Table of Content

25 November 2019, Volume 0 Issue 11

Previous Issue    Next Issue

Research status and prospects of GB-SAR deformation monitoring technology

LIU Longlong, ZHANG Jixian, ZHAO Zheng, KANG Qi, XI Xiaofei

2019, 0(11):  1-7.  doi:10.13474/j.cnki.11-2246.2019.0341

Asbtract ( )   HTML ( )   PDF (1196KB) ( )  

References | Related Articles | Metrics

Ground-based synthetic aperture radar (GB-SAR) is a ground-based active microwave remote sensing technology developed in recent ten years. GB-SAR system can be used for non-contact, high precision, large-scale and long-distance deformation monitoring, which is of great significance in the field of deformation monitoring. Firstly, this paper introduces the basic theory and research status of GB-SAR. The main GB-SAR systems are summarized and the key parameters of the existing systems are listed in detail. Then we analyze the advantages and disadvantages of GB-SAR technology in the field of deformation monitoring such as infrastructure, landslides, mines, glacier movements and cultural relics protection and summarize the challenges faced by ground-based radar systems in practical applications. Finally, the application prospects are prospected from the aspects of deformation monitoring multi-dimension deformation and atmospheric correction.

Review and prospect of land cover mapping by remote sensing

ZHU Shuang, ZHANG Jinshui, LI Changqing, ZHENG Kuo

2019, 0(11):  8-11,43.  doi:10.13474/j.cnki.11-2246.2019.0342

Asbtract ( )   HTML ( )   PDF (1209KB) ( )  

References | Related Articles | Metrics

The study of land use/cover classification at regional scale is one of the important fields in the study of land use/cover change in the world. Accurate and timely acquisition of the characteristics of the earth's surface is essential to grasp the relationship and interaction between human and natural phenomena. Based on the characteristics of land cover remote sensing classification methods, this paper summarizes the research results here and abroad from hard classification methods, soft classification methods and the latest soft and hard classification methods, and analyses the classification strategies, characteristics and applicability of various methods. The results show that the soft and hard classification method can be flexibly applied to the characteristics of remote sensing images, such as the coexistence of pure and mixed pixels, and can effectively solve the spectral heterogeneity. It has broad application potential in remote sensing monitoring of land cover. In this paper, a framework of soft and hard classification land cover mapping method based on variable endpoints is proposed, and the research emphasis in the future is pointed out.

Accessibility of urban subway stations based on topological network modeling

HONG Wuyang

2019, 0(11):  12-16,25.  doi:10.13474/j.cnki.11-2246.2019.0343

Asbtract ( )  

References | Related Articles | Metrics

The traffic accessibility can be observed by studying the spatial connection of traffic network and the degree of connectivity between network nodes. In this paper, the three-dimensional topological network composed of underground rail transit and road traffic is modeled. The accessibility model is established based on railway stations using space syntax morphology analysis variables. Then, this paper analyzes the accessibility level and spatial characteristics of railway stations, and discusses the relationship between the station accessibility and the surrounding land use. The results show that the average accessibility of the railway stations in Shenzhen is 0.088 4, with a low dispersion degree. There have developed four high-value hotspots, namely Futian Central District, North Huaqiang Business District, Dongmen Business District and Houhai District. The business and office land have the highest correlation with the accessibility of the stations, while the industrial land is less affected by the stations. So the railway stations tend to locate at spatial nodes like business districts or office areas where the traffic is more concentrated. The railway stations can basically meet the development requirements of the surrounding land. 27 stations of the "high-medium" type or the "medium-low" type need to improve the functions of the integrated traffic system. This paper evaluates the accessibility of subway stations in Shenzhen and its relationship with the usage of land based on the coupling of the topological network. It proposes a research perspective of transformation from traffic lines to traffic stations, providing a reference for similar studies.

