Quality assessment in point feature generalization with pattern preserved          下载免费PDF全文

Wenhao Yu 《Transactions in GIS》2018,22(3):872-888

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三维地理景观多方位一体化表达技术研究     

霍亮  朱王璋  杨耀东  乔文昊 《测绘科学技术学报》2013,30(1):6-9

针对三维可视化技术在地理景观表达中的应用现状,设计了一种基于二维、三维及360°全景技术的地理景观多方位可视化方案,探讨了三维地理景观多方位一体化表达系统的构建流程以及关键技术;并结合传统制图、三维建模、360°全景、Html等技术,采用地貌晕渲图、三维场景和360°全景实时联动的方式构建了三维地理景观多方位一体化表达系统,实现了对三维地理景观的多方位可视化与空间分析,在实际应用过程中取得了较好效果。  相似文献   

汶川Mw7.9地震余震序列触发机制研究     

申文豪  刘博研  史保平 《地震学报》2013,35(4)

余震触发机制的Dieterich解析模型被广泛应用于区域地震活动性的定量分析以及依赖时间的概率地震预测模型的建立等方面.基于滑移速率和状态相依赖的摩擦定律和弹簧-滑块模型,从Dieterich断层滑移速率方程出发,给出了静态应力扰动下触发地震的时钟提前或推后的近似解,从而明确地阐明了触发地震的产生机制与断层的演化过程密切相关,并与传统位错模型下库仑应力扰动时间提前或推后量作了比较.采用对数线性拟合方法求得了汶川Mw7.9主震后余震序列持续时间,符合Dieterich理论结果.以汶川余震序列为例,给出了两种不同的应力扰动模式在该余震序列中的应用.结果表明,经典Dieterich扰动解无法给出主震发生后即时余震数量的异常增加,而考虑主震前后剪应力速率变化的Dieterich分段解则可反映出余震发生率及个数随时间的演化特征.  相似文献   

Synthetic seismic intensity for historic earthquakes in the North China Plain: implications for the regional seismic hazard     

Wenhao Shen  Qiu Zhong  Baoping Shi 《Natural Hazards》2014,74(2):305-323

Multiple approaches are used to study the potential seismic hazard in the North China Craton (NCC, or North China Plain), where approximately 15 % of the Chinese population resides and under which active faults are located. In this study, we develop a new modified Mercalli intensity (MMI) attenuation relationship for the NCC using intensity data from 10 instrumentally recorded events. We then utilize this relationship to infer the magnitude and epicentral location of historic events based on the method proposed by Bakun and Wentworth (Bull Seismol Soc Am 87(6):1502–1521, 1997). In addition, a modified stochastic finite fault model is employed to simulate the strong ground motions caused by these historic events. The simulated peak ground accelerations and velocities are then converted into regional MMI distributions through empirical relationships, and these synthetic MMI maps are compared to field observations. The resultant MMI attenuation versus distance models of the 1976 M _w 7.6 Tangshan event and the 1679 M 8.0 Sanhe-Pinggu event are consistent with the empirical attenuation relationships, and the location and size of the meizoseismal area (>VIII) are consistent with observations. The successful modeling of these historic events indicates that a stochastic finite fault model constrained by the regional MMI attenuation relationship can be used to evaluate a wide range of scenarios based on modern computational simulations. These findings may also provide useful information for the estimation and mitigation of potential seismic hazards in this region.  相似文献   

极区海冰影像自动监测系统的设计与试验     

常晓敏  李文龙  刘大雷  刘文浩  左广宇  窦银科 《极地研究》2022,34(2):210-218

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A preliminary methods comparison for measurement of dissolved organic nitrogen in seawater   总被引：2，自引：0，他引：2  

Jonathan H. Sharp  Kathrine R. Rinker  Karen B. Savidge  Jeffrey Abell  Jean Yves Benaim  Deborah Bronk  David J. Burdige  Gustave Cauwet  Wenhao Chen  Marylo D. Doval  Dennis Hansell  Charles Hopkinson  Gerhard Kattner  Nancy Kaumeyer  Karen J. McGlathery  Jeffrey Merriam  Nick Morley  Klaus Nagel  Hiroshi Ogawa  Carol Pollard  Mireille Pujo-Pay  Patrick Raimbault  Raymond Sambrotto  Sybil Seitzinger  Georgina Spyres  Frank Tirendi  Ted W. Walsh  C. S. Wong 《Marine Chemistry》2002,78(4)

