胶东半岛果园TM影像信息的提取决策树方法   总被引：2，自引：0，他引：2  

于新洋  张安定  侯西勇 《测绘科学》2012,(4):57-60

本文选取胶东半岛最具代表性的5个果品县(市)为研究区,以Landsat TM影像数据为分类影像,尝试提取果园信息。选用可以"无缝"融入多种辅助信息的决策树分类方法,综合NDVI、地形地貌和缨帽变换等多种辅助信息,利用年内物候变化最大的果园与背景地物的光谱差异,进行果园信息提取;利用SPOT影像以及野外考察资料作为检验样本进行精度验证。表明综合多种辅助信息,利用决策树分类法提取TM影像果园信息可行且准确性较高。  相似文献   

最大空圆约束下的最邻近计算方法     

闫超德  郭王  白建军  贺添  赵姗 《测绘科学》2012,37(6):157-159

移动目标的最邻近查询是位置服务的重要内容之一。本文针对地理目标分布不均的情况,将离散点集的最大空圆参数引入到最邻近查询中,提出了最大空圆约束下的k-D树最邻近查询算法。通过实验证明该算法可以有效地减少节点访问次数,减少距离计算次数,从而提高最邻近的查询效率。进而将该算法应用于移动目标的k阶邻近查询中,可以有效地减少移动点在三角网中的定位次数,改善k阶邻近的查询效率。  相似文献   

利用特征选择自适应决策树的层次SAR图像分类     

何楚  刘明  许连玉  刘龙珠 《武汉大学学报(信息科学版)》2012,37(1):46-49

提出了一种新的基于特征选择自适应决策树的层次分类算法,用于合成孔径雷达（synthetic apertureradar,SAR）图像的分类。采用Joint Boosting算法选择出最适用于各类的特征组合,并自适应地搜索构造出一个由两类分类器构成的层次分类器,利用特征选择结果和自适应决策树进行了SAR图像的学习和推理,实现了自动分类,在国内首批极化干涉SAR数据上的实验证明了本算法的有效性。  相似文献   

面向智能移动设备的GIS服务     

耿晴  范伟  孙续锦  刘平 《地理空间信息》2012,(3):64-66,69

随着嵌入式技术的发展,智能移动设备正成为无线接入的重要方式。通过智能移动设备来提供GIS服务是亟待解决的关键问题。分析了智能移动设备的特点,总结了其发展趋势;设计了面向智能移动设备的GIS服务体系,并对其结构进行了阐述。  相似文献   

ID3决策树推理模型及其在道路网选取中的应用     

郭敏  钱海忠  黄智深  刘海龙  鞠金春 《测绘科学技术学报》2012,(4):308-312

介绍了自动制图综合中知识推理的研究现状及存在的问题,指出了借鉴人工智能优秀技术成果提升自动综合智能化水平是解决当前问题的重要途径之一。对ID3智能算法的基本原理进行了详细介绍,提出基于ID3决策树的知识推理模型。将该模型引入到道路网智能化选取当中。对该模型应用到道路网自动选取的合理性进行了论述,并进行了实验验证。在对实验结果进行详细分析的基础上,探讨了该算法应用于道路网选取的优势和不足,指出了进一步研究的方向。  相似文献   

混合式球面退化剖分模型的设计与编码     

李正国  包全福  张永生  靳彩娇 《测绘科学技术学报》2012,(4):289-293

为了解决球面退化四叉树格网(DQG)模型孔径较大、格网单元面积分布不均匀以及三角格网单元应用不完全四叉树剖分的问题,通过控制单元面积的思路设计了一种格网单元孔径更小、分布更均匀的四边形(中低纬地区)与三角形(高纬地区)的混合格网模型——混合式球面退化格网模型(MSDG);并对所有格网单元利用四叉树进行编码。通过对格网单元的几何属性统计分析发现,该格网模型的几何属性与DQG模型相比,其单元面积变化更小、分布更加均匀稳定。  相似文献   

A Sustainability Initiative to Quantify Carbon Sequestration by Campus Trees     

《The Journal of geography》2012,111(5):173-183

Abstract

Over 3,900 trees on a university campus were inventoried by an instructor-led team of geography undergraduates in order to quantify the carbon sequestration associated with biomass growth. The setting of the project is described, together with its logistics, methodology, outcomes, and benefits. This hands-on project provided a team of students with several learning opportunities including an introduction to carbon sequestration, basic arboriculture, field-based measurements, mapping, geographic information systems, and biogeography concepts. A GIS geodatabase was produced containing information on tree location, species, size, biomass, carbon content, and annual CO₂ sequestration, which was later customized for integration into campus facilities management.  相似文献   

Mapping rubber tree growth in mainland Southeast Asia using time-series MODIS 250 m NDVI and statistical data   总被引：5，自引：0，他引：5  

Zhe Li  Jefferson M. Fox 《Applied geography (Sevenoaks, England)》2012,32(2):420-432