Research on escape path planning algorithm for high-rise buildings based on A*

JIN Hailiang, WANG Yingle, YUAN Ming, CHEN Menglong

2019, 0(11):  17-21,25.  doi:10.13474/j.cnki.11-2246.2019.0344

Asbtract ( )  

References | Related Articles | Metrics

In view of the complex internal structure of high-rise buildings and the problem of congestion in escape passages without evacuation guidance in case of fire, based on the improvement of A* algorithm, this paper proposes an escape path planning algorithm for high-rise buildings. The algorithm takes the node of internal road network of high-rise buildings as the key element, and integrates the location of fire, the density of personnel, the number of personnel and other factors to escape for life. The three aspects of point optimization, node expansion optimization and weight optimization are improved to realize the escape path planning in a high-rise building when fire occurs. Taking a high-rise building as an example, the feasibility of the escape path planning algorithm in a high-rise building is verified.

Application of path optimization algorithm in takeout distribution

CAI Lin, LI Yingbing, ZOU Zixin

2019, 0(11):  22-25.  doi:10.13474/j.cnki.11-2246.2019.0345

Asbtract ( )  

References | Related Articles | Metrics

In the logistics industry, especially in thetakeout distributionindustry, the distributors require the route of restaurants and customers to be as short as possible, and the order of access between the destinations is limited. The paper proposes a path optimization algorithm to solve the problem.The algorithm first generates an initial path based on the nearest neighbor algorithm, and then uses the LK algorithm to optimize. Finally, based on the characteristics of the problem, the terminal-2-opt method is used for secondary optimization.The experimental results show that the algorithm can effectively shorten the initial path length and provide a better feasible solution, which can effectively improve the efficiency of the distributors and has certain practical value.

Fast three-dimensional path planning method for UAV considering complex environment constraints

TANG Jun

2019, 0(11):  26-30.  doi:10.13474/j.cnki.11-2246.2019.0346

Asbtract ( )  

References | Related Articles | Metrics

Aiming at the inefficiency and inaccuracy of UAV's three-dimensional path planning in complex environments such as terrain, no-fly zone, meteorology, dangerous object and visual constraints, the paper proposes a fast three-dimensional path planning method for UAV considering complex environmental constraints by designing a multi-layer extended A* algorithm. This method analyses the typical complex environments on the UAV path, and constructs a three-dimensional path planning environment model. By combining with the UAV's own performance constraints, a multi-layer extended A* algorithm is designed for three-dimensional hierarchical expansion to search for the optimal reference path of UAV. Line simplification and line smoothing are used to simplify and optimize the reference path. Finally, the typical case area is selected to carry out the experimental analysis, which proves that the proposed method can quickly and accurately plan the optimal feasible path in complex environment.

Correlation analysis of ionospheric profiles for different GPS occultation missions

ZHOU Rong, HOU Weizhen, ZENG Chenxi, ZHANG Shaocheng, CHAI Bingyang

2019, 0(11):  31-38,73.  doi:10.13474/j.cnki.11-2246.2019.0347

Asbtract ( )  

References | Related Articles | Metrics

The occultation ionospheric electron density profile events obtained by low-orbit satellites COSMIC、GRACE、CHAMP and FY3C are defined as an occultation pair in a certain range to analyze the different types of occultation ionospheric products. The results show that:the silhouette of the electron density profile between COSMIC occultation consistent well,there are big deviation under 250 km and 500 km above,the deviation is small between 250~500 km,the correlation coefficient of NmF2 and hmF2 can reach 0.99 and 0.97,there are no obvious bias between different COSMIC satellites. The electron density profile have different differences between LEO satellite. By calculating electron density parameters(NmF2 and hmF2), the correlation coefficient of NmF2 and hmF2 between the COSMIC and CHAMP are 0.95 and 0.86 respectively, the correlation coefficient between COSMIC and GRACE are 0.98 and 0.94,the correlation coefficient between COSMIC and FY3C are 0.96 and 0.92. The electron density parameters of different occultation types also have high correlation which could validate the consistence of the GPS radio occultation profiles from different LEO satellite missions.

