一种基于点对应的激光扫描仪外方位参数检校方法     

杨长强  叶泽田 《测绘科学》2011,36(5):190-192

本文设计了一种检校标志用以激光扫描仪的检校,利用三平面相交得到检校标志中的特征点在激光扫描仪坐标系和全站仪坐标系中的坐标值,根据点点对应采用平差的方法计算得到两坐标系之间的变换矩阵,最后给出实验结果和精度分析.  相似文献   

几种模型在平面坐标转换中的应用     

姚朝龙  刘立龙 《地理空间信息》2011,9(2):64-66

针对在平面坐标转换时选取不同模型将得到不同的转换精度,通过所编程序进行实验,对比了四参数模型、六参数模型和二次曲面模型的转换精度.实验表明,当合理选择转换点时二次曲面模型在平面坐标转换中精度高于四参数模型和六参数模型的转换精度.  相似文献   

未知空间参考系大比例尺地形图的坐标转换     

胡海驹  魏王宣 《地理空间信息》2011,(5):74-77

针对未知空间参考系的大比例尺地形图测绘成果,通过数值模拟计算得到了各种参数对转换结果的影响,结果表明,三维四参数模型不适用于未知空间参考系的坐标转换,椭球参数对平面四参数转换结果的影响完全可以忽略不计。进而通过高斯投影长度变形公式与高斯投影公式得出了近似中央子午线的计算关系式,并用实际数据进行了算例验证,结果表明本文的...  相似文献   

一种基于全站仪的机体受载形变实时测量方法     

惠广裕  武瑞娟  白仲斐 《地理空间信息》2011,(5):35-38

飞机强度试飞中,机体形变测量结果是判别其是否为危及飞行安全、有碍操纵等有害永久形变的依据。根据全站仪测量定位原理,采用同名点多视站数据拼接方法,基于徕卡全站仪GeoCOM接口技术,提出了一种基于全站仪进行机体受载形变实时测量方法。实践证明,此方法不但保证了数据精度,还能实时给出形变分析结果,大大提高了工作效率,对今后全...  相似文献   

基于空间平滑法的武汉城市圈地震危险性概率分析     

魏运浩  姚运生  王秋良  檀玉娟 《地震研究》2011,34(3):286-290

以武汉城市圈为研究对象,利用空间平滑方法建立了区域的两个地震活动性模型,计算了50年超越概率10％的基岩峰值加速度分布图,与地震动参数区划图的对比表明,其结果能合理反映区域的地震危险性水平.在弱震活动区,基于空间平滑法的地震危险性概率计算能给出可靠的地震动参数.  相似文献   

大同及邻区地震网格化相关分析及预测意义     

沙海军  刘冬英 《中国地震》2011,27(4):403-409

利用华北地区1970～2009年的ML3.0以上地震资料,用相关分析方法,研究了大同及邻区的中小地震空间分布模式及其在该区中强地震前的异常情况.在确定空间范围、时间窗和时间滑动步长后,将地震的空间分布进行网格化再转化为序列;对一个时段内及其稍长时段内的地震空间分布进行序列化,计算两个序列的相关系数并分析相关系数在中强地震前的变化.结果表明,在以1989年大同-阳高5.9级地震震中为中心,取经向和纬向均为1.6°的矩形区域,时段长为3600天,稍长时段取3700天,滑动步长取100天的情况下,1980～2009年的相关系数的时间序列值基本在0.94 ～ 1.00之间波动,但在1989年山西大同-阳高5.9级、1991年山西大同5.8级与1999年山西浑源5.6级地震前2年均出现过相关系数小于0.94的异常现象,表明地震的空间分布出现明显变化.分析相关系数异常对于中强地震的前兆意义,得到以下3点认识:①大同及周边地区的中强地震前,可将中小地震空间分布模式发生的显著变化,作为2年尺度的震兆异常,为该区中期地震预测提供时间的参考;②考虑到研究区的限定范围为震中周边0.8°以内,地震时空分布的相关分析结果对于地震地点的预测也是有意义的;③相关分析可以为识别此类地震空间分布模式的异常变化提供帮助.  相似文献   

