution are better than 1m on orbit for accuracy verification. The experimental results show that the medium error in the calculated building height is better than 2.5meters, which can be used for urban satellite remote sensing monitoring.

Construction of investigation and monitoring system of coal mining subsidence area based on multi-source data in Shanxi province

DU Yuhe, YANG Wenfu

2022, 0(8):  133-138.  doi:10.13474/j.cnki.11-2246.2022.0245

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In order to help improve the supervision system of natural resources, fulfill the requirements of ecological civilization construction, and provide high-quality and efficient land use guarantee services, the investigation and monitoring of coal mining subsidence area is of great significance. Based on multi-source remote sensing data, combining traditional measurement technology and modern remote sensing technology, this paper constructs the investigation and monitoring system of coal mining subsidence area in Shanxi province. The results show that the distribution of coal mining subsidence area in Shanxi province is basically found out, and its total area is 6500km², which is highly overlapped with the distribution of mining area and mined-out area in Shanxi province; and the land use is mainly forest land, cultivated land and grassland; and most of the land damage is light or moderate. 1221 villages which are affected by coal mining subsidence will be relocated, but more than 400 villages are not relocated.

Earthwork calculation and accuracy evaluation of UAV oblique photogrammetry

WANG Cheng, SHI Yujun, QUAN Fei, LI Qingxun, LI Jiahao, ZHOU Lü

2022, 0(8):  139-142,159.  doi:10.13474/j.cnki.11-2246.2022.0246

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In this article, Guangxi Xing’an survey area is taken as the study area, and 1031 tilt images and 3361 ground discrete points were obtained with unmanned aerial vehicle(UAV) and GNSS-RTK respectively. The ContextCapture software is used to construct the 3D model of the survey area. The elevation points of the 3D model of the survey area and the measured discrete points of GNSS-RTK are extracted by EPS to calculate the DTM earthwork volume. Assuming that the calculated results of the measured discrete points are the true values, the results show that the difference between the measured results and the true values of the UAV earthwork volume is 1050.9m³, and the error percentage is 0.9%. UAV oblique photogrammetry technology can quickly, low cost, high quality to complete the measurement of earthwork and provide accurate results and scientific data support for engineering projects.

Optimizing allocation of public service facilities in future community living circle based on time and space

YU Zheng, SHANGGUAN Zongshan, ZHOU Dandan, LIU Tongwei, HUANG Aojie, CHEN Xijia, XIE Wenyu, ZOU Chengchang

2022, 0(8):  143-148,154.  doi:10.13474/j.cnki.11-2246.2022.0247

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As the core content of community life circle, public service facilities directly determine the level of life quality of community life circle. How to quantitatively evaluate the construction of community public service facilities and provide scientific decision support for the future planning of facility construction has gradually become a major problem for planners and decision-makers. In this study,POI data is processed, counted and visualized by ArcGIS tool. On the basis of summarizing the quantitative evaluation methods of other people's community living circles, a set of evaluation model of public service facilities in community living circles is built by combining the local characteristics of Wenzhou. The model can be used to comprehensively score and grade various communities, and the future optimization direction of public service facilities can be mined according to the model scoring results. In addition, this study realizes the dynamic calculation and display of community living circle score, and provides decision support for the site selection of community service facility construction, road network construction and priority assessment of public service facility construction. This study can not only help planners and decision makers to quickly establish a quantitative understanding of the current situation of the entire regional living circle construction, but also help to optimize the allocation of public service facilities, and explore new ideas and methods for the evaluation and improvement of public service quality in community living circle.

Dense matching combining Mahalanobis distance and gradient descriptor

CHEN He, GUO Zengzhang, LIU Xuan

2022, 0(8):  149-154.  doi:10.13474/j.cnki.11-2246.2022.0248

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Aiming at the problems that sparse matching points can not meet the needs of 3D reconstruction and the traditional dense matching algorithm is unable to match the light dark transform image, this paper proposes a dense matching scheme combining Mahalanobis distance and gradient descriptor. The scheme uses the initial reliable homonymous points to establish a homonymous triangle network, and uses the corresponding midpoint of each triangle as the encryption matching primitive, take descriptor and Mahalanobis distance as two influencing factors to set up score calculation formula, take the person who exceeds the threshold as the matching point, traverse all triangles, update the triangulation network, and repeat the above steps until no new matching point is generated. With the help of network public data set, the experimental results show that the dense matching scheme proposed in this paper can better solve the problem of poor adaptability of traditional algorithms to light and dark transform images, and has good adaptability and stability to a variety of transform images.

Real scene 3D multi-source data scene fusion

ZHANG Guangwei, WU Hao, GUO Zhendong

2022, 0(8):  155-159.  doi:10.13474/j.cnki.11-2246.2022.0249

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In the urban real scene 3D construction, scene fusion of multi-source and multi-scale real scene 3D data can further improve the detail expression of real scene 3D, improve the integrity of urban real scene 3D, and meet the requirements of local update mechanism of real scene 3D. This paper has carried out relevant research on massive, heterogeneous and multi-scale real scene 3D fusion technology and methods, explored and improved the spatial accuracy matching and data edge connection methods of multi-source real scene 3D data, combined with the standardized and lightweight processing methods of real scene 3D data results, improved the scheduling and display efficiency of real scene 3D scenes, and further expanded the application field of real scene 3D fusion results.

Application of ArcPy scripting tool in quality control of new fundamental surveying and mapping

WU Houqing, XIONG Weikang, NIE Chenhui, WANG Ling

2022, 0(8):  160-164.  doi:10.13474/j.cnki.11-2246.2022.0250

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In the construction of new fundamental surveying and mapping system, data quality control is the key link. In this paper, taking the construction of new fundamental surveying and mapping in Zhejiang province as an example, we propose to write a Python scripting tool for geographic information data quality inspection based on ArcPy to realize automatic checking of graphics, attributes, topology, logical consistency, etc. and improve the quality and efficiency of data quality inspection. In the practice of quality control of new fundamental surveying and mapping production in Zhejiang province, the reliability and practicality of ArcPy scripting tool is verified through comprehensive comparison with FME and ArcGIS Engine quality inspection programs.

Application of 3D laser scanning technology in historic building facade surveying and mapping

KONG Linghui, LU Dezhong, YE Fei

2022, 0(8):  165-168,172.  doi:10.13474/j.cnki.11-2246.2022.0251

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With the advancement and renewal of modern scientific and technological means, the new technology principle of 3D laser scanning real scene reproduction is used to replace the technical means of traditional single-point facade surveying and mapping of historical buildings to maximize labor cost savings, improve work efficiency, and integrate details, precision and efficiency. Uniformly achieves maximum production capacity and provides more advanced and comprehensive original data archiving and final result delivery for historical building digital technology standards.

Application of Trimble SX10 3D laser scanner in hydrologic and sediment monitoring

SUN Zhenyong, FAN Xiaotao, YE Fei, CHEN Xugang

2022, 0(8):  169-172.  doi:10.13474/j.cnki.11-2246.2022.0252

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Based on the application requirement of hydrological and sediment monitoring, Trimble SX10 image scanner is used for topographic survey, which is compared with traditional observation methods. Massive point cloud data are obtained through 3D laser scanning technology, and section data are extracted for quality monitoring. The project implementation and result analysis show that the 3D laser scanning technology can meet the requirements of hydrological and sediment monitoring, effectively reduce the operation risk in mountainous areas, and improve the work efficiency. The technical scheme is feasible.