Quality assessment and accuracy optimization of DSM using GLAS laser altimetry data

HU Liuru, TANG Xinming, LI Guoyuan, FU Dongxia, DOU Xianhui, ZHAO Shihu

2019, 0(11):  39-43.  doi:10.13474/j.cnki.11-2246.2019.0348

Asbtract ( )  

References | Related Articles | Metrics

In this paper, a new method using satellite laser altimetry data directly is proposed to optimize and improve digital surface model (DSM) product accuracy. The experiment is implemented in central Asia, and DSM is produced by ZY-3 satellite. The elevation control points are selected from laser altimetry data based on multi-criteria constraint. Then DSM is corrected by the elevation control points using skewness, median, linear polynomial, quadratic polynomial model. The four models can effectively eliminate DSM systematic errors. In addition, the quadratic polynomial model is more applicable to flat and hilly land, and the linear polynomial is more applicable to alpine region. Preliminary test results show that the technical process of DSM accuracy optimization based on satellite laser altimetry data is feasible and the elevation accuracy of DSM is favorable after correction by the four models.

Multi-sensor fusion for navigation technology and trajectory prediction under urban roads

LI Tong, ZHANG Huibing, LIU Dingke, DAI Yujun, WU Dongqiang

2019, 0(11):  44-50.  doi:10.13474/j.cnki.11-2246.2019.0349

Asbtract ( )   HTML ( )   PDF (2169KB) ( )  

References | Related Articles | Metrics

Easy access to accurate and reliable trajectory data is the key to the intelligent development of transportation, tourism and other industries. In view of this, a multi-source vehicle integrated navigation system integrating GPS, SINS and OBD is designed to collect trajectory data. The FGP data fusion method is proposed to compensate the accumulated position error caused by sensor noise, and to predict the track position information when the GPS outage. To effectively avoid error accumulation, the INS error compensation model is established through combination of Gradient Boosting and Decision Tree, and the regression parameters of the model are optimized by Particle Swarm Optimization in this method. The GPS, SINS and OBD data fusion is realized by exploiting federal filter thereby improving the accuracy of trajectory information. The actual road test proves that the GSO device based on the FGP can collect continuous and accurate trajectory data under various road conditions.

A method for indoor location of mobile terminal based on target detection and PnP

LIU Zhenyao, LI Ruidong, PAN Jundao

2019, 0(11):  51-55.  doi:10.13474/j.cnki.11-2246.2019.0350

Asbtract ( )  

References | Related Articles | Metrics

Aiming at the problem that traditional visual positioning is susceptible to noise interference, the accuracy of target detection is low and the accurate pose information cannot be obtained, this paper proposes an indoor positioning method of mobile terminal based on convolution neural network for target detection and PnP. The target detection is carried out by Mask-RCNN, and the accurate pose information of camera is obtained by EPnP algorithm. The method is implemented systematically and experimented in real scenes. The experimental results show that the target detection accuracy is more than 98%, the single-axis positioning error is less than 0.35 m, which meets the accuracy of indoor positioning of mobile terminals, and has the advantages of high precision and good stability. It provides a new idea for indoor positioning of mobile terminal based on vision.

A single-epoch ambiguity resolution method using iterative weighted AFM

GAO Di, HE Wentao, LIN Xiaolong

2019, 0(11):  56-59,125.  doi:10.13474/j.cnki.11-2246.2019.0351

Asbtract ( )  

References | Related Articles | Metrics

In order to improve the success rate of attitude determination with global navigation satellite system (GNSS) in complex environments, the iterative weighted ambiguity function method (IWAFM) is proposed, which combines the idea of iterative weighted with the ambiguity function method (AFM). By designing a new fitness function which using the residuals to calculate the weights, the weights of different satellites can be automatically adjusted. The information of inertial sensors is used to shrink the search space of IWAFM, so that the amount of calculation is reduced. The experimental results show that IWAFM can effectively improve the fix rate of ambiguity in the complex environments compared with the AFM and CLAMBDA algorithms.

GNSS accurate positioning-point and setting-out of hoisting operation for construction tower crane

ZHOU Mingduan, LUO Dean, DING Keliang, ZHOU Lejie, WANG Jian

2019, 0(11):  60-63.  doi:10.13474/j.cnki.11-2246.2019.0352

Asbtract ( )  

References | Related Articles | Metrics

GNSS is one of important sensors for accurate-control of tower crane. The low-accuracy of m-level positioning based on pseudo-range is not meeting the development requirements of intelligent tower crane. In order to improve the positioning accuracy of tower crane via GNSS techniques, a precise positioning method applied to positioning-point and setting-out based on GNSS carrier phase observation is proposed in this paper. It is applied to intelligent command for construction tower crane, and a set of GNSS-based positioning-point and setting-out system of hoisting operation (short as GNSS_PLS) is designed and developed. The preliminary experimental results show that the accuracy of intelligent command of GNSS_PLS system is in cm-level, which verifies the effectiveness of the algorithm.

