论导线测角粗差的产生及其影响     

魏炳乾  石忠科  夏双喜 《海洋测绘》2006,26(2):9-12

针对导线测量中出现的测角粗差,对粗差的产生原因、有无粗差的坐标关系进行了分析,对粗差判据方法进行了理论推证、实例验证和讨论,证实了该方法具有理论的完整性和实际的可操作性,并对减少粗差出现的措施提出了建议。  相似文献   

利用泉水长观资料计算降水入渗系数——以务川自治县大竹园铝土矿区岩溶充水矿床为例     

黄作明 《矿产与地质》2016,(2):251-254

务川自治县大竹园铝土矿区为高山台地向斜正地形,岩溶充水矿床,水位埋藏较深,大气降水是地下水的唯一补给源,北、东、西为陡崖或陡坡,崖脚为矿系和隔水层,沿陡崖上部边缘分布一条开口向西的地表分水岭,形成完整的水文地质单元,地下水在向斜内由东向西汇集于梅古洞排泄。铝土矿层直接顶板梁山组(P_2l)页岩,厚度小,不连续,其上部茅口栖霞组(P_2m+q)灰岩强含水层与矿层直接接触,并且岩溶管道发育。因此,计算矿坑涌水量的方法用水均衡法较为恰当,即利用泉水观测资料计算入渗系数,从而达到预测矿坑涌水量、评价含水层富水性的目的。  相似文献   

Prediction of relative crest settlement of concrete-faced rockfill dams analyzed using an artificial neural network model   总被引：2，自引：0，他引：2  

Yong-Seong Kim  Byung-Tak Kim   《Computers and Geotechnics》2008,35(3):313-322

A neural network model has been developed for the prediction of relative crest settlement (RCS) of concrete-faced rockfill dams (CFRDs) using 30 databases of field data from seven countries (of which 21 were used for training and 9 for testing). The settlement values predicted using the optimum artificial neural network (ANN) model are in good agreement with these field data. A database prepared from reported crest settlement values of CFRDs after construction was used to train the ANN model to predict the RCS. It is demonstrated here that the model is capable of predicting accurately the relative crest settlement of CFRDs and is potentially applicable for general usage with knowledge of the three basic properties of a dam (void ratio, e; height, H; and vertical deformation modulus, E_V).

The performance of the new ANN model is compared with that of conventional methods based on the Clements theory and also with that of a proposed equation derived from the field data. The comparison indicates that the ANN model has strong potential and offers better performance than conventional methods when used as a quick interpolation and extrapolation tool. The conventional calculation model was proposed based on the fixed connection weights and bias factors of the optimum ANN structure. This method can support the dam engineer in predicting the relative crest settlement of a CFRD after impounding.  相似文献   

大型园林景观工程精细土方计算方法研究     

郑勇  钱烈涛  金海 《现代测绘》2008,31(6)

针对大型园林景观工程土方计算特点,提出了考虑复杂边界确定的三角网的土方计算方法。为提高计算精度,针对几种特殊地形,提出了高程点离散化的主要措施。结合实际工程运用所提出的土方计算方法和处理措施,实现了复杂区域的精细土方计算,满足了实际园林景观工程需要。  相似文献   

A Clustering‐Based Approach to the Capacitated Facility Location Problem1     

Ke Liao  Diansheng Guo 《Transactions in GIS》2008,12(3):323-339

This research develops a clustering‐based location‐allocation method to the Capacitated Facility Location Problem (CFLP), which provides an approximate optimal solution to determine the location and coverage of a set of facilities to serve the demands of a large number of locations. The allocation is constrained by facility capacities – different facilities may have different capacities and the overall capacity may be inadequate to satisfy the total demands. This research transforms this special location‐allocation problem into a clustering model. The proposed approach has two parts: (1) the allocation of demands to facilities considering capacity constraints while minimizing the cost; and (2) the iterative optimization of facility locations using an adapted K‐means clustering method. The quality of a location‐allocation solution is measured using an objective function, which is the demand‐weighted distance from demand locations to their assigned facilities. The clustering‐based method is evaluated against an adapted Genetic Algorithm (GA) alternative, which integrates the allocation component as described above but uses GA operations to search for ‘optimal’ facility locations. Experiments and evaluations are carried out with various data sets (including both synthetic and real data).  相似文献   

Uncertainty modeling and analysis of surface area calculation based on a regular grid digital elevation model (DEM)     