Scale‐Dependent Variability of As and Heavy Metals in a River Elbe Floodplain     

Dana Zimmer  Kristian Kiersch  Christel Baum  Ralph Meissner  Robert Müller  Gerald Jandl  Peter Leinweber 《洁净——土壤、空气、水》2011,39(4):328-337

  相似文献   

Asynchrony of spring phytoplankton response to temperature driver within a spatial heterogeneity bay of Three-Gorges Reservoir, China   总被引：3，自引：0，他引：3  

Yaoyang Xu  Qinghua Cai  Lin Ye  Meiling Shao 《Limnologica》2011,41(3):174-180

The increased air temperature is expected to have important driver on spring phytoplankton dynamics. To test whether spatial heterogeneity modifies the synchronous responses of phytoplankton to regional temperature driver, we evaluate temporal coherences for physical factors (temperature, water stability and non-algal light extinction), nutrients (nitrogen, phosphorus and silicon), and biomass and density of phytoplankton by Pearson correlation analysis and synchrony for phytoplankton community dynamics by Mantel test and nonmetric multi-dimensional scaling (NMS), during spring bloom (February 23–April 28, 2005) within Xiangxi Bay, a high spatial gradient bay of Three-Gorges Reservoir (China). The high level of temporal coherences for surface water temperature (r = 0.946, p < 0.01) and relative water column stability (r = 0.750, p < 0.01) were found between pair sites (A and B), in which the increase trends occurred with increase in regional air temperature during the study period. However, the low synchrony for phytoplankton dynamics were indeed observed between Site A and B, especially for the density of common dominant taxa (Cyclotella spp.: r = 0.155, p = 0.388) and community structure (Mantel test: r = 0.351). Moreover, the local habitat characteristics such as nutrient (nitrogen and phosphorus) and non-algal light extinction showed low levels of temporal coherence. It indicated that local community of phytoplankton varies rather independently within the single lentic bay with high spatial heterogeneity and that dispersal of algal organisms among locations cannot overwhelm out these local dynamics. Contrary to many studies, the present results argued that, in a small geographic area (i.e., a single reservoir bay of approximately 24 km length), spatial gradients also may influence spring phytoplankton response to regional temperature driver.  相似文献   

In situ cyclic tests on existing stone masonry walls and strengthening solutions     

Alexandre A. Costa  António Arêde  Aníbal Costa  Carlos Sousa Oliveira 《地震工程与结构动力学》2011,40(4):449-471

The present work reports on an in situ experimental test campaign carried out on abandoned traditional masonry houses after the 9th July 1998 earthquake that seriously hit the Faial island of Azores. For the testing purposes, an experimental test setup was developed based on a self‐equilibrated scheme, which is herein described reporting on the advantages and drawbacks of this in situ test setup. Five specimens were tested aiming at characterizing the out‐of‐plane behavior of stone masonry walls and strengthening solutions recommended for post‐earthquake interventions. A detailed comparison between solutions' efficiency is presented including a cost vs benefit analysis. In order to assess the efficiency of the developed test setup for other applications on stone masonry walls, an in‐plane test on an existing URM panel is also presented. Several related issues are discussed, namely the advantages of dealing with the real boundary conditions and the capacity of providing valuable information of the response, as well as a detailed analysis of the obtained results. The authors believe that this work provides an increase in knowledge on the seismic behavior of the existing masonry constructions, resulting from the development of an in situ test setup and the efficiency quantification of strengthening solutions. Therefore, the work is thought to positively contribute for the preservation of architectural heritage and for its seismic vulnerability reduction. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

岩土力学和工程试验测试设备研发进展报告     

邵龙潭  祝艳凤  郭晓霞  桑勇  刘潇  黄川  华承博  冯忠帅 《冰川冻土》2011,33(4):953-958

目前,世界上比较成熟的先进土工测试仪器生产和研发机构主要在英国、美国、日本和俄罗斯等,我国相应的土工测试仪器基本上依赖进口或者委托国外研发机构开发,不仅价格昂贵,而且维修和维护均不方便．以引入三轴土样变形数字图像测量技术为牵引,研发团队从2000年开始便开展土工试验仪器设备的改进和研发工作．主要介绍近年来自主研发的一系...  相似文献