地理实体具有对象化、结构化、语义化、机器可读等显著特征,具备业务语义的地理实体在自然资源业务审批、监管和决策分析中可以发挥重要的信息载体和联结纽带作用.语义化内容与应用需求密切相关,本文面向"三旧"改造成效评估业务,探索地理实体的语义化内容获取、表达及成果应用的实现路径,为"三旧"改造成效评估业务提供了新型解决思路,助力提升该项业务的精细化管理水平.
This paper addressed the focus of existing domestic research on the application issues of three-dimensional(3D)laser scanners in engineering by re-examining the development history of 3D laser scanners.The fundamental ranging principles of commonly used methods in 3D laser scanners,such as triangulation,phase ranging,and pulse ranging,were introduced.3D laser scanners were further classified into dynamic 3D laser scanners,static 3D laser scanners,and handheld 3D laser scanners,based on different carriers.To further leverage the value of 3D laser scanners,it is necessary to establish appropriate calibration standards for different types of instruments,ensuring that the accuracy of the devices meets the precision requirements of the objects being measured.In data processing,the development of improved software was essential to address the multipath effect and data void issues present in the measurement data.
As a bridge between remote sensing data and industry applications,remote sensing data processing software plays an irreplaceable role in the development of remote sensing industrialization in China.In order to reduce the dependence on foreign remote sensing data processing software at source and meet the growing national economic and security needs,it is necessary to carry out research on the application of domestic remote sensing software in the practical teaching of surveying and mapping majors and promote the use and development of domestic remote sensing software in surveying and mapping majors in colleges and universities.This paper analyzed the necessity and applicability of pixel information expert(PIE)domestic remote sensing data processing software in college teaching from the teaching needs of remote sensing practical courses of surveying and mapping undergraduate majors,made full use of experiential teaching concept and flipped classroom,designed relevant teaching cases and conducts experiments in undergraduate teaching practice,and provided important reference for the promotion and application of PIE in experiential practical teaching of surveying and mapping majors.At the same time,it provided an important reference to promote the development of domestic remote sensing software in practical teaching.
Aiming at the deformation monitoring problem of dam safety operation,this study of dam deformation detection method was carried out based on small baseline subset-interferometric synthetic aperture radar(SB AS-InS AR)technology.The dam differential interferometric phase diagram was generated by setting the time baseline threshold.The improved Goldstein filter algorithm was realized to filter the differential interferometric phase diagram of the dam.Using the minimum discontinuous region growth unwinding algorithm,the phase unwinding dam differential interferometric phase diagram was presented.The high coherence points were selected in the dam phase unwinding diagram by the coherence coefficient threshold method.The mathematical model of elevation measurement and estimation for dam deformation detection and monitoring was established.Through the singular value decomposition method,the mathematical model was solved to realize the dam detection and monitoring results.Experiments showed that the method could generate dam differential interferogram effectively and remove the internal noise of dam differential interferogram.It could effectively detect and monitor the shape variables of each monitoring point in the dam.
In view of the shortage that the optical forest canopy gap rate extraction method is greatly affected by weather,this paper proposed a three-dimensional volumetric model method for forest canopy extraction based on light detection and ranging(LiDAR)point cloud data,and used point cloud projection and DHP for comparison.The results showed that the variation trend of gap rate extracted from different volume cell sizes was basically the same.The larger the volume cell size was,the smaller the gap rate extracted was.When compared with point cloud projection and DHP,the correlation between the extracted results of the proposed method and those of the two methods gradually increased with the increase of the volume element.When the top Angle was 0°～80° and 10°～65°,the correlation coefficient was above 0.91,indicating that the proposed method could be used to extract the forest canopy gap ratio.