Control method of stable platform for aerial photogrammetry system of low altitude unmanned airship

YANG Ying, LIU Fengzhu, ZHAI Xi

2019, 0(11):  64-68,108.  doi:10.13474/j.cnki.11-2246.2019.0353

Asbtract ( )  

References | Related Articles | Metrics

In this paper, a three-axis stabilized platform control method based on small and light-sized low-precision GNSS/IMU system and PID algorithm is proposed to solve the attitude stabilization problem of low altitude unmanned airship aerial remote sensing system. The system combines dual GPS light and small combination GNSS/IMU system, adopts separate camera and GNSS/IMU system control mode, adopts PID control method, uses STM32 control chip circuit to realize stable platform control. The stability of the system is verified by flight test, and the experimental results also show that the method can effectively isolate the influence of the instability of the unmanned airship attitude on the imaging system and effectively improve the imaging quality, which is of great significance for improving the accuracy of the unmanned airship aerial survey system.

Remote sensing image building extraction based on deep learning and graph cut

LIU Ge, DENG Xingsheng

2019, 0(11):  69-73.  doi:10.13474/j.cnki.11-2246.2019.0354

Asbtract ( )  

References | Related Articles | Metrics

A method for automatically extracting buildings on high-resolution images based on convolutional neural networks and graph cuts is proposed. Firstly, the location of the contour of the building is located and detected by the convolutional neural network, and the outlines of the individual buildings are extracted one by one. The Gaussian mixture model (GMM) of the building and the non-building is respectively established by the detection result, and the minimum flow is minimized. The cut image segmentation method achieves global optimization, completes the preliminary extraction of the building, and finally optimizes with morphology. The feasibility of the method is proved by experiments.

Nanjing City urban change detection using the color-space transformation of COSMO-SkyMed intensity RC composition imagery

ZHANG Tao, WANG Yuan, CHEN Fulong, ZHOU Wei, HU Qi

2019, 0(11):  74-78,84.  doi:10.13474/j.cnki.11-2246.2019.0355

Asbtract ( )  

References | Related Articles | Metrics

The developed change detection method, by utilizing the non-local filtered SAR intensity RC composition, is sensitive in the extraction of small patches and linear features. Consequently, it will indicate a better performance in practical applications, in particular this method is not constrained by additional requirements, e.g. the spatiotemporal baseline. In this study, taking the intensity RC composite imagery as the data-source, a semi-automatic change detection method is proposed by utilizing color-transformed features. In order to realize the thematic updating of urban-area land, the corresponding data procedures include four primary steps, they are color space transformation, training-sample selection, supervised classification based image segmentation, and change region extraction. Taking Hexi New Town and Jiangbei Developing District (Nanjing) as example, the checking probability is better than 88% with the optimum parameter setting (3 features along with 10 training-sample categories).

Random forest-based land-use classification using multispectral LiDAR data

CAO Shuang, PAN Suoyan, GUAN Haiyan

2019, 0(11):  79-84.  doi:10.13474/j.cnki.11-2246.2019.0356

Asbtract ( )  

References | Related Articles | Metrics

Airborne LiDAR systems can quickly obtain three-dimensional coordinates of ground objects, which has been widely used in topographic mapping, engineering construction, environmental monitoring, and land-cover and land-use classification, and so on. This paper, by means of random forest algorithm, performs land-cover classification using airborne multispectral LiDAR data. The proposed method extracts features from elevation and multispectral images combined by three individual intensity images, performs a backward feature selection according to the variables importance calculated by RF, and finally applies RF to the multispectral images. All experiments are conducted on the Optech Titan multispectral LiDAR data.The experimental results show that RF can achieve a good performance in land-cover classification, and the proposed RF-based backward feature selection method contributes to the improvement of classification by iteratively removing redundancy and related features.