Routine determination of dissolved organic nitrogen (DON) is performed in numerous laboratories around the world using one of three families of methods: UV oxidation (UV), persulfate oxidation (PO), or high temperature combustion (HTC). Essentially all routine methods measure total dissolved nitrogen (TDN) and calculate DON by subtracting the dissolved inorganic nitrogen (DIN). While there is currently no strong suggestion that any of these methods is inadequate, there are continuing suspicions of slight inaccuracy by UV methods.This is a report of a broad community methods comparison where 29 sets (7 UV, 13 PO, and 9 HTC) of TDN analyses were performed on five samples with varying TDN and DIN concentrations. Analyses were done in a “blind” procedure with results sent to the first author. With editing out one set of extreme outliers (representing 5 out of 145 ampoules analyzed), the community comparability for analyzing the TDN samples was in the 8–28% range (coefficient of variation representing one standard deviation for the five individual samples by 28 analyses). When DIN concentrations were subtracted uniformly (single DIN value for each sample), the comparability was obviously worse (19–46% cv). This comparison represents a larger and more diverse set of analyses, but the overall comparability is only marginally better than that of the Seattle workshop of a decade ago. Grouping methods, little difference was seen other than inconclusive evidence that the UV methods gave TDN values for several of the samples higher than HTC methods. Since there was much scatter for each of the groups of methods and for all analyses when grouped, it is thought that more uniformity in procedures is probably needed. An important unplanned observation is that variability in DIN analyses (used in determining the final analyte in most UV and PO methods) is essentially as large as the variability in the TDN analyses.This exercise should not be viewed as a qualification exercise for the analysts, but should instead be considered a broad preliminary test of the comparison of the families of methods being used in various laboratories around the world. Based on many independent analyses here, none of the routinely used methods appears to be grossly inaccurate, thus, most routine TDN analyses being reported in the literature are apparently accurate. However, it is not reassuring that the ability of the international community to determine DON in deep oceanic waters continues to be poor. It is suggested that as an outgrowth of this paper, analysts using UV and PO methods experiment and look more carefully at the completeness of DIN conversion to the final analyte and also at the accuracy of their analysis of the final analyte. HTC methods appear to be relatively easy and convenient and have potential for routine adoption. Several of the authors of this paper are currently working together on an interlaboratory comparison on HTC methodology.  相似文献   

多源遥感图像的1976年Ms7.8唐山大地震等烈度区判定     

张景发  李强  张庆云  田甜  申文豪  薛腾飞  王建飞 《遥感学报》2018,22(S1):162-173

传统的地震烈度评估方法依靠人为实地调查,易造成部分地区数据缺失,导致等烈度线丢失细节信息。本文以实地调查的等烈度线分布为基准,结合保存的唐山地震震后航片资料、卫星图像和其他资料,从宏观上更细致地开展了唐山地震的等烈度线图判定研究。首先,利用地震后的航空照片和地震前美国锁眼（KH）卫星图像进行对比分析,详细判读典型震害建构筑物目标、喷砂冒水等,总结影像判读标准,采用面向对象分类变化检测的方法确定极震区和重点破坏区分布;然后,利用地震前后的航片、KH卫星、美国陆地资源卫星Mss图像,选取2495个建筑区样本点,基于图像纹理信息熵的相关性分析对重点村镇目标进行变化检测处理,确定各村镇建筑物的破坏程度及其趋势;最后,综合分析历史航片、余震等资料,分析地震发震断层等多源遥感资料,基于反距离加权插值的方法对样本点进行插值获取地震烈度分布区域,综合多源遥感资料实现了唐山地震的地震烈度区的判读,与前人实地调查结果对比,综合多源遥感图像判定的地震烈度区与实地调查结果形态相近,证明该方法可用于地震烈度评估。  相似文献   

