Building 3D cadastral system based on 2D survey plans with SketchUp

Three-dimensional (3D) land development and utilization has become the trend for urban planning in the current metropolis.This paper presents a method for building a 3D cadastral management system from survey plans with SketchUp.It concentrates on the geometric representation and topological consistent maintenance of 3D cadastral objects.In this system a complete topological model is built to express the body construction and spatial relationships among 3D property units.SketchUp is used to automatically construct 3D models with attributes and thematic information from 2D survey plans.Spatial topologic relationships and operations are analyzed with the programming and development of Ruby language.The resulting system can manage 3D cadastral objects and manipulate them with spatial operations to support spatial analysis.     

Real time estimation of position and the gravity vector with an inertial survey system

Based on sine functions for fitting horizontal velocity errors in an inertial survey system and a step or slope function approximation of the vertical deflection between stops, a positioning accuracy of 10 m (CEP) can be achieved with a car-borne system – a modified -21 aircraft navigation system, with a 10 min travel period between Zero Velocity Update Times (ZUPTs) and a total 1.5 hour survey time. A rough estimation of the vertical deflection can also be expected in real time out of the approach. Also a forward-backward-forward run is presented which demonstrates determination of the gravity anomaly. Received 10 March 1995; Accepted 8 July 1996     

Analysis of the heading sensitivity in the Litton inertial survey system

The straight line concept which has developed as a practical design restriction in intertial surveys with the Litton System is not only cumbersome in the planning stage but also often affects the economy of the survey adversely. A more flexible use of the system is therefore desirable. The analysis of test data taken along a well-controlledL-shaped traverse near Ottawa indicates that software modifications can eliminate a large part of the errors the to heading sensitivity. The paper discusses the design of an appropriate smoother and ways to find its model structure and its weighting from a series of test runs. Results show that the maximum standard deviation along anL-shaped traverse of100 km length is about half a metre. Further improvements are envisaged by changes in the survey procedures and a more effective use of the filter output. Optimal smoothing is not possible at present and would require a redesign of the filter output.     

工程测量、地籍测量中用坐标计算面积的代数精确度

讨论用坐标进行面积计算的代数精确度,提出在工程测量、地籍测量实践中对不规则图形的面积进行测量和计算时应注意的问题。     

全站仪地籍碎部测量中的错误分析与改正

目前全站仪在城镇地籍测量,尤其在地籍碎部测量中广泛应用。文中分析采用全站仪进行地籍碎部测量时不同作业状态下可能出错的情况,即定向时错误输入坐标或定向点位置错误、测量期间全站仪微动或换电池等。并揭示出现错误的根源、特征及相应检查方法,最后提出对全站仪地籍碎部测量中产生的错误进行改正的方法,并对其做了精度验证。     

Accuracy analysis for the NAD 83 geodetic reference system

The North American Datum of 1983 (NAD 83) provides horizontal coordinates for more than 250,000 geodetic stations. These coordinates were derived by a least squares adjustment of existing terrestrial and space-based geodetic data. For pairs of first order stations with interstation distances between 10km and 100km, therms discrepancy between distances derived fromNAD 83 coordinates and distances derived from independentGPS data may be suitably approximated by the empirical rulee=0.008 K^0.7 where e denotes therms discrepancy in meters and K denotes interstation distance in kilometers. For the same station pairs, therms discrepancy in azimuth may be approximated by the empirical rule e=0.020 K^0.5. Similar formulas characterize therms discrepancies for pairs involving second and third order stations. Distance and orientation accuracies, moreover, are well within adopted standards. While these expressions indicate that the magnitudes of relative positional accuracies depend on station order, absolute positional accuracies are similar in magnitude for first, second, and third order stations. Adjustment residuals reveal a few local problems with theNAD 83 coordinates and with the weights assigned to certain classes of observations.     

广州市轨道交通首级精密控制网测量

根据广州市轨道交通2015年建设线路的布局要求以及技术难点,研究项目技术路线的制定以及GPS平面控制网和二等水准控制网的建设实施。项目充分利用一系列新技术手段,解决新旧控制网的整合协调以及精度一致性等技术难题,建设统一覆盖原有线路和新规划线路的精密控制网。     

北京同步辐射装置准直测量控制网的设计与优化

在北京同步辐射装置升级改造中,为提高元件的安装精度,同时兼顾未来新增光束线的建设需要,在实验大厅建立了准直测量控制网,作为设备定位、调校、安装和变形监测等工作的基础。本文重点介绍该控制网的设计、优化与观测结果分析,特别阐述了激光精密测量技术的应用,以及对点位密度、测量精度及可靠性的控制。     

Application of the gravimetric method for a world geodetic system

It is desirable to unify the various unconnected geodetic systems of the world into a common earth-centered world datum. This can be achieved by gravimetric means. The gravimetric deflection components have been determined at a certain number of stations in different areas. Utilizing the differences between the gravimetric and astro-geodetic deflection components, the reduction of the major geodetic datums into a common world geodetic system has been accomplished. Geophysical Studies Section Aeronautical Chart and Information Center Presented at the Twelfth General Assembly of the International Union of Geodesy and Geophysics Helsinki, Finland     

