基于机载LiDAR数据的区域林木信息提取

本文对LiDAR数据的各种滤波方法以及多次回波特性进行了综合研究,提出一种基于其多次回波特性进行林木信息提取的方法,并对该方法的可行性进行了实例验证,为探索LiDAR数据的应用提供了新的思路。     

利用低空视频检测道路车辆

针对背景像素的移动,提出了SURF特征稳像和光流法向量相结合的新方法来解决低空视频的道路车辆检测。首先,检测两帧图像的SURF特征;再用最近邻匹配得到两幅图像的匹配点对;随后结合RANSAC和最小二乘法计算全局运动参数向量,获得稳定的帧;最后,根据稳定的帧计算光流法向量,并检测出运动车辆。实验结果表明,基于SURF算子的图像稳像算法在不损失稳像精度的前提下,能够提高图像稳像算法的速度,所提方法能够有效地检测出运动车辆。     

Life‐cycle reliability of RC bridge piers under seismic and airborne chloride hazards

Over the last two decades, the probabilistic assessment of reinforced concrete (RC) structures under seismic hazard has been developed rapidly. However, little attention has been devoted to the assessment of the seismic reliability of corroded structures. For the life‐cycle assessment of RC structures in a marine environment and earthquake‐prone regions, the effect of corrosion due to airborne chlorides on the seismic capacity needs to be taken into consideration. Also, the effect of the type of corrosive environment on the seismic capacity of RC structures has to be quantified. In this paper, the evaluation of the displacement ductility capacity based on the buckling model of longitudinal rebars in corroded RC bridge piers is established, and a novel computational procedure to integrate the probabilistic hazard associated with airborne chlorides into life‐cycle seismic reliability assessment of these piers is proposed. The seismic demand depends on the results of seismic hazard assessment, whereas the deterioration of seismic capacity depends on the hazard associated with airborne chlorides. In an illustrative example, an RC bridge pier was modeled as single degree of freedom (SDOF). The longitudinal rebars buckling of this pier was considered as the sole limit state when estimating its failure probability. The findings show that the life‐cycle reliability of RC bridge piers depends on both the seismic and airborne chloride hazards, and that the cumulative‐time failure probabilities of RC bridge piers located in seismic zones can be dramatically affected by the effect of airborne chlorides. Copyright © 2011 John Wiley & Sons, Ltd.     

测高数据不准时的直升机航空瞬变电磁一维反演方法理论研究

航空电磁勘探中,高度计显示的发射线圈高度数据往往是不准确的,这可能会影响反演结果,出现假异常现象。针对这一情况,提出了一种高度计数据不准确条件下的航空瞬变电磁资料一维反演方法,在重构地电参数的同时也对发射线圈高度值进行校正。由于航空电磁反演问题是典型的病态问题,使用正则化反演方法,正则化因子由数据目标函数与模型目标函数之间的关系以自适应方式给出,使得反演迭代能稳定进行。以直升机航空瞬变电磁资料反演为例,用理论模型响应数据加入噪声进行反演,结果表明,无论初始高度值是高于真值还是低于真值,该反演方法均能够较好地重构地下介质参数和发射线圈高度值;作为反演初值的发射线圈高度测量值越准确时,反演迭代收敛速度就越快,反演效果也越好。     

Validation of WRF model on simulating forcing data for Heihe River Basin

The research of coupling WRF (Weather Research and Forecasting Model) with a land surface model is enhanced to explore the interaction of the atmosphere and land surface; however, regional applicability of WRF model is questioned. In order to do the validation of WRF model on simulating forcing data for the Heihe River Basin, daily meteorological observation data from 15 stations of CMA (China Meteorological Administration) and hourly meteorological observation data from seven sites of WATER (Watershed Airborne Telemetry Experimental Research) are used to compare with WRF simulations, with a time range of a whole year for 2008. Results show that the average MBE (Mean Bias Error) of daily 2-m surface temperature, surface pressure, 2-m relative humidity and 10-m wind speed were ?0.19 °C, ?4.49 hPa, 4.08% and 0.92 m/s, the average RMSE (Root Mean Square Error) of them were 2.11 °C, 5.37 hPa, 9.55% and 1.73 m/s, and the average R (correlation coefficient) of them were 0.99, 0.98, 0.80 and 0.55, respectively. The average MBE of hourly 2-m surface temperature, surface pressure, 2-m relative humidity, 10-m wind speed, downward shortwave radiation and downward longwave were ?0.16 °C, ?6.62 hPa, ?5.14%, 0.26 m/s, 33.0 W/m² and ?6.44 W/m², the average RMSE of them were 2.62 °C, 17.10 hPa, 20.71%, 2.46 m/s, 152.9 W/m² and 53.5 W/m², and the average R of them were 0.96, 0.97, 0.70, 0.26, 0.91 and 0.60, respectively. Thus, the following conclusions were obtained: (1) regardless of daily or hourly validation, WRF model simulations of 2-m surface temperature, surface pressure and relative humidity are more reliable, especially for 2-m surface air temperature and surface pressure, the values of MBE were small and R were more than 0.96; (2) the WRF simulating downward shortwave radiation was relatively good, the average R between WRF simulation and hourly observation data was above 0.9, and the average R of downward longwave radiation was 0.6; (3) both wind speed and rainfall simulated from WRF model did not agree well with observation data.     