Methods for industrial measurement and basic principles of their choices     

Feng Wenhao 《地球空间信息科学学报》2013,16(2):28-36

In this paper, a variety of industrial objects are systematically analyzed. Ten methods for industrial measurement are summarized. For each method, its nature, advantages, disadvantages and adaptability are briefly given. The basic principles to choose the right industrial method are indicated.  相似文献   

The formation environment and development modes of Cenozoic source rocks in the Qiongdongnan Basin     

Wenhao Li  Zhihuan Zhang  Youchuan Li  Ning Fu  Yanran Huang  Ling Zan  Huimin Zhang 《中国地球化学学报》2012,31(4):431-440

According to the drilling results,there are three sets of source rocks of the Cenozoic Group in the Qiongdongnan Basin,including the Yacheng Formation transitional facies mudstone,the Oligocene Lingshui Formation semi-enclosed marine facies mudstone,and the Miocene neritic-bathyal facies mudstone.The hydrocarbon generating conditions of the source rocks in the study area are mainly controlled by sedimentary environment and organic matter input.The abundance of organic matter in the Oligocene source rocks which were formed in a low-energy back shore environment is confined by organic matter input and hydrodynamic condition.The Miocene source rocks formed in the open marine environment lack terrestrial organic matter input,whose organic matter abundance is constrained by the primary production of the ocean and the preservation condition of organic matter.In addition,the redox conditions are also significant to the formation of source rocks in the study area.According to the differences in key factors controlling the development of source rocks in different time periods and structural belts revealed by drilling practice,three development patterns of source rocks have been put forward.The first one is the transitional facies model featuring a great deal of terrestrial organic matter and weakly hydrodynamic conditions which are apt to develop high effective source rocks in the Yacheng Formation.The second one is the semi-enclosed marine facies featuring abundant terrestrial organic matter,weakly hydrodynamic condition and fine preservation condition in the central depression zone,which are apt to form fine-quality source rocks in the Lingshui Formation.The third one is the marine facies model featuring strong hydrodynamics in the shore-shallow area of northern continental shelf and the lack of benthic algae which are against the development of source rocks.It can be predicted that the continental slope is the perfect place to form source rocks where adequate amounts of light favor the photosynthesis of plants,besides the fine preservation and weakly hydrodynamic conditions.In the deep sea area,although accompanied with weakly hydrodynamic conditions and a reduction environment,it is not suitable for the development of source rocks on account of less aquatic organisms causing low primary production.  相似文献   

MESOZOIC AND CENOZOIC UPLIFT-DENUDATION ALONG THE ALTYN TAGH FAULT,NORTHWESTERN CHINA: CONSTRAINTS FROM APATITE FISSION TRACK DATA   总被引：1，自引：0，他引：1  

Zhang Zhicheng  Guo Zhaojie  Li Jianfeng  Tang Wenhao 《第四纪研究》2012,32(3)

本文利用裂变径迹方法探讨阿尔金断裂中段吐拉-肃北之间隆升和剥露过程.古生代花岗岩和侏罗系沉积岩的磷灰石裂变径迹年龄介于107.2 ±9.0Ma到14.1±1.3Ma之间,明显小于其侵位年龄或者沉积年龄.自西部的吐拉到东端的肃北,磷灰石裂变径迹年龄逐渐升高,从14.1±1.3Ma增加到107.2±9.0Ma.花岗岩和侏罗系砂岩的磷灰石裂变径迹模拟结果表明,阿尔金断裂南侧地质体经历了两阶段的快速冷却过程,早期为33Ma左右,晚期为8Ma左右;阿尔金断裂北侧经历了晚白垩世开始的相对缓慢的冷却过程以及8Ma以来快速冷却事件.阿尔金断裂南北两侧的地质体的裂变径迹年龄和热历史略有差异,可能反映阿尔金断裂的影响.33Ma左右的快速冷却事件可能是阿尔金断裂活动引起的快速去顶作用的开始,这一事件对应了印度和欧亚板块碰撞.8Ma左右的冷却事件,与阿尔金山地区盆地内的快速沉积过程相一致,同时可能是青藏高原抬升与侧向生长在本区的响应.  相似文献