Chang Li  Sisi Zhao  Qing Wang  Wenzhong Shi 《International journal of geographical information science》2018,32(9):1837-1859

In the field of digital terrain analysis (DTA), the principle and method of uncertainty in surface area calculation (SAC) have not been deeply developed and need to be further studied. This paper considers the uncertainty of data sources from the digital elevation model (DEM) and SAC in DTA to perform the following investigations: (a) truncation error (TE) modeling and analysis, (b) modeling and analysis of SAC propagation error (PE) by using Monte-Carlo simulation techniques and spatial autocorrelation error to simulate DEM uncertainty. The simulation experiments show that (a) without the introduction of the DEM error, higher DEM resolution and lower terrain complexity lead to smaller TE and absolute error (AE); (b) with the introduction of the DEM error, the DEM resolution and terrain complexity influence the AE and standard deviation (SD) of the SAC, but the trends by which the two values change may be not consistent; and (c) the spatial distribution of the introduced random error determines the size and degree of the deviation between the calculated result and the true value of the surface area. This study provides insights regarding the principle and method of uncertainty in SACs in geographic information science (GIScience) and provides guidance to quantify SAC uncertainty.  相似文献   

冰川冰储量计算方法及发展趋势          下载免费PDF全文

高永鹏  姚晓军  刘时银  祁苗苗  宫鹏  安丽娜  李晓锋  段红玉 《干旱区地理》2018,41(6):1204-1213

冰川冰储量不仅是冰川的重要属性,而且是核算冰川水资源及预测冰川变化的基础数据,因此准确计算冰川冰储量及其变化具有重要的理论与现实意义。目前冰川储量估算的主要方法有经验公式法、冰厚模型估算法、探地雷达法;冰川储量相对变化计算方法有实地测量法和遥感监测法。通过系统分析和讨论各计算方法的原理、现状及存在的问题,以期为冰川储量估算提供方法参考。研究表明：对于冰川冰储量计算而言,经验公式法适用于区域性或全球性的冰川储量估算;模型估算法适用于个体或小范围冰川储量估算;探地雷达法适用于人类易到达区域冰川储量的估算。对于冰川冰储量相对变化计算,实地测量法适用于对精度要求高且满足实地测量条件的单条或中小型冰川,遥感监测法适用于全球性冰储量变化估算,但需改进算法和提高数据空间分辨率。目前,随着无人机技术的逐步应用,以及冰川流速等理论模型的提出,为冰川冰储量估算方法的发展提供了新契机。  相似文献   

GNSS偏心观测在卫星天线定位定向中的应用     

卢书 《测绘工程》2016,25(1):65-68

由于现地观测条件限制,GNSS天线无法架设在需要观测的目标点上,无法实现精确对中观测目标所对应的地面点中心,此时就需要进行GNSS偏心观测。文中从解决卫星天线定位定向的工程出发,研究GNSS偏心观测三角形法和经纬仪交会法计算归心元素。依据模拟实测计算结果以及实际卫星天线定位定向的结果,分析了两种方法的优缺点。  相似文献   

混沌时间序列相空间重构及特性识别     

张艳兰  栾元重  尹燕运  郭喜田  桑春阳  杜玉喜 《测绘科学》2016,41(4):15-18

相空间重构是混沌时间序列分析及预测的前提。针对地铁建设中地表沉降变形监测的弱信号数据处理问题,该文引入了混沌理论,通过采用自相关函数法和C-C法对比求得时间延迟τ,运用G-P方法和Cao方法求取嵌入维数m,从而对时间序列进行相空间重构;并通过求取最大Lvyapunov指数对时间序列进行混沌特性的判定识别。研究结论表明,系统的混沌特性,在研究地铁变形监测、运用混沌理论建模预测以及变形监测数据处理方面是值得重视的。  相似文献   

宁波沿海设计高潮位分析及查算图绘制          下载免费PDF全文

陈望春  徐琦良  王颖 《水文》2016,36(4):80-84

选取宁波沿海16个潮位站作为代表站,采用年最高潮位极值Ⅰ型分布法、年最高潮位P-Ⅲ型分布法、极值同步差比法、高潮同步相关法四种方法进行频率计算,根据计算结果绘制不同海域设计高潮位查算图,为宁波市沿海地区工程建设提供参考和依据,也便于查求无资料地区的设计高潮位。  相似文献