共查询到20条相似文献，搜索用时 15 毫秒
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端元提取技术是混合像元分解中重要的步骤之一,传统的端元提取方法仅考虑了像元的光谱信息。本文将数学形态学算子扩展到高光谱空间,并应用到端元提取技术中,可以顾及像元的上下文信息。利用AVIRIS高光谱仿真数据对算法进行了实验验证,结果表明本文算法具有较强的抗噪能力和较高的可靠性。在此基础上,结合徐州地区的EO-1 Hyperion高光谱遥感图像,使用本文算法进行了端元提取应用研究,将实验结果与纯净像元指数、顶点成分分析方法做了对比分析和精度评价,证明本文算法是一种可靠的高光谱遥感图像端元提取技术。 相似文献
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供水管网地理信息系统中爆管分析的算法研究 总被引：1，自引：0，他引：1
爆管关阀分析是供水管网地理信息系统中重要的空间分析功能之一,目前已建系统的爆管分析功能存在着算法繁琐或功能简单、不具通用性等缺点。本文以高质量的源数据为基础,根据系统和爆管分析的需求建立合理的数据模型,设计了爆管关阀分析算法,该算法克服现有算法的不足,剔除了可关可不关的阀门,得到正确、经济的关阀门方案,并列出了受影响的用户。将此设计方案应用于"新疆石油管理局供水地理信息系统"中,成功地实现了爆管分析,体现出了该算法简洁、高效、准确、通用的优越性。 相似文献
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A Network Perspective on Spatial Data Infrastructures: Application to the Sub-national SDI of Flanders (Belgium) 总被引：2，自引：0，他引：2
Danny Vandenbroucke Joep Crompvoets Glenn Vancauwenberghe Ezra Dessers Jos Van Orshoven 《Transactions in GIS》2009,13(S1):105-122
In order to provide a basis for quantitative and qualitative assessment of SDI-performance, a clear definition and a theoretical framework for SDI are needed. From the various definitions and frameworks of SDI available in the literature, the productional and the geographic information process perspective were selected, combined and extended. From the productional perspective, SDI-development is a dynamic process in which suppliers and users of spatial data interact to add value to the data by using them in applications and processes. The geographic information process perspective incorporates the "information acquisition – delivery – usage" chain. The extension proposed in this article leads to a network perspective on SDI. The nature of this perspective is described for the Flemish SDI. Its applicability to characterise and underpin the assessment of SDI is tested using a Social Network Analysis (SNA) focusing on the network structure parameters "density", "distance" and "centrality". The SNA confirms the applicability, usability and extensibility of the network perspective to characterize the SDI, to describe the data flows between stakeholders and to analyse the behaviour of the different (types) of stakeholders within the network. We conclude that SNA should likely be complemented by an impact analysis of different SDI setups on business processes which will provide a good basis for a holistic SDI-performance assessment. 相似文献
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The activities of the Ionosphere Working Group of the International GPS Service (IGS) 总被引：5，自引：2，他引：3
This article is based on a position paper presented at the IGS Network, Data and Analysis Center Workshop 2002 in Ottawa,
Canada, 8–11 April 2002, and introduces the IGS Ionosphere Working Group (Iono_WG). Detailed information about the IGS in
general can be found on the IGS Central Bureau Web page: http://igscb.jpl.nasa.gov. The Iono_WG commenced working in June
1998. The working group's main activity currently is the routine production of ionosphere Total Electron Content (TEC) maps
with a 2-h time resolution and daily sets of GPS satellite and receiver hardware differential code bias (DCB) values. The
TEC maps and DCB sets are derived from GPS dual-frequency tracking data recorded with the global IGS tracking network.
In the medium- and long-term, the working group intends to refine algorithms for the mapping of ionospheric parameters from
GPS measurements and to realize near–real–time availability of IGS ionosphere products. The paper will give an overview of
the Iono_WG activities that include a summary of activities since its establishment, achievements and future plans.
