基于高分卫星影像的复杂山区光伏电站信息提取          下载免费PDF全文

刘芸  宋善海  李慧璇  田鹏举  王伟 《中低纬山地气象》2023,47(3):76-80

该文基于高分卫星资料,通过基于规则的面向对象分类、基于最邻近法的监督分类及基于CART分类器的监督分类三种不同分类方法,对复杂山区光伏电站进行提取,对比三种分类提取方法结果并完成精度验证。结果表明,合理的分割参数有利于提高光伏电站提取精度;基于规则的面向对象分类法光伏电站提取精度最佳,最邻近分类法次之,CART分类器分类法最差,可利用基于规则的面向对象分类法较为准确地进行复杂山区光伏电站信息提取,为光伏产业健康、合理发展提供一定的数据支撑。  相似文献   

3种经典机器学习算法在火山岩测井岩性识别中的对比     

牟丹  张丽春  徐长玲 《吉林大学学报(地球科学版)》2021,51(3):951-956

岩性识别一直是火山岩油气勘探中的重要课题,基于测井数据的岩性识别也逐渐成为火山岩研究的需要,大数据背景下的机器学习算法为测井岩性识别提供了一个新方向。为提高某研究区火山岩岩性识别符合率,本文采用K近邻、支持向量机和自适应增强3种经典机器学习算法,对研究区内的粗面岩、非致密粗面岩、辉绿岩、辉长岩、玄武岩和非致密玄武岩等6类中基性火山岩进行岩性识别。从常规测井系列中优选对研究区岩性敏感的自然伽马、声波时差、补偿中子、深侧向电阻率和补偿密度等5种测井参数作为岩性识别模型的输入向量,从研究区内5口有岩心样品或薄片鉴定资料的目标层中选取测井数据点1 440个,其中960个作为训练样本,其余480个作为测试样本。以识别符合率和时间作为评价指标,对3种算法的识别结果进行对比分析,实验表明：自适应增强算法的分类准确率最高,6类岩性平均识别符合率达到82.10%;支持向量机算法表现良好,平均识别符合率为81.04%;K近邻算法平均识别符合率为76.04%。  相似文献   

美国内布拉斯加州林肯市犯罪行为的聚类及热点分布分析   总被引：1，自引：0，他引：1  

陈龙  Dr.Neil Stuart  Dr.Williams A.Mackaness 《测绘与空间地理信息》2015,(3):189-192

抢劫和入室盗窃犯罪行为是日常生活中最长见的违法行为,而这两种违法行为的发生有一定的规律可循。例如抢劫行为主要发生在市中心、CBD和商业中心的人群、商铺密集区域,而入室盗窃则多发生于生活社区及其周边地带。然而,想要防范这两种犯罪行为需要根据实际情况进行分析和比对,结合分析结果提出准确合理的警力部署。美国内布拉斯加州林肯市警察局针对该市抢劫和入室盗窃犯罪行为高发的情况,需要针对具体分析结果对于警力进行部署,主要针对徒步巡逻和是否需要对住户进行入户警示进行分析,根据分析结果进行具体部署。本文中使用的分析方法为紧邻层空间聚类分析(NNH)和针对犯罪的空间和时间分析法(SPAC),分别对林肯市入室行窃和抢劫的数据进行分析并尝试将两种方法进行对比以便给出更加科学的分析报告。  相似文献   

A novel method for discovering spatio-temporal clusters of different sizes,shapes, and densities in the presence of noise     

《International Journal of Digital Earth》2013,6(2):138-157

The discovery of spatio-temporal clusters in complex spatio-temporal data-sets has been a challenging issue in the domain of spatio-temporal data mining and knowledge discovery. In this paper, a novel spatio-temporal clustering method based on spatio-temporal shared nearest neighbors (STSNN) is proposed to detect spatio-temporal clusters of different sizes, shapes, and densities in spatio-temporal databases with a large amount of noise. The concepts of windowed distance and shared nearest neighbor are utilized to define a novel spatio-temporal density for a spatio-temporal entity with definite mathematical meanings. Then, the density-based clustering strategy is employed to uncover spatio-temporal clusters. The spatio-temporal clustering algorithm developed in this paper is easily implemented and less sensitive to density variation among spatio-temporal entities. Experiments are undertaken on several simulated data-sets to demonstrate the effectiveness and advantage of the STSNN algorithm. Also, the real-world applications on two seismic databases show that the STSNN algorithm has the ability to uncover foreshocks and aftershocks effectively.  相似文献   

Field survey and modelling of irrigation water quality indices in a Mediterranean island catchment: a comparison between spatial interpolation methods     

Nikolaos Malamos  Demetris Koutsoyiannis 《水文科学杂志》2013,58(10):1447-1467

ABSTRACT

A biannual survey of physico-chemical quality indices of 104 irrigation-water wells located in a cultivated plain of a Mediterranean island catchment was conducted using a multi-parameter probe. The campaign was planned so as to differentiate between the dry and wet seasons. The acquired data constituted the test bed for evaluating the results and the features of four spatial interpolation methods, i.e. ordinary kriging, universal kriging, inverse distance weighted and nearest neighbours, against those of the recently introduced bilinear surface smoothing (BSS). In several cases, BSS outperformed the other interpolation methods, especially during the two-fold cross-validation procedure. The study emphasizes the fact that both in situ measurements and good mathematical techniques for studying the spatial distribution of water quality indices are pivotal to agricultural practice management. In the specific case studied, the spatio-temporal variability of water quality parameters and the need for monitoring were evident, as low irrigation water quality was encountered throughout the study area.  相似文献   

