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随着3G时代的到来,手机已经成为人们生活中不可缺少的工具,人们不再满足手机设备出厂时所固有的功能,而是希望像计算机一样能开发各种需要的应用软件。因此,基于手机平台的应用软件开发成为人们非常关注的领域。本文基于手机平台,利用J2ME编译环境开发了水准测量系统,为测量人员提供一整套水准测量基本功能,包括电子观测手簿、平差计算、图形显示等。试验表明,该系统使用方便,节省了外业人员工作量,现场计算测站误差与整体误差,大大提高了工作效率。 相似文献
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基于J2ME/Mobile SVG的手机地图服务 总被引:7,自引:0,他引:7
分析目前手机服务技术并选择J2ME利用手机上网方式提供地图服务,采用Mobile SVG组织地图数据,在此基础上设计基于J2ME/Mobile SVG的手机地图服务,并对其关键技术进行分析. 相似文献
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基于Java手机的地理信息服务探索 总被引:14,自引:1,他引:13
随着Internet和通讯技术的发展,移动用户利用手机、笔记本电脑、PDA、掌上电脑等移动终端通过无线网络接入Internet,从而方便的在移动中查询搜索自己感兴趣的信息.地理信息技术和Internet、通讯技术结合可以提供基于无线终端的移动的地理信息服务.介绍基于Java手机地理信息服务系统的特点,系统开发的难点,终端技术--J2ME技术,重点介绍一个服务器端采用J2EE体系,客户端采用J2ME技术的地理信息服务系统的实现. 相似文献
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根据目前手机软硬件发展水平,探讨了采用手机进行测量外业计算的可能性和必要性.介绍了手机测量计算软件的开发环境配置.通过导线测量计算、放样计算和边长交会计算三个实例,描述了手机测量计算Java程序的开发过程和计算软件应用实例.通过实践证明,利用手机进行科学计算,能够达到很高的精度,完全满足常用的测量计算需要,展现了手机这... 相似文献
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在分析目前地图服务存在问题的基础上,将网格技术应用到移动空间信息服务领域,研究了基于网格的位置服务原理和特点.针对地图服务存在的问题,提出了基于网格的地图服务,并通过与J2ME技术的结合实现了一个Java手机地图服务系统,可以改善地图服务的性能,提高位置服务的效率. 相似文献
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在测绘实际工作中,测绘人员经常会使用Microsoft Excel软件来进行函数计算。而有关Excel函数的使用,在高校培养方案确定的课程中却很少涉及。在教学过程中有必要加强学生对Excel函数应用能力的培养。《测量学》中的水准测量表格计算相对简单,可以作为Excel表格函数使用的初步引导。而导线测量表格计算中函数使用较为复杂,应该作为进一步加强学生应用能力的实践训练对象。 相似文献
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一个物流配送优化算法 总被引:13,自引:0,他引:13
分析并描述了终端物流配送体系,建立了终端物流配送优化模型。该模型是一个复杂的带约束的多旅行商问题,属于非确定性多项式(NP)完全问题。基于集合分划、启发式贪心策略和边缘交换算法给出一种可行的优化算法。 相似文献
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Ultra-high degree spherical harmonic analysis and synthesis using extended-range arithmetic 总被引:3,自引:2,他引:1
We present software for spherical harmonic analysis (SHA) and spherical harmonic synthesis (SHS), which can be used for essentially
arbitrary degrees and all co-latitudes in the interval (0°, 180°). The routines use extended-range floating-point arithmetic,
in particular for the computation of the associated Legendre functions. The price to be paid is an increased computation time;
for degree 3,000, the extended-range arithmetic SHS program takes 49 times longer than its standard arithmetic counterpart.
