利用Avenue程序快速加载ArcView主题图例方法的研究     

谢旭晖  周国清  臧德彦 《测绘科学》2008,33(3):169-171

利用ArcView系统自身提供的图例加载方法完成视图中主题图例的加载需要经过多个步骤。针对Arc-View系统以上繁琐的加载过程,本文探讨了一种更为有效的方法,即利用ArcView提供的二次开发环境——Avenue语言,通过编写Avenue程序代码,实现主题图例的快速加载。通过建立Avenue程序与图形用户界面(GUI)工具按钮的"链接",从而实现视图View中主题图例加载操作的简单化。  相似文献   

基于线性混合模型的端元提取方法综述   总被引：3，自引：1，他引：2  

陈子玄  武文波 《测绘科学》2008,(Z1)

混合像元是遥感领域研究的热点,而基于线性混合模型的光谱解混合技术正在越来越广泛地应用在光谱数据分析和遥感地物量化中,这项技术的关键就在于确定端元光谱。本文归纳了目前几种比较成熟的端元提取算法,分析了它们的主要思想和存在的优缺点,最后介绍了端元提取技术的应用及其发展趋势。  相似文献   

变形分析与预测模型中病态问题分析   总被引：1，自引：0，他引：1  

唐利民  朱建军  戴水财  王潜心 《测绘科学》2008,33(6):47-49

本文对变形分析与预测模型中的线性回归分析法、时间序列分析模型、灰色系统分析模型中的病态问题进行了理论分析和数值模拟。通过对变形观测资料施加干扰噪声,采用最小二乘原理,得出了三种模型中每一个参数与干扰噪声的数值关系表达式。指出在变形解释和变形预测中,用这三种模型进行建模分析时必须先检查信息矩阵A=XTX的病态程度,采取有效方法减轻A=XTX的病态程度后方可使用这三种模型。  相似文献   

地下水动态承载力与区域旱情监测预报研究     

张芹  孙振玉  孙红梅  宋庆健 《地下水》2008,30(3):1-3

对地下水动态承载力进行分析,并在区域旱情监测与预报中进行了理论和应用研究。先对地下水资源承载力建立了评价指标体系和相应的评分标准,再对旱情与承载力的关系从理论上进行了分析,利用大汶河流域地下水资源承载力的实例进行验证,得出了动态地下水承载力可以监测预报区域旱情的结论。提出可利用计算机程序进行动态承载力的计算,来监测和预报区域旱情的创新性结论。  相似文献   

ZG市非接触型诈骗被害相对发生概率的性别差异   总被引：4，自引：4，他引：0  

张春霞  柳林  周素红 《地理科学》2018,38(8):1218-1226

利用ZG市老城区2015~2016年具有个人属性的诈骗警情数据,分析女性和男性遭受非接触型诈骗相对接触型诈骗的发生概率,建立多层次Logit回归模型研究其影响因素的差异。结果表明,两性别非接触型诈骗被害的相对发生概率均受制于个体和社区两个层次因素的影响,且社区层次均发挥主要作用。其中,女性和男性在个体层次的影响因素类似,表现为本地户籍的高水平受教育者在白天更易遭受非接触型诈骗的侵害。但在社区层次的影响因素迥异,在外来人口少、银行网点少、离婚丧偶率低、有高校的本地年轻人为主的社区,女性非接触型诈骗被害相对发生概率高;而在租房比例高、农业人口少、大型零售商业网点少、低教育水平人口比例少的外来中高收入白领为主的社区,男性非接触型诈骗被害相对发生概率则更高。  相似文献   

MLR和PLSR的沙壤土盐分含量光谱检测对比研究          下载免费PDF全文

王涛  喻彩丽  姚娜  张楠楠  白铁成 《干旱区地理》2018,41(6):1295-1302

为了快速有效检测南疆地区典型土壤（沙壤土）的盐分含量变化,利用光谱仪和电导仪测得南疆阿拉尔市红枣种植区盐渍土近红外高光谱和电导率数据,基于7种不同光谱预处理方法和2种特征波长选择算法,分别建立多元线性回归（MLR）和偏最小二乘回归（PLSR）的土壤盐分监测模型。结果表明：7种预处理方法中,归一化,多元散射,变量标准化和一阶导数能够有效提高土壤盐分的预测模型精度。基于多元逐步回归（SMR）波长选择方法的多元线性回归（SMLR）模型的R_val²>0.948 9,RPD>6.294 9,RMSEP<0.435 6;基于连续投影算法（SPA）的多元线性回归（SPA-MLR）模型的R_val²>0.956 8,RPD>6.922 1,RMSEP<0.361 6,预测结果要优于偏最小二乘回归（PLSR）模型,其中基于归一化处理后的SMLR和SPA-MLR的预测精度最为理想,分别为R_val²=0.979 2,RPD=9.907 8,RMSEP=0.287 6和R_val²=0.980 5,RPD=10.50,RMSEP=0.278 3,而且筛选的特征波长较少。说明归一化是更有效的光谱预处理方法,多元线性回归（MLR）更适合建立南疆典型沙壤土盐分含量的预测模型。  相似文献   