Identification of layover and shadows regions in SAR images: —taking Badong as an example

ZHANG Tongtong, YANG Honglei, LI Dongming, LI Yongjie, LIU Junnan

2019, 0(11):  85-88.  doi:10.13474/j.cnki.11-2246.2019.0357

Asbtract ( )  

References | Related Articles | Metrics

The identification of overlapping and shadow areas in SAR images is the primary work in landslide monitoring. In this paper, the geometric model of radar satellite imaging and the morphological method in image processing are used to comprehensively identify the overlap and shadow regions. Take the ALOS-2 data as an example. The reliability of the experimental method is verified by comparing the radar intensity images in this area.

Application of DBSCAN clustering and improved bilateral filtering algorithm in point cloud denoising

QU Jinbo, WANG Yan, ZHAO Qi

2019, 0(11):  89-92.  doi:10.13474/j.cnki.11-2246.2019.0358

Asbtract ( )  

References | Related Articles | Metrics

The density-based DBSCAN clustering algorithm is used to denoise the point cloud data, and the smoothing effect is achieved by the improved bilateral filtering method that conducts smooth treatment. Finally not only the noise points are effectively removed, but also characteristics of the point cloud model are retained. This article uses the representative building of Shenyang during the Republic of China-Shenyang Financial Museum as the experimental model. The experimental results show that the point cloud data obtained by the DBSCAN clustering algorithm and the improved bilateral filtering process are far more accurate than the original point cloud data, and the data is more accurate and denoising, point cloud denoising is better.

Study on the temporal and spatial variations of urban heat island of typical karst cities

CHEN Xuanchi, CHEN Rong, LIAO Yao, WU Yufeng, WANG Yueyue

2019, 0(11):  93-97.  doi:10.13474/j.cnki.11-2246.2019.0359

Asbtract ( )   HTML ( )   PDF (4714KB) ( )  

References | Related Articles | Metrics

The landsat images of 1989, 2003 and 2018 are used to invert the surface temperature of Xixiu District of Anshun City. Then, the study area's spatio-temporal variations and their causes of heat island development in the past 30 years are analyzed. In addition, the image-based inversion algorithm and the classification regression tree algorithm are combined to invert the surface temperature. After that, the accuracy of the inversion results are made through the weather station data. And a buffer is established for quantitative analysis such as correlation analysis in the study area. From the above researches, the results show that:First, the study area is affected by karst landforms, besides the main urban area, there are also a large number of high temperature areas in the suburbs. Second, in the past 30 years, the thermal effect of the study area has a significant correlation with the impervious surface and the area of green space. Finally, from 1989 to 2003, the urban heat island area of the study area gradually increased with urban expansion, but in 2018, the urban heat island phenomenon in the main urban area almost disappeared. After excluding the influence of meteorological factors and urban morphological factors, it is found that this is closely related to the vigorous urban greening in Anshun.

Monitoring urban land subsidence by dual-polarization Sentinel-1 data: a case study of Shanghai

XIONG Jiacheng, NIE Yunju, LUO Yue, LI Yongfei

2019, 0(11):  98-102,129.  doi:10.13474/j.cnki.11-2246.2019.0360

Asbtract ( )  

References | Related Articles | Metrics

Polarization is a very important concept in remote sensing satellite imaging.Different polarization data contain different ground information and have different application values.In view of the application of VV and VH polarization data in urban ground subsidence monitoring, the dual-polarization Sentinel-1 data is used to monitor the ground subsidence in the urban area of Shanghai. The reasons for the differences between the two monitoring results are analyzed and compared with the leveling monitoring data for verification. The results show that the monitoring integrity of VV polarization data is better than that of VH polarization data. The quality of coherence and the number of effective pixels of VV polarization data are both higher than that of VH polarization data.The deviation between monitoring results and leveling data is smaller than that of VH polarization data.

Convolutional-neural-network-based sewer defect detection in videos captured by CCTV

Lü Bing, LIU Yuxian, YE Shaoze, YAN Zhen

2019, 0(11):  103-108.  doi:10.13474/j.cnki.11-2246.2019.0361

Asbtract ( )  

References | Related Articles | Metrics

Sewer network is related to the public safety and environmental protection. The defect detection of sewer has received more attention. CCTV is a technology widely used in the sewer defect detection. Motivated by the success of the CNN (Convolutional Neural Network) in the image recognition, this paper proposes a CNN-based sewer defect detection to improve the intelligence and automation of the CCTV technology. Experimental results show that the proposed method is effective and the accuracy, recall and run-time meet the requirements of the sewer defect detection. Moreover, this method has been widely used in the city of Shenzhen.