山东省区域地球物理场

山东省各岩石磁性及密度参数基本可分为高、中、低3类.山东省磁性结晶基底为泰山岩群、荆山群、胶东岩群、胶南岩群.以沂沭断裂带为界,山东省区域地球物理场分为鲁东区和鲁西区.鲁东区进一步划分为3个次级区,即北部区、中部区和南部区.鲁西区进一步划分为5个次级区,即鲁北重磁缓变区、鲁西南重高磁高区、中部弧形重磁场区、鲁西中部重低磁高区、鲁中南条带状重磁场区.各区地球物理场由于地质原因各具特点.山东省莫氏面总体呈东浅西深的缓变带,在该缓变带的背景上,呈周边地区条带状幔隆、中部幔坳的特征.山东省居里面呈近南北向带状分布,有德州聊城菏泽隆起带、滨州淄博滕州深坳带、蓬莱海阳千里岩响水隆起带.鲁中隆起北部碰撞带为山东省特殊的构造地带,其特征为侵入岩体沿该带断续出现、岩体围岩或岩体内铜及多金属矿化较为普遍、地热田沿该带时有分布、地形上为南部山区和北部平原的分界地带.胶莱盆地内,蓼兰-高密缺失莱阳群层位;中生代早期,盆地东北部与西南部是盆地的沉积中心,至晚期盆地中心北移,第三纪沉积中心则为平度蓼兰附近;盆地较深部位位于诸城凹陷、平度凹陷.胶莱盆地的次级构造单元可划分为11个,七级镇构造带控制了胶莱盆地的成生和发展.山东省岩浆岩通常表现为强磁性、低密度,但基性程度高的岩体磁性高、密度亦高,酸性程度高的岩体磁性低、密度低.     

BOOK REVIEWS

Book Reviewed in this article: The Vanishing Farmland Crisis, Critical Views of the Movement to Preserve Agricultural Land . John Baden Protecting Farmlands . Frederick R. Steiner and John E. Theilacker Ecological Effects of Fire in South African Ecosystems . Peter de V. Booysen and Neil M. Tainton Geography in China . Wu Chuanjun , Wang Nailiang , Lin Chao and Zhao Songqiao Resource Inventory and Baseline Study Methods for Developing Countries . Francis Conant , Peter Rogers , Marion Baumgardner , Cyrus Mc Kell , Raymond Dasmann, and Priscilla Reining Principles of Remote Sensing . Paul J. Curran Famine As A Geographical Phenomenon . Bruce Currey and Graeme Hugo The Suburban Squeeze: Land Conversion and Regulation in the San Francisco Bay Area . David E. Dowall Senses of Place . John Eyles Uneven Development and the Geographical Transfer of Value . D. K. Forbes and P. J. Rimmer Issues in Wilderness Management . Michael Frome Land-use and Prehistory in South-east Spain , The London Research Series in Geography 8. Antonio Gilman and John B. Thornes with Stephen Wise Regions in Question, Space, Development Theory and Regional Policy . Charles Gore The Colorado River: Instability and Basin Management . William L. Graf Hazardous Waste Sites: The Credibility Gap . Michael R. Greenberg and Richard F. Anderson Peasants, Subsistence Ecology, and Development in the Highlands of Papua New Guinea . Lawrence S. Grossman Silver Cities: The Photography of American Urbanization, 1839-1915 Peter B. Hales Silicon Landscapes . Peter Hall and Ann Markusen Remaking Ibieca: Rural Life in Aragon under Franco . Susan F. Harding The European Energy Challenge: East and West . George W. Hoffman The Global Climate . John T. Houghton The Urban Jobless in Eastern Africa . Abel G. M. Ishumi . The Tourist: Travel in Twentieth-Century North America . John A. Jakle City and Society: An Outline for Urban Geography . R. J. Johnston Residential Segregation, The State and Constitutional Conflict in American Urban Areas . R. J. Johnston Accessibility and Utilization: Geographical Perspectives on Health Care Delivery . Alun E. Joseph and David R. Phillips To the Heart of Asia: The Life of Sven Hedin . George Kish North American Culture , Vol 1. Ary J. Lamme III Past and Present in the Americas: A Compendium of Recent Studies . John Lynch Ethnicity in Contemporary America: A Geographical Appraisal . Jesse O. Mc Kee The Shell Countryside Book . Richard Muir and Eric Duffey 1990 Planning Conference Series. Proceedings of the National Geographic Areas Conference . Proceedings of the Regional Geographic Areas Conferences Wood, Brick, and Stone: The North American Settlement Landscape . Vol. 2: Barns and Farm Structures . Allen G. Noble Bangladesh: Biography of a Muslim Nation . Charles Peter O'donnell     

航空摄影测量应用中平坦地区高程精度的探索与实践

高程精度低的问题,一直是航空摄影测量产品的弱点,因此也是生产设计中的技术要点,本文通过三个实例,对不同资料、不同比例尺成果要求,采用不同技术措施保证了成果高程精度的做法进行了总结.     

数码航摄资料在数字化地形图测制中的应用

介绍从大比例尺地形图数码航测数字化成图存在的难点出发,综合生产实际,探讨全数字摄影测量内业作业过程各个环节的数学几何关系和误差影响,根据成图工艺流程和作业方法,研究对大此例尺数码摄影航测成图的地理精度和数学精度的质量控制,并对实践经验作了总结.     

海洋航空遥感多传感器应用系统集成

面向对象的程序设计思想和可视化编程技术使新技术的应用与推广变得越来越简单,在测绘和遥感等领域也已产生了前所未有的影响。在国家863计划项目航空遥感多传感器集成与应用技术系统(IAMSMA)的开发过程中,针对数据来源于多种传感器,充分利用数字图像处理的方法,采用模块化设计,将各传感器获取的数据与信息处理模块封装于统一的界面下,最终实现应用系统的集成。