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高层建筑物中点恢复的测量方法是在负一层测定该建筑物的中点,再引到四层楼顶,最后重新确定施工放样数据,保证该建筑物的设计要求和施工监测。 相似文献
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MA Dingguo CHEN Jie ZHANG Wenjiang ZHENG Lin LIU Ying 《地理学报(英文版)》2007,17(3):269-284
This paper quantitatively explores farmers＇ vulnerability to flood in the Poyang Lake Region （PLR） with the supports of GIS spatial functions. The analysis consists of three major steps, which is based on the spatial unit of township. Firstly, the spatial extent and characteristics of flood risk areas were determined using a digital elevation model （DEM） derived from the 1：50,000 topographic map. Secondly, for each of the township, six indices indicating the economic activities of local farmers were calculated. These indices are： rural population proportion, cultivated land proportion, GDP per unit area, employment proportion of primary industry, net rural income per capita and agricultural income proportion. These six indices were then normalized and used for later vulnerability assessment. Thirdly, the normalized indices （as GIS data layers） were overlaid with the flood risk areas to produce the risk coefficient for each township and to calculate the overall vulnerability for each township. The analysis results show that in the PLR there are high flood risk areas where the farmers＇ livings are seriously influenced or threatened. About 55.56% of the total 180 townships in the flood risk areas have a high degree of flood vulnerability. The townships under flood risk are mainly distributed in the areas around the Poyang Lake and the areas along the ＂five rivers＂. 相似文献
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未测一连接边的无定向导线计算及精度分析 总被引：1，自引：0，他引：1
本文介绍了一种新型导线——未测一连接边的无定向导线的计算原理,并进行了精度分析。论述并验证了它的实用性,阐述了它与边角后方交会的通用性。 相似文献
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总结三维激光扫描技术在文物建筑测绘中应用的技术路线,运用传统大地测量学中控制测量和误差传播的相关理论,重点分析三维激光扫描技术中的坐标转换和点云最弱点位置及精度问题。 相似文献
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Changming WANG Jianping CHEN Pulin LI Hao ZHANG Lijian YANG 《东北亚地学研究》2006,9(2):189-193
Groundwater pollution has serious influences on programming and development for a city.So it has a special importance to assess reasonably the vulnerability to pollution for urban groundwater.DRASTIC is an effective method for groundwater vulnerability assessment,which has been adapted in USA and Europe countries.In this paper,DRASTIC method is applied in vulnerability assessment of shallow groundwater environment in Kunming.A total of 1 339 units are divided in this area and the grade of each unit for seven indexes is determined.Then vulnerability zones are divided in the area by DRASTIC value,which has an important meaning to city programming. 相似文献
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本文将测量控制网及网中点与点之间的相互关系表示成模糊矩阵形式。通过对模糊矩阵中的元素进行分析，推出了控制网中最弱点的位置，并结合实例进行了论证。 相似文献
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本文简述了间接平差中能对大规模网同时考虑观测误差和起始误差影响的精度估算新方法;计算分析了几类典型图形中起始误差与观测误差影响的比例关系;用两种不同方法计算分析了我国天文大地网的最弱点点位中误差,精度为±2.0m。 相似文献
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