Application of slope entropy of points in terrain simplification

LI Mingfeng, LI Lianyang, ZHAO Xiangyu, LU Haifang

2019, 0(11):  109-113.  doi:10.13474/j.cnki.11-2246.2019.0362

Asbtract ( )  

References | Related Articles | Metrics

Slope is an important factor to describe the landforms quantitatively. In view of the problem of few research on the slope in DEM terrain simplification, the concept and model of slope entropy of points, which can describe the terrain information, are proposed based on the information entropy. And what's more, a new method of terrain simplification is studied. Relied on the data in experimental areas, we compare the new method named SEP with the common method named VIP. It turns out that SEP can retain the terrain skeleton information effectively. In addition, SEP has a better result than VIP in retaining the primary terrain skeleton and abandoning the less important terrain skeleton. The new method has certain reference value for the following study on terrain simplification.

Discussion of digital map design based on famous paintings

LI Ruyan, JIAO Jizong, XIE Yaowen, DUAN Hanming, WEI Baocheng

2019, 0(11):  114-120.  doi:10.13474/j.cnki.11-2246.2019.0363

Asbtract ( )   HTML ( )   PDF (6699KB) ( )  

References | Related Articles | Metrics

The art of painting has the ability to evoke ideas based on emotional experience. The famous paintings, as a work of art, are characterized by rich tints, high contrast and harmonious color hues. In this study, we briefly introduce the basic principles of chromatology and put forward a map color design method based on famous paintings. Combined with traditional cartographic rules, map design and comparative analysis are carried out from the perspectives of composition and color by extracting palette and analyzing color pattern of the famous painting. The results show that the map design scheme can well exhibit the color and emotion of the painting when user chose the painting with similar visual structure of the cartographic region. Furthermore, referring the color pattern of famous painting to achieve the association between map elements and real features, it can well display the characteristics of landscape color and the cultural spirit of the cartographic region on the map. Therefore, the proposed method has a reference value for guiding map color scheme design and "user-centered" map design.

Research and application of precise trigonometric leveling to replace second-class leveling achieving river-crossing leveling

ZHANG Heng, HU Bo, YUAN Changzheng

2019, 0(11):  121-125.  doi:10.13474/j.cnki.11-2246.2019.0364

Asbtract ( )  

References | Related Articles | Metrics

This paper analyses the theory and method, error source, and precision indexes of Precise Trigonometric Leveling. It discusses the key problems of using Precise Trigonometric Leveling instead of Second-Class Leveling in River-Crossing Leveling, and furnishes operating methods and requirements which employ two High-Precision automatic collimating total stations to carry out River-Crossing Leveling in opposite observational directions. Applications of the method in the construction of Chongqing Rail Transit Loop Line were conducted, proving that the Precision Trigonometric Leveling can meet the accuracy requirements of Second-Class Leveling under certain conditions, and it also brings high economic benefits.

The adaptive combination adjustment of GNSS and leveling data

DING Alu, TIAN Jie, NIE Jianliang, LIU Xiaoyun, GUO Xinwei, ZHAO Dajiang, ZHANG Haiping

2019, 0(11):  126-129.  doi:10.13474/j.cnki.11-2246.2019.0365

Asbtract ( )  

References | Related Articles | Metrics

The combination adjustment is used to adaptively fuse GNSS and leveling by using the leveling height difference value and GNSS vertical velocity as observations. The constrained GNSS leveling points with the consistent movement trend between geodetic height and normal height are uniformly chosen to match the vertical movement. The scale of weight matrix between GNSS and leveling is adaptively computed and adjusted with the variance component estimation. The relative equivalent weight function is adopted to control the influence of the outlier and to improve the accuracy of combination adjustment. The GNSS and second-order leveling data in Shandong province is applied to test the new algorithm. It is shown that the algorithm can not only fuse the velocity of GNSS and leveling, but also improve the reliability of height variety in Shandong province.

