Terrain Pattern Recognition and Spatial Decision Making for Regional Slope Stability Studies   总被引：1，自引：0，他引：1  

George?MiliaresisEmail author  Nikos?Sabatakakis  George?Koukis 《Natural Resources Research》2005,14(2):91-100

A terrain partition scheme is presented that allows the identification of regions with high landslide risk in natural terrain zones on the basis of geomorphometric criteria from moderate resolution DEMs. The key factor being the terrain segmentation to aspect regions (regions formed by points preserving the same aspect direction) instead of using an artificial regular-grid terrain partition scheme. The study area is in western Greece (NW Peloponnesus) whereas a moderate resolution digital elevation model with spacing 75 m is used. Landslide inventory analysis and knowledge conceptualization identified that the landslide susceptibility of a particular aspect region is high, if the mean elevation is low and the mean gradient is high. Each aspect region was parametrically represented on the basis of its mean gradient and elevation. The domain of each parameter was divided to seven slices (classes) on the basis of the observed density. Subsequent knowledge based mapping identified aspect regions with high landslide susceptibility for the following spatial rule: (a) “mean slope in class 6 or 7” and (b) “mean elevation in class 1 to 5”. Alternatively the rule is expressed as mean slope to be equal or greater than 15^∘ whereas mean elevation to be in the range 0 to 750 m. These identified zones correspond to regions where historical landslides occurred (populated coastal areas in the North) as well as to south regions (natural terrain zone) where no landslide record is available, because of the limitations posed by the natural terrain landslide mapping program in Greece. The presented terrain segmentation technique combined to the spatial decision-making process, provided both an object framework for integrating geomorphometric parameters and a method for landslide risk analysis in natural terrain zones.  相似文献   

太行山前平原非河道条件下地下调蓄功能实验研究--以滹沱河冲洪积平原为例   总被引：5，自引：0，他引：5  

张光辉费宇红  邢开刘克岩  王金哲申建梅 聂振龙 《水文》2004,24(2):15-19

摘要：通过实验研究探讨了太行山前平原地下调蓄能力,实验研究表明,在汇水坑渗、井灌和引水渠渗条件下,太行山前冲洪积平原地下调蓄功能不仅与地表积水深度、入渗时间有关,而且还与汇水总量的多少有关。单位时间渗漏量的大小与地表蓄水深度呈正相关关系。地表蓄水深度愈大,单位时间渗漏量愈大;累计渗漏量随着入渗时间的延长而增加,渗漏速率随着累计渗漏量的增加而减小。采用井灌方式进行地下调蓄的关键,是选择具有强渗透性的层位。  相似文献   

3维地理信息系统技术综述   总被引：23，自引：1，他引：22  

朱庆 《地理信息世界》2004,2(3):8-12

文中对3维地理信息系统技术进行综述性介绍,扼要地讨论了国内外有关3维地球空间信息的获取、管理、分析与可视化等技术的进展与动态,并分别探讨了它们的优势和局限。  相似文献   

花海盆地深地震反射剖面的最佳采集参数实验和分析          下载免费PDF全文

王冠  熊小松  高锐  陈宣华 《中国地质》2019,46(5):1146-1160

深地震反射方法是探测地壳深部结构的先锋技术,能获取到莫霍面和上地幔的反射图像,成为揭示岩石圈结构、解决深部地质构造问题的有效手段。花海盆地位于河西走廊盆地群西部,处于不同大地构造单元的交汇部位,地层发育较全,但出露和发育程度差异较大,除白垩系为大面积连续分布外,其他各时代的地层均出露不全,常表现为被侵入岩分割破坏的残块状,为了确定深地震反射在花海盆地适合的采集参数,在采集前开展点试验,进行小、中、大炮炸药井炮激发参数对比优选,最终得到最优化的采集参数。在小炮实验中,36 kg药量取得的反射信息没有48 kg和60 kg的丰富,而且在MOHO反射的清晰度上48 kg和60 kg药量更为清晰,单井激发比组合井激发效果好;在中炮和大炮实验中,不同组合井对比差异不大,随着药量增大,激发能量增大,面波、折射波等干扰波能量也在增大,小炮干扰波能量最弱,反射信息最丰富的,中炮和大炮干扰波较发育,但通过后期去噪处理,也能得到中浅层反射信息。  相似文献   

离心模型试验中微型土压力盒土压力测定   总被引：1，自引：0，他引：1  

梁波  厉彦君  凌学鹏  赵宁雨  张青松 《岩土力学》2019,40(2):818-826

土压力作为离心模型试验中重要的测试参数,受土压力盒的性能、离心机数据采集系统稳定性及外部环境等诸多因素的影响,准确地测量土压力较为困难。土压力盒作为土压力测试元件,其性能对土压力测量准确性有直接影响。为获得较为准确的土压力测试数据,结合离心机数据采集系统,选择两种常见的电阻应变式土压力盒。通过标定试验得出两种土压力盒砂标系数均小于出厂标定系数,Ⅰ型偏小64.75%,Ⅱ型偏小18.77%,Ⅱ型土压力盒与出厂数据的重合度比Ⅰ型好;在研究墙高10～30 m类扶壁式挡墙侧向土压力分布的离心模型试验中,与Ⅱ型土压力盒相比,Ⅰ型存在按出厂系数测得数据失真、灵敏度低和稳定性差的缺点。标定试验和离心试验结果表明,接入自行组建的数据采集系统的Ⅱ型土压力盒比接入静态应变数据采集系统的Ⅰ型土压力盒性能更佳。  相似文献   

Impact of fractional probability distributions on statistics of hydraulic conductivity,dynamics of groundwater flow and solute transport at a low-permeability site     