The extended-range SHS and SHA routines allow us to test existing routines for SHA and SHS. A comparison with the publicly
available SHS routine GEOGFG18 by Wenzel and HARMONIC SYNTH by Holmes and Pavlis confirms what is known about the stability of these programs. GEOGFG18 gives errors <1 mm for latitudes [-89°57.5′, 89°57.5′] and maximum degree 1,800. Higher degrees significantly limit the range
of acceptable latitudes for a given accuracy. HARMONIC SYNTH gives good results up to degree 2,700 for almost the whole latitude range. The errors increase towards the North pole and
exceed 1 mm at latitude 82° for degree 2,700. For a maximum degree 3,000, HARMONIC SYNTH produces errors exceeding 1 mm at latitudes of about 60°, whereas GEOGFG18 is limited to latitudes below 45°. Further extending the latitudinal band towards the poles may produce errors of several
metres for both programs. A SHA of a uniform random signal on the sphere shows significant errors beyond degree 1,700 for
the SHA program SHA by Heck and Seitz. 相似文献
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周文生 《武汉大学学报(信息科学版)》1991,(1)
本文揭示了航带法平差中所存在的一些问题,由此提出了改善航带法平差的附有共线条件的航带法平差,并且对该平差方法的数学模型、法方程的结构及其解算等作了详细的分析。最后用这种平差方法对一组实测数据进行了试验,其结果表明,该平差方法不但具有运算简单,对计算机内存要求较少的优点,而且还具有较高的平差精度。 相似文献
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利用现有重力场模型求定CHAMP卫星加速度计修正参数 总被引:3,自引:0,他引:3
CHAMP卫星加速度计数据的标定是通过确定其尺度因子和偏差参数来完成的.本文基于能量守恒方程,给出利用现有重力场模型标定CHAMP卫星加速度数据的基本原理和数学模型;提出相邻历元间差分算法,大大简化了观测方程,同时避免积分常量的计算.该算法既能同时解算尺度因子和偏差参数,也可任意求解其中之一.基于实测的CHAMP卫星加速度数据,利用EGM96模型和最新公布的EIGEN-2模型进行计算与比较,验证该方法的有效性. 相似文献
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Gravity data observed on or reduced to the ellipsoid are preferably represented using ellipsoidal harmonics instead of spherical harmonics. Ellipsoidal harmonics, however, are difficult to use in practice because the computation of the associated Legendre functions of the second kind that occur in the ellipsoidal harmonic expansions is not straightforward. Jekeli’s renormalization simplifies the computation of the associated Legendre functions. We extended the direct computation of these functions—as well as that of their ratio—up to the second derivatives and minimized the number of required recurrences by a suitable hypergeometric transformation. Compared with the original Jekeli’s renormalization the associated Legendre differential equation is fulfilled up to much higher degrees and orders for our optimized recurrences. The derived functions were tested by comparing functionals of the gravitational potential computed with both ellipsoidal and spherical harmonic syntheses. As an input, the high resolution global gravity field model EGM2008 was used. The relative agreement we found between the results of ellipsoidal and spherical syntheses is 10?14, 10?12 and 10?8 for the potential and its first and second derivatives, respectively. Using the original renormalization, this agreement is 10?12, 10?8 and 10?5, respectively. In addition, our optimized recurrences require less computation time as the number of required terms for the hypergeometric functions is less. 相似文献
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Short-wavelength Spectral Properties of the Gravity Field from a Range of Regional Data Sets 总被引:1,自引:0,他引:1
Jakob Flury 《Journal of Geodesy》2006,79(10-11):624-640
The GRACE (gravity recovery and climate experiment) and GOCE (gravity field and steady-state ocean circulation explorer) dedicated gravity satellite missions are expected to deliver the long-wavelength scales of the Earth’s gravity field with extreme precision. For many applications in Earth sciences, future research activities will have to focus on a similar precision on shorter scales not recovered by satellite missions. Here, we investigate the signal power of gravity anomalies at such short scales. We derive an average degree variance and power spectral density model for topography-reduced gravity anomalies (residual terrain model anomalies and de-trended refined Bouguer anomalies), which is valid for wavelengths between 0.7 and 100 km. The model is based on the analysis of gravity anomalies from 13 test regions in various geographical areas and geophysical settings, using various power spectrum computation approaches. The power of the derived average topography-reduced model is considerably lower than the Tscherning–Rapp free air anomaly model. The signal power of the individual test regions deviates from the obtained average model by less than a factor of 4 in terms of square-root power spectral amplitudes. Despite the topographic reduction, the highest signal power is found in mountainous areas and the lowest signal power in flat terrain. For the derived average power spectral model, a validation procedure is developed based on least-squares prediction tests. The validation shows that the model leads to a good prediction quality and realistic error measures. Therefore, for least-squares prediction, the model could replace the use of autocovariance functions derived from local or regional data. 相似文献