Ancient building reconstruction based on 3D laser point cloud combined with UAV image

ZHANG Wenchun, FAN Hongyang, LIU Yongji, LIN Nan, ZHANG Haiming

2019, 0(11):  130-133,144.  doi:10.13474/j.cnki.11-2246.2019.0366

Asbtract ( )  

References | Related Articles | Metrics

The protection of ancient buildings is a hot research topic in the field of surveying and mapping. Non-contact measurement is a powerful measure to overcome the lack of digitalization of traditional methods and easily cause "secondary damage". Taking the aliens of No. 99 Hongxia street in Harbin as an example, this paper proposes a research project of combining 3D laser scanning technology with UAV aerial survey technology to reconstruct ancient buildings. Based on the point cloud data and image data of the ancient building acquired by the 3D laser scanner and the drone, the point cloud data is used to generate the orthophoto image and the flat, vertical, and sectional images are created, and the 3D model is created, and finally the building is measured in the field. Dimensional data is a reference analysis that yields drawing and model errors. The results show that the 3D laser point cloud combined with the UAV image can efficiently restore the architectural drawings and create a high-precision and refined 3D model, which provides a new thinking mode for the protection of ancient buildings.

Applicability of urban built-up area extraction based on remote sensing image and POI data: a case study of Shenyang

WU Xinyu, SUN Lishuang, XIE Zhiwei, ZHANG Danhua, YU Lili

2019, 0(11):  134-136,159.  doi:10.13474/j.cnki.11-2246.2019.0367

Asbtract ( )  

References | Related Articles | Metrics

The development status of urban built-up areas is an important part of geographic condition monitoring. This paper extracts urban built-up areas based on remote sensing image data and POI data, and studies their applicability. Shenyang is chosen as the research area, and 2016 remote sensing image data and POI data are selected as data sources for comparative study. Firstly, the remote sensing image data and POI data are preprocessed. Secondly, the built-up area of remote sensing image is extracted by supervised classification method. Then, the POI data are analyzed by kernel density estimation method and the built-up area is extracted. Finally, the applicability of these two data is compared and analyzed by superposition analysis method. The results show that using remote sensing image data as data source can reflect the development status of urban built-up areas comprehensively and objectively, and the urban built-up areas extracted from POI data have strong economic attributes, which can well reflect the economic active areas in cities.

Research on large scale mapping technology using three-dimensional model of UAV tilt photography

SHI Yuzheng, ZHANG Shuling, WANG Ying, LAI Jiwen

2019, 0(11):  137-140.  doi:10.13474/j.cnki.11-2246.2019.0368

Asbtract ( )  

References | Related Articles | Metrics

Based on the large-scale mapping technology of the 3D model of the UAV tilt photography, the large-scale mapping system is developed by using innovative techniques such as data denoising optimization, main baseline extraction and optimization. The system can solve the problems of large workload, large buildings in the old city, intensive conditions in the old city, closedness and privacy of the residents, complicated procedures and high cost in the conventional full field digital mapping method. Set strict rules and thresholds to eliminate gross errors and optimize combinations, ensure the quality of the baseline, ensure the accuracy of surveying and mapping results, and the level of research and development has reached the domestic advanced level.

Risk analysis of land subsidence in Hexi area in Nanjing based on multi-source data

ZHANG Peng, ZHU Bangyan, SUN Jingwen, WANG Xiao

2019, 0(11):  141-144.  doi:10.13474/j.cnki.11-2246.2019.0369

Asbtract ( )  

References | Related Articles | Metrics

Risk assessment of land subsidence is of great significance to urban public safety. In this paper, InSAR subsidence, geological data are combined to evaluate the risk of land subsidence in Hexi in Nanjing. Firstly, the subsidence information obtained by InSAR is used to establish a three-level multi-factor land subsidence risk assessment system by using analytic hierarchy process(AHP) in combination with the soft soil thickness, land use type, ground elevation and rail transit distribution information. Then, the risk degree of land subsidence is analyzed. Finally, the subsidence risk of rail transit is analyzed emphatically. The results show that the spatial characteristics of land subsidence risk in Hexi are obvious. The high-risk areas are mainly distributed in Jiangdong street, Fenghuang street and Mochouhu street with an area of about 6.4 km², among which the land subsidence risk of metro line 2 is relatively high.