RTK技术在商丘市GPS控制网建立中的试验与研究

对影响GPSRTK测量精度和可靠性的因素进行了分析,并结合商丘市一级GPS网具体实例,通过RTK与静态定位成果精度的分析比较,总结出RTK在城市一级GPS控制网作业中应采取的观测措施。     

长大隧道洞内自由测站边角交会网平面控制测量

为了减小长大隧道洞内控制网中的横向贯通误差,文章提出一种隧道洞内平面控制测量新方法——自由测站边角交会网.文中介绍了自由测站边角交会网的网型特点、外业观测方法和内业数据处理方珐,并提出了自由测站边角交会网的附合路线闭合差和横向贯通误差计算等方法.通过对洞内横向贯通中误差进行估算并结合仿真测量实验,验证了自由测站边角交会网应用于隧道洞内平面控制中的可行性,实验表明,自由测站边角交会网在削减横向贯通误差等方面,要优于传统的导线网.     

无砟轨道基桩控制网测量技术探讨

轨道的高平顺性是客运专线无砟轨道最突出的特点之一。因此,需要建立高精度的铺轨基桩控制网。基桩控制网通常是按五等导线测量的方法进行布设,本文提出在导线基础上采用边角后方交会法来加密,通过运用原始数据误差理论和仿真实验的方法对无砟轨道控制基桩网的新旧两种测量技术进行对比,结果显示:采用边角后方交会法加密的控制网将得到更高的相对点位精度,具有更好的平顺性指标。这一结论对我国客运专线无砟轨道施工控制网的建设或许有参考价值。     

基于CGCS2000下地方大地坐标基准的建立与应用

随着现代空间定位技术的发展,原有地方独立坐标系统和控制测量成果存在诸多的问题,迫切需要建立基于CGCS2000下的新一代地方大地坐标基准。文中对地方坐标系的建设要求进行分析,研究新一代地方坐标系的参数选择和首级控制网的布设方法,并运用实际案例进行说明。     

Alignment of geodetic and satellite coordinate systems to the average terrestrial system

The parallelism of geodetic and satellite systems to the average terrestrial system is examined, under the assumption that a geodetic system is a fixed framework invariant with respect to geodetic network adjustment. In this case a geodetic system is rotated with respect to the average terrestrial system only about the ellipsoid normal of the initial point. The method is demonstrated using coordinates and covariance matrices for BC-4 and SECOR satellite tracking stations computed by Mueller and his co-workers. It is shown that the NAD geodetic system is scaled significantly larger than the satellite systems; the SECOR satellite systems have significant Z-rotations with respect to the average terrestrial system; and the ETH geodetic system may have a significant rotation with respect to the average terrestrial system.     

GPS测量在石佛寺水库施控网中的应用

ＧＰＳ技术在水利水电工程测量中已得到广泛应用,本文通过利用ＧＰＳ建立石佛寺水库施控网的实践,探讨了ＧＰＳ网的布设、实施、数据处理、平差等几方面的有关问题。     

Closed formulas for the direct and reverse geodetic problems

A new solution of the direct and reverse geodetic problems has been deduced without series expansion or coordinate transformation. The unknown parameters are directly expressed as explicit functions of the given parameters; the forms of the functions are closed formulas deduced by elementary mathematics using the chord of normal section. Numerical examples prove that the formulas are valid for distances from 40 km to 15 000 km on the surface of the ellipsoid.     

南京长江三桥钢索塔拼装测量控制网的建立

南京长江三桥是我国首座主塔采用钢结构形式的特大型斜拉桥。根据钢索塔拼装测量的精度要求,介绍了该桥首级控制网的概况,对钢索塔架设专用控制网的网形选择、方案设计、观测方法和数据处理进行了探讨。实践证明,所采取的专用控制网布设方法和测量方案是合理的,对今后类似工程具有借鉴意义。     

Estimation of asymmetry and kurtosis coefficients in the process of geodetic network adjustment by the least-squares method

 This paper presents an extension of the geodetic network adjustment model. The proposed extension makes possible the estimation of the 3-rd and 4-th central moments for the vector of measurement errors in the process of network adjustment by the least-squares method with application of orthogonal matrices. It allows to estimate the asymmetry and kurtosis of the measurement errors distribution. Received 13 April 1993; Accepted 8 July 1996     

过山车钢结构精度测量及局部坐标系数据应用

常规基于人工的坐标分解计算,在应对逐渐提升的建造要求及特殊产品的应用需求时,存在效率不高、人为误判等情况,本文通过对局部坐标分解应用进行研究及自动坐标分解与重新定向,有效解决了过山车类复杂结构建造尺寸精度管控过程中数据的修正及合格判定问题,为同类复杂空间钢结构的高精度测量检验偏差修正积累了丰富的应用经验。