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利用地面三维激光扫描技术快速、远距离获取人员无法到达的复杂山丘区的高分辨率、高精度的点云数据的优势,提出了将地面三维激光扫描技术应用于山洪灾害调查评价工作的技术路线和解决方案。以云南轿子山小流域的山洪灾害调查评价应用为例,详细论述了地面激光扫描技术快速高效获取小流域及沿河村落的激光点云数据、基于多尺度维度特征的激光点云数据分类、断面数据获取、高精度DEM制作以及地形图制作等方法,编制了应用于山洪灾害现场调查的专用激光点云数据处理软件。案例应用表明,地面三维激光扫描技术获取数据速度快、精度高,为无资料地区山洪灾害分析评价提供了高精度数据支撑,能够满足山洪灾害调查评价的工作要求,该技术在即将开展的全国山洪灾害调查评价工作中将发挥巨大作用,具有较大的应用前景。 相似文献
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利用三维激光扫描测量技术的快速高精度高密度获取测量对象的三维点云数据特点,分析探索其运用于大坝变形监测的方法。该方法改变了传统以变形点代替整个大坝外部变形的分析方式,更能快速时时获取真实反应大坝变形的数字地面模型数据。体现出其在大坝监测中的明显优势。 相似文献
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TLS在建立高精度DEM中的应用 总被引:1,自引:0,他引:1
介绍了高精度DEM数据采集的新技术。应用地面三维激光扫描Terrestrial Laserscanning(TLS)系统对小流域进行扫描获取点云数据,经分析处理生成高精度DEM,并对拼接误差进行评价。实践表明,三维激光扫描系统适用于小流域高精度DEM数据采集。 相似文献
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为解决利用机载激光测深(Airborne LiDAR bathymetry, ALB)波形数据估计水体含沙量(Suspended Sediment Concentration, SSC)难题,提出了一种利用ALB三维点云数据反演水体含沙量的新方法。首先,基于绿激光水面点和红外激光水面点计算绿激光水面穿透量;其次,利用实测水体含沙量及对应绿激光水面穿透量构建SSC经验模型;最后,基于构建的SSC经验模型实现了利用ALB三维点云的水体含沙量估计。实验验证了该方法的有效性,取得了优于20 mg/L的SSC反演精度,为水体含沙量信息的高精度、大区域面获取提供了一种新途径。 相似文献
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利用三维激光扫描技术获取三星堆月亮湾城墙遗址区高精度三维激光点云,实现了任意边界挖填方量的精确计算。采用IDL编制了海量激光点云存储与管理软件LIDARVIEW,应用海量激光点云网格分块技术和动态四叉树空间索引方法实现了海量激光点云数据的存储与管理。提出基于网格分块的地表植被和建筑物的自动过滤技术,建立三星堆月亮湾城墙遗址现状地表的DEM模型。结合三星堆月亮湾城墙遗址的覆土设计方案,得到月亮湾城墙遗址覆土后地表DEM数据和覆土四周边界数据。最后利用覆土前后地表的DEM数据,对三星堆月亮湾城墙遗址覆土方量进行计算。工程实例表明,该方法可以快速、高效地解决复杂工程的挖填方的方量计算。 相似文献
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机载Li DAR作为一种新型的对地观测技术,由于具有主动性、受天气影响小、不受阴影影响以及对地物间缝隙具有一定的穿透性等特点,目前备受应用者和研究者的广泛关注。它能直接获取高精度的地表三维点云数据(DSM),为等高线的提取提供了新的契机。由于等高线不能穿过房屋及水系区域,传统方法需要采用人工后处理的方法实现等高线在这些区域的编辑和处理,耗时耗力。因此,提出一种基于特征约束Li DAR点云数据等高线提取方法,该方法主要包括3个方面:1点云数据的滤波生成DEM点云数据,为等高线的生成提供基础数据;2基于Li DAR点云数据的特征提取,包括水系、房屋等特征;3在特征提取的基础上,实现基于特征约束的TIN三角网的自动生成,并在此基础上,利用张力样条函数法实现高精度提取。较传统摄影测量立体像对方法,此方法具有可靠性高、效率快、作业精度高的特点。 相似文献
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本文通过基于球面投影大坝三维表面构建算法构建土石坝表面模型,重建土石坝精确三维表面模型,将第一期数据作为参考数据,利用不同时期采集的点云数据与参考模型进行对比分析来获取大坝变形信息。通过试验验证了本文方法的可行性和实用性。 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献