Intelligent sensing of ecological environment information based on mobile GIS

YANG Zhi, ZHANG Hua, ZHANG Lei, WANG Cheng, ZHANG Chunju

2019, 0(11):  145-148.  doi:10.13474/j.cnki.11-2246.2019.0370

Asbtract ( )  

References | Related Articles | Metrics

With the rapid development of mobile Internet, people walk as "sensors" in society to create real-time, actual-environment and large-scale geographic information, especially for the geographic information of regional environments. These information has the characteristics of interaction, real-time, richness and sociality, and becomes gold mine in the eyes of data scientists. Based on the background of "Internet plus" era, with the maturity of mobile Internet, mobile GIS and LBS technology, this paper proposes an intelligent sensing method of ecological environment based on mobile GIS. It develops an APP based on the Android platform, which realizes the functions of querying environmental quality, consulting environmental pollution map, sharing and resolving environmental problems. We sense and obtain Eco-environmental information from the public perspective, provide real-time dynamic environment information querying for the public, and encourage the public to participate in environmental protection. Further, it can provide new method for controlling environmental pollution and obtaining geographic information resources.

Application of the geography condition monitoring results in agriculture and tourism

QI Zhonghua, QIU Jiannan, ZHANG Liren, WU Changjun

2019, 0(11):  149-152,162.  doi:10.13474/j.cnki.11-2246.2019.0371

Asbtract ( )  

References | Related Articles | Metrics

The purpose of geographic situation monitoring is to obtain the information of surface changing caused by natural,social and economic activities, including the spatial distribution characteristics, interrelationship of surface nature, human geographical elements and socio-economic information. It is an important part of governmental decision-making, enterprise management, industrial production and operation and people's life to provide data and decision-making basis. This paper discusses how to use the results of geographic situation monitoring to promote the development of agriculture and tourism, based on the data of geographic situation monitoring and combined with various surveying, mapping geographic information and technical means, in order to enhance the value of monitoring results and realize the fundamental transformation of the development mode of surveying and mapping geographic information.

Some thoughts on the Fourteenth Five-Year Plan of fundamental surveying and mapping

RUAN Yuzhou, WANG Chenyang

2019, 0(11):  153-155.  doi:10.13474/j.cnki.11-2246.2019.0372

Asbtract ( )  

References | Related Articles | Metrics

Focusing on clarifying the responsibilities and priorities of basic surveying and mapping in the business structure of natural resources management, and on how to better fulfill the legal requirements in accordance with the new Surveying and Mapping Law, the paper analyses the current situation of basic surveying and mapping, puts forward the basic thinking and main follow-up of the Fourteenth Five-Year Plan, and defines the focus of work and relevant measures. Relevant viewpoints have been reflected in the compilation of the Fourteenth Five-Year Plan for basic surveying and mapping.

Application of 3D laser technology in automatic measurement of sand-stone square

WANG Renyin, CHEN Rui, LI Kaiwei, YE Bo

2019, 0(11):  156-159.  doi:10.13474/j.cnki.11-2246.2019.0373

Asbtract ( )  

References | Related Articles | Metrics

In view of the new system of sand and stone industry, we will promote high-quality development of the industry, promote the transformation of the mechanism of sand and stone, and put forward suggestions and opinions on energy consumption indicators, comprehensive utilization of solid and waste construction, cultivation of demonstration enterprises, and models for the transformation and development of the sand and stone industry. This paper discusses the flow of sand square measurement technology based on three-dimensional laser scanner, and discusses the data collection, internal processing method and attention in the operation process based on the actual case. Finally, the advantages of 3D laser technology in the application of sand square measurement are summarized.

Methods and comparative analysis of tunnel structure section measuring

YANG Zhijian

2019, 0(11):  160-162.  doi:10.13474/j.cnki.11-2246.2019.0374

Asbtract ( )  

References | Related Articles | Metrics

The purpose of tunnel section measurement is to accurately measure the actual contour of the tunnel excavation and compare it with the design contour to calculate the over-underage. Section measurement according to the different instruments used, there are mainly cross-section method, total station method and 3D laser scanner method. This paper compares the working efficiency and measurement accuracy of these three methods, and draws some useful results in conclusion.