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1.
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. 相似文献
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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 相似文献
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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. 相似文献
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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。 相似文献
6.
Richard A. Snay 《Journal of Geodesy》1990,64(1):1-27
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 K0.7 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 K0.5. 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. 相似文献
7.
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。 相似文献
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Bela Szabo 《Journal of Geodesy》1962,36(3):221-226
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 相似文献
10.
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。 相似文献
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《Journal of Geodesy》1975,49(3):241-257
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. 相似文献
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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。 相似文献
17.
L. Hradilek 《Journal of Geodesy》1976,50(4):301-306
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. 相似文献
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B. Kasietczuk 《Journal of Geodesy》1997,71(3):131-136
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 相似文献
20.
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。 相似文献