A Geo‐spatial study for analysing temporal responses of NDVI to rainfall     

《Singapore journal of tropical geography》2018,39(1):107-116

Climate change has become a serious concern worldwide owing to its multifaceted impact upon the physical as well as socio‐economic environment (IPCC, 2013). Vulnerability to climate change is much higher in the developing countries like India, where the economy is mainly agro‐based and productivity from the agricultural sector is dependent upon summer monsoon rainfall. Hence, assessing the quantitative relationship between vegetation patterns and climatic influence has become an increasingly important study conducted on regional and global scales. As vegetation cover plays a key role in conserving the natural environment, studying the spatio‐temporal trend of vegetation is crucial in identifying changes in the natural environment. We analysed the spatial responses of SPOT‐VGT NDVI to TRMM based rainfall during a sixteen year period (1998–2013) in the Bundelkhand region of Central India. The Normalized Difference Vegetation Index (NDVI) has proven to be a strong indicator of global vegetation productivity. Among climatic factors, rainfall robustly influences both spatial and temporal outline of NDVI. In this study, we used linear regression for analysing the statistical relationship among NDVI and rainfall and their trends. The study reveals a varying pattern of vegetation dynamics in response to rainfall over the area.  相似文献   

SEISMIC MONITORING OF A BRIDGE: ASSESSING DYNAMIC CHARACTERISTICS FROM BOTH WEAK AND STRONG GROUND EXCITATIONS     

CHIN-HSIUNG LOH  ZHENG-KUAN LEE 《地震工程与结构动力学》1997,26(2):269-288

An array of 24 strong-motion accelerometers produced records for the New-Lian River Bridge, a five-span continuous bridge, during 25 February 1995 earthquake (weak motion) and 25 June 1995 earthquake (strong motion). This paper describes the application of linear discrete-time system identification methodology to the array of strong-motion measurements, in order to assess seismic response characteristics of the bridge. The structural system identification will concentrate not only on the global identification but also on the local structural system identification. Results of this application show that: (1) weak and strong ground excitation will induce significant differences on the dynamic response of the bridge; (2) linear models provide an excellent fit to the measured motions of the bridge from the records of these two seismic events; (3) the rigid-body rocking of the bridge pier during strong shaking is significant and cannot be ignored during identification; (4) the transverse motion at mid-span of the bridge is controlled by the quasi-static response from the boundary system and this phenomenon is quite significant during strong ground excitation. Also, systematic estimates of modal damping ratio and equivalent assessments of pier stiffness developed in the bridge during earthquake are discussed. © 1997 by John Wiley & Sons, Ltd.  相似文献   

利用ERDAS和MAPGIS进行点线类遥感信息的提取和符号化表示   总被引：1，自引：0，他引：1  

李远华  姜琦刚  张继承 《世界地质》2005,24(1):92-96

为在遥感解译过程中更好地将点线类遥感信息进行符号化表达、并准确地获取其各类属性值,本文结合遥感图像处理软件ERDAS与国产GIS软件MAPGIS的特点,分析了二者联合进行点线类遥感信息提取的可行性;制定一套利用二者进行点线类遥感信息提取的可行方案;并将其应用到地质灾害体的解译中;效果良好。充分利用二者的优点可进行点线类遥感信息的提取与符号化表示,可操作性较强。  相似文献   

SURFACE DISPLACEMENTS OF A NON-HOMOGENEOUS ELASTIC HALF-SPACE SUBJECTED TO UNIFORM SURFACE TRACTIONS. PART I: LOADING ON ARBITRARILY SHAPED AREAS     

R. F. Stark  J. R. Booker 《国际地质力学数值与分析法杂志》1997,21(6):361-378

A numerical technique is presented for the analysis of surface displacements of a non-homogeneous elastic half-space subjected to vertical and/or horizontal surface loads uniformly distributed over an arbitrarily shaped area. The non-homogeneity considered is a particular form of power variation of Young's modulus with depth. Since the exponent which determines the degree of non-homogeneity may vary from zero to unity, both the homogeneous half-space and the Gibson soil may be included as limiting cases in a single numerical scheme. In order to account for the arbitrary shape of the loading, the boundary of the loaded area is linearized piecemeal. This enables the modeling of any load pattern according to the desired degree of accuracy. Special attention is focused on the integration scheme, since the singularity associated with the Green's function becomes progressively more pronounced the greater the non-homogeneity parameter gets. The performance of the numerical procedure is studied using analytical solutions for rectangular shaped areas. Further comparisons with well-known solutions based on integral transform techniques for a uniformly distributed load acting on a circular area of the non-homogeneous soil mass show excellent agreement as well. © 1997 John Wiley & Sons, Ltd.  相似文献