Chengpeng Lu  Wei Qin  Ching-Sheng Huang  Yong Zhang  Tema Koketso Ealotswe 《水文研究》2020,34(21):4112-4127

The fractional Brownian motion (fBm) and fractional Lévy motion (fLm) can easily describe the geometry and the statistical structure of hydraulic conductivity (K) for real-world. However, the fBm and fLm models have not been systematically evaluated when building the K field for a low-permeability site. In this study, both the fBm and fLm are used to simulate the low-K field at NingCheGu (NCG), Tianjin, China. Groundwater flow and solute transport are then computed using MODFLOW and MT3DMS, respectively, and the influence of the fBm/fLm models for K on groundwater flow and solute transport is discussed. Results show that the fLm fits better the statistics of the low-K medium than fBm, and the random logarithmic K (LnK) field generated by fLm is more stable because the resultant LnK field captures more of the measured properties at the field site than that generated by fBm. In contrast, the LnK generated by fBm is more likely to form both high-K channels and low-K barriers. The fBm therefore predicts more extreme behaviours in flow and transport, including the preferential flow, low-concentration blocks and solute retention. The overall groundwater renewal period and solute travel time for the fLm simulation are slightly shorter than those for fBm. The impacts of the fLm and fBm models on the statistics of the resultant LnK fields and the dynamics of groundwater flow and solute transport revealed by this study shed light on the selection and evaluation of the fractional probability distribution models in capturing the K fields for low-K media.  相似文献   

老挝北部Sentinel-2 A/B云覆盖适宜阈值界定及其影像获取概率时空差异     

刘怡媛  李鹏  肖池伟  刘影  谢正磊 《地球信息科学学报》2020,22(11):2267-2276

光学卫星影像云覆盖时空特征评估是衡量其作为重要遥感监测数据源的前提。Sentinel-2 A/B影像因其免费获取、多光谱（红边）、更高时空分辨率等优势,已在全球不同尺度陆面植被与生态监测中受到重视。相较于Landsat等同类影像产品,有关Sentinel-2 A/B的云覆盖分析还未见报道。本文利用2016—2018年老挝北部所有5288景Sentinel-2 A/B影像（Granule/Tile）的云覆盖元数据,基于不同云覆盖阈值（0~100%）水平下的影像获取概率差异确定了影像获取概率分析的云覆盖适宜阈值,并揭示了云量特征阈值水平下的影像获取概率时空差异。主要结论如下:① Sentinel-2 A/B影像获取概率分析云覆盖适宜特征阈值为20%（即云覆盖≤20%）,该阈值水平下老挝北部Sentinel-2 A/B影像的逐月累积平均获取概率最高（约27.41%）;② 在20%云覆盖阈值水平下,老挝北部Sentinel-2 A/B影像逐月累积平均获取概率差异在时间上与旱季（11月—次年4月）雨季（5月—10月）的时间分布较为吻合。旱季获取概率约为42.91%,3月概率（50.27%）最大,4月与2月次之,时间上与刀耕火种焚烧与橡胶林落叶特征吻合;雨季相应概率约为11.81%,6月最低（约1.26%）;③ 老挝北部Sentinel-2 A/B影像逐月累积平均获取概率在空间上存在东西差异,旱季西部省域单元（如琅南塔）影像获取概率远高于东部,雨季西部地区影像获取概率则略低于东部地区。本研究既可为后续开展大区及全球Sentinel-2 A/B影像云量分析提供借鉴,也对开展联合国减少森林砍伐和退化排放（UN-REDD）计划引发的土地利用变化如刀耕火种农业演变、橡胶林扩张等遥感监测有指导意义。  相似文献   

航测立体采集在水库河流测量中的应用     

孙悦 《测绘与空间地理信息》2017,(4)

自古以来,水库和河流等水利工程就是一件关系着国计民生的大事。水库的库容及水库的调度,河流的河道情况,关系到防洪安全、水库区及河流两岸居民的居住环境的变化和蓄水兴利。本文介绍了大中型水库库区范围内,以及沿河两岸地物、地貌的航空摄影的内业采集及采集过程中所遇到的困难以及解决办法。  相似文献   

圆周移位在伪码补零BDS信号捕获算法中的应用     

张利伟  赵冬青  彭少磊 《测绘科学技术学报》2017,(5):466-469

D1导航电文中加入了NH码,且D2导航电文的速率也比GPS信号的快很多,使得BDS的信号结构增加了捕获难度。采用伪码补零的方法可以对BDS信号进行有效捕获,但是该方法积分时间较长导致捕获耗时变长。本文提出了一种基于圆周移位的改进伪码补零算法,将搜索中复杂的载波剥离运算用计算量很小的频谱序列的搬移操作来代替,使算法复杂度大幅下降。试验结果表明,该方法可以有效减少运算量和捕获耗时。  相似文献   

Bringing globalization to the countryside: Special Economic Zones in India          下载免费PDF全文

Mohammad Amir Anwar  Pádraig Carmody 《Singapore journal of tropical geography》2016,37(2):121-138

Special Economic Zones (SEZs) are important vectors of neoliberal globalization in India. Despite facing widespread resistance against the proposed land acquisition for these zones, they are still being promoted across the country. We argue that the wealth redistribution to the country's elites and the fractured resistance movements enable neoliberalism and its practices to grow in the countryside. Using a private sector SEZ in Gurgaon as a case study, this article explores how special economic zoning, as a neoliberal policy, has been implicated in the spatialized production of poverty. We also show that the main actors who promote neoliberalism in India (the state and the large‐scale urban private sector) have found a seemingly unlikely ally in rural India in the form of farmers with large landholdings, rural elites who are willing to let go of their land under certain conditions. The data for the article was collected in India in 2009–10.  相似文献