Conditioning temperature‐index model parameters on synoptic weather types for glacier melt simulations          下载免费PDF全文

T. Matthews  R. Hodgkins  R. L. Wilby  S. Guðmundsson  F. Pálsson  H. Björnsson  S. Carr 《水文研究》2015,29(6):1027-1045

Temperature‐index models are widely favoured as a pragmatic means of simulating glacier melt because of their generally good performance, computational simplicity and limited demands for in situ data. However, their coefficients are normally treated as temporally stationary, unrealistically assuming a constancy of the prevailing weather. We address this simplification by prescribing model coefficients as a function of synoptic weather type, in a procedure that utilizes reanalysis data and preserves the minimal data requirements of temperature‐index models. Using a cross‐validation procedure at Vestari Hagafellsjökull, Iceland, and Storglaciären, Sweden, we demonstrate that applying transient model coefficients, for three temperature‐index models, results in statistically significant increases in the skill with which melt is modelled: Median simulation improvements in the Nash–Sutcliffe efficiency coefficient of 7.3 and 23.6% are achieved when hourly and daily melt totals are evaluated respectively. Our weather‐type modelling approach also yields insight to processes driving parameter variability, revealing dependence that is consistent with a priori considerations of the surface energy balance. We conclude that incorporating weather types into temperature‐index models holds promise for improving their performance, as well as enhancing understanding variability in coefficient values. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Simulating the membrane contact patterns of triaxial sand specimens     

D. R. Saussus  J. D. Frost 《国际地质力学数值与分析法杂志》2000,24(12):931-946

One of the common sources of error in triaxial tests is the penetration of the latex membrane into the peripheral voids of the specimen as confining pressure is applied. Existing analytical solutions developed to predict the magnitude of this membrane penetration have all assumed that the peripheral sand particles in contact with the surrounding membrane are arranged so that the centroids of the sand–membrane contact areas form a square pattern of side length D₅₀ on a plane parallel to the undeflected membrane. Measurements made on digital images of sand–membrane contact patterns for triaxial specimens of varying characteristics have shown this assumption to be inadequate. The analysis presented herein shows how actual contact pattern can be reasonably replicated by simulated patterns. These simulated patterns are generated by adding randomly selected distances to the centroid co‐ordinates of contact areas initially placed in a systematic grid pattern. The results indicate that it is possible to systematically model sand–membrane contact patterns as a function of triaxial specimen characteristics such as relative density and preparation method. The ability to simulate the real patterns eliminates the reliance of existing analytical solutions on a single assumed square contact pattern and hence can serve as the basis for improving the accuracy of future solutions to account for the effects of membrane penetration. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

一种分布式计算的空间离群点挖掘算法     

张卫平  刘纪平  仇阿根  张用川  赵阳阳 《测绘科学》2017,42(8)

针对现有空间离群点挖掘算法无法适应大规模空间数据挖掘的需求,该文提出了一种分布式条件下的空间离群点挖掘算法。首先,该文针对集群上分布式计算和存储的特点提出使用空间填充曲线来划分数据集,加速寻找目标点的近似空间最近邻居。其次,使用信息熵的理论来定义空间离群系数,考虑到多维数据中不同属性对离群系数的影响具有差异性,该算法能够自动根据数据原有特点,计算各属性的权重;同时使用反距离权定义空间因素对离群系数的影响。最后,实验结果表明该算法在大规模的空间数据集中挖掘离群点的效率远高于传统算法,离群点的挖掘精度在90%以上。  相似文献   

局部均值伪最近邻算法在降水预报中的应用     

林润生  黄明明 《沙漠与绿洲气象(新疆气象)》2017,11(5):1-8

分析北京地区日降雨量资料发现,相较于其他降雨事件,大雨或暴雨事件发生的次数较少,因此该地区的降水量预报属于样本不均衡问题。在样本不均衡的情况下,K最近邻算法的分类误差率将会大大提高,这也就使传统的基于K最近邻算法的降水量预报方法的应用受到了限制。针对北京地区降水量预报这一样本不均衡问题,应用局部均值伪最近邻算法构建了北京市的降水量预报模型。该方法利用北京地区日降雨量资料和美国国家环境预报中心全球格点资料,将降雨量作为类,将美国国家环境预报中心全球格点资料的各种因子场作为天气样本特征,计算得到不同天气样本在所有类中的局部均值伪最近邻,通过决策规则实现最优分类。利用提出的降水预报模型对北京市2010年6—8月进行了24 h降水预报,实验结果表明,提出的预报方法对于降水等级预报的预报准确率以及晴雨预报的TS评分、正样本概括率、空报率和漏报率均优于传统的K最近邻预报方法,该方法具有较好的预报效果。  相似文献   

福建省旅游小镇空间分布特征及影响因素研究     

林秀治  陈秋华 《地理科学》2021,41(9):1645-1653

以福建省155个旅游小镇为研究样本,运用空间统计分析法对其空间分布特征及影响因素进行研究。结果表明：① 福建省旅游小镇空间分布整体上趋于均匀状态,在各个地市的数量分布上也相对均衡;② 福建省旅游小镇核密度呈现出“东高、西低”的分布特征,生态人居型旅游小镇分布密度最大,特色产业型旅游小镇分布密度最小;③ 福建省旅游小镇发展以冷点区和次冷点区为主,冷点区和热点区空间差异明显;④ 经济基础、城镇化水平、人口密度、客源市场是福建省旅游小镇空间分布的主要影响因素。  相似文献