Expanding global and regional markets are driving the conversion of traditional subsistence agricultural and occupied non-agricultural lands to commercial-agricultural purposes. In many parts of mainland Southeast Asia rubber plantations are expanding rapidly into areas where the crop was not historically found. Over the last several decades more than one million hectares of land have been converted to rubber trees in areas of China, Laos, Thailand, Vietnam, Cambodia and Myanmar, where rubber trees were not traditionally grown. This expansion of rubber plantations has replaced ecologically important secondary forests and traditionally managed swidden fields and influenced local energy, water and carbon fluxes. Accurate and up-to-date monitoring and mapping of rubber tree growth is critical to understanding the implications of this changing ecosystem. Discriminating rubber trees from second-growth forests and fallow land has proven challenging. Previous experiments using machine-learning approaches with hard classifications on remotely sensed data, when faced with the realities of a heterogeneous plant-life mixture and high intra-class variance, have tended to overestimate the areas of rubber tree growth. Our current research sought to: 1) to investigate the potential of using a Mahalanobis typicality model to deal with mixed pixels; and 2) to explore the potential for combining MOderate Resolution Imaging Spectroradiometer (MODIS) imagery with sub-national statistical data on rubber tree areas to map the distribution of rubber tree growth across this mainland Southeast Asia landscape. Our study used time-series MODIS Terra 16-day composite 250 m Normalized Difference Vegetation Index (NDVI) products (MOD13Q1) acquired between March 2009 and May 2010. We used the Mahalanobis typicality method to identify pixels where rubber tree growth had the highest probability of occurring and sub-national statistical data on rubber tree growth to quantify the number of pixels of rubber tree growth mapped per administrative unit. We used Relative Operating Characteristic (ROC) and error matrix analysis, respectively, to assess the viability of Mahalanobis typicalities and to validate classification accuracy. High ROC values, over 0.8, were achieved with the Mahalanobis typicality images of both mature and young rubber trees. The proposed method greatly reduced the commission errors for the two types of rubber tree growth to 1.9% and 2.8%, respectively (corresponding to user’s accuracies of 98.1% and 97.2%, respectively). Results indicate that integrating Mahalanobis typicalities with MODIS time-series NDVI data and sub-national statistics can successfully overcome the earlier overestimation problem.  相似文献   

树轮δ¹³C值方位分布及年际变化的普遍性研究——以中国东部亚热带地区为例     

赵兴云  王建  商志远  钱君龙 《地理科学》2012,(2):193-198

对采自中国东部亚热带地区的浙江天目山、江西庐山及江苏南京紫金山地区的金钱松(Pseudolarix kaemp feri)、冷杉(Abiesfab ricraib)及马尾松(Pinus massoniana)树轮,分别测定它们不同方位10 a、20 a及3 a树轮δ13C序列,探讨不同树种树轮δ13C存在的方位差异与年际变化普遍性。结果表明,在中国东部亚热带地区,树轮δ13C方位差异与年际变化存在普遍性。表现为3个地区、3个树种之间存在差异;同一地区不同树种及相同树种不同个体之间也存在差异;同一个体在相同年份存在方位差异及相同方位存在年际变化等;表明研究树轮δ13C的方位差异与研究其年际变化同样具有重要价值与意义。  相似文献   

Differential stemflow yield from European beech saplings: the role of individual canopy structure metrics          下载免费PDF全文

D. F. Levia  B. Michalzik  K. Näthe  S. Bischoff  S. Richter  D. R. Legates 《水文研究》2015,29(1):43-51

Stemflow production is affected by a suite of biotic and abiotic factors. It has proven difficult to determine the importance of individual canopy structure metrics on stemflow production. The disentanglement of the role and importance of individual canopy structure metrics would advance our understanding of the dynamics of stemflow production. This work employed ten isolated (i.e. no overlapping crowns) experimental European beech (Fagus sylvatica L.) saplings to examine the effects of various canopy structural metrics on stemflow production in east‐central Germany. The following canopy structural metrics were utilized in a hierarchical cluster analysis using Ward's method to separate the saplings into groups: primary branch count per unit projected crown area, secondary branch count per unit projected crown area, total branch count per unit projected crown area, mean branch inclination angle, minimum branch inclination angle, maximum branch inclination angle, total dry woody biomass per unit projected crown area, total foliar dry biomass per unit projected crown area and total dry biomass per unit projected crown area. Cluster group means revealed that saplings, which generate the largest stemflow yields, once controlled for sapling size, have straighter boles (but some trunk lean), more steeply inclined branches, a larger number of branches, more woody surface area and fewer numbers of leaves. Our results may prove valuable as a guide to researchers wishing to couple LiDAR and fine‐scale architectural models with the canopy metrics that govern stemflow to provide a better understanding of the canopy on the hydrology and biogeochemistry of forests. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献