Electronic Publication 相似文献
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结合遥感影像的特点,提出一种模糊逻辑系统和神经网络中的BP算法相结合的模糊神经网络,利用其进行整个遥感图像的分类,并和典型的BP神经网络进行对比,发现其优点以及存在的问题。 相似文献
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Dhaval Vyas N.S.R. Krishnayya K.R. Manjunath S.S. Ray Sushma Panigrahy 《International Journal of Applied Earth Observation and Geoinformation》2011
There is an urgent necessity to monitor changes in the natural surface features of earth. Compared to broadband multispectral data, hyperspectral data provides a better option with high spectral resolution. Classification of vegetation with the use of hyperspectral remote sensing generates a classical problem of high dimensional inputs. Complexity gets compounded as we move from airborne hyperspectral to Spaceborne technology. It is unclear how different classification algorithms will perform on a complex scene of tropical forests collected by spaceborne hyperspectral sensor. The present study was carried out to evaluate the performance of three different classifiers (Artificial Neural Network, Spectral Angle Mapper, Support Vector Machine) over highly diverse tropical forest vegetation utilizing hyperspectral (EO-1) data. Appropriate band selection was done by Stepwise Discriminant Analysis. The Stepwise Discriminant Analysis resulted in identifying 22 best bands to discriminate the eight identified tropical vegetation classes. Maximum numbers of bands came from SWIR region. ANN classifier gave highest OAA values of 81% with the help of 22 selected bands from SDA. The image classified with the help SVM showed OAA of 71%, whereas the SAM showed the lowest OAA of 66%. All the three classifiers were also tested to check their efficiency in classifying spectra coming from 165 processed bands. SVM showed highest OAA of 80%. Classified subset images coming from ANN (from 22 bands) and SVM (from 165 bands) are quite similar in showing the distribution of eight vegetation classes. Both the images appeared close to the actual distribution of vegetation seen in the study area. OAA levels obtained in this study by ANN and SVM classifiers identify the suitability of these classifiers for tropical vegetation discrimination. 相似文献
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基于XML Schema地球系统科学数据的元数据扩展机制 总被引：5，自引：0，他引：5
概述目前国内外地学数据共享中元数据的应用,分析地球系统科学数据的学科特点:数据量大、学科复杂、元数据标准多,从而论证在地球系统科学数据共享网的开发和研究中元数据扩展的必要性,论述元数据扩展的基本方法、抽象模型和基本原则,总结地球系统科学数据共享网核心元数据的多学科扩展表达,最后,论述地球系统科学数据共享网中元数据扩展机制的实现,以及利用XML Schema文档的可扩展性,阐述基于XML Schema地球系统科学数据的元数据扩展机制,实现地球系统科学数据元数据的多学科扩展. 相似文献
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《International Journal of Digital Earth》2013,6(9):923-943
ABSTRACTLinked Data is known as one of the best solutions for multisource and heterogeneous web data integration and discovery in this era of Big Data. However, data interlinking, which is the most valuable contribution of Linked Data, remains incomplete and inaccurate. This study proposes a multidimensional and quantitative interlinking approach for Linked Data in the geospatial domain. According to the characteristics and roles of geospatial data in data discovery, eight elementary data characteristics are adopted as data interlinking types. These elementary characteristics are further combined to form compound and overall data interlinking types. Each data interlinking type possesses one specific predicate to indicate the actual relationship of Linked Data and uses data similarity to represent the correlation degree quantitatively. Therefore, geospatial data interlinking can be expressed by a directed edge associated with a relation predicate and a similarity value. The approach transforms existing simple and qualitative geospatial data interlinking into complete and quantitative interlinking and promotes the establishment of high-quality and trusted Linked Geospatial Data. The approach is applied to build data intra-links in the Chinese National Earth System Scientific Data Sharing Network (NSTI-GEO) and data -links in NSTI-GEO with the Chinese Meteorological Data Network and National Population and Health Scientific Data Sharing Platform. 相似文献
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The growing penetration of GPS equipped smartphones allowing users to constantly share geographic information on their current whereabouts has led the way to an augmentation of existing Social Network Sites with location‐based features or the creation of new ones exclusively around geographic information. Within these Location Based Social Networks vast amounts of geographic information are allocated, which attracted the attention of researchers with various scientific backgrounds. This article presents a comprehensive definition of this special type of Social Network Site and an overview of research activities, which are currently conducted using the data. Finally, a research agenda for GIScience is drawn from existing research directions. 相似文献
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以"中国地壳运动观测网络"观测数据以及陕西省GPS观测网2001-2005年的5期观测数据为基础,应用GAM IT/GLOBK软件对数据进行精密解算,获得了陕西省关中地区2001~2005年相对于鄂尔多斯块体以及关中地区内部彬县站点的水平运动速度场。并结合板块构造学原理进一步分析了关中及其邻区的地壳运动规律:①GPS技术用于地壳运动的监测是可行的;②相对于较稳定的鄂尔多斯块体,关中地区整体呈现不连续性逆时针旋转;③关中地区中西部存在多处应力集中区,地壳的相对水平运动较为激烈;④关中地区中部泾灞隐伏断裂带附近地壳水平运动激烈,属潜在多震区。 相似文献
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分析了现有的三维数据模型——实体模型、不规则四面体模型,在此基础上研究了三维实体的对象化过程,并提出了一种基于面向对象的实体-不规则四面体格网(OOSolid-Tetrahedral Network,简称OOS-TEN)的三维数据模型构建方法,对三维空间数据信息进行有效的组织,并建立基于Oracle Spatial的三维数据信息数据库,从而对三维数据信息进行有效的组织和管理。 相似文献
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张莉 《测绘与空间地理信息》2002,25(3):35-37
简要介绍了如何开发基于网络环境下的测绘资料查询系统 ,并介绍了利用ASP技术实现网络中对Web数据库中测绘资料信息的查询 ,通过实例说明基于网络环境下测绘资料查询系统的开发过程。 相似文献
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基于退火BP神经网络的GPS高程转换 总被引：1，自引：0，他引：1
阐述模拟退火算法的基本思想和原理,提出并介绍模拟退火算法优化的BP神经网络模型在GPS高程转换中的具体应用,同时编写相应的MATLAB处理程序,结合大量数据进行仿真实验,结果表明文中提出的退火BP神经网络模型具有收敛速度快、精度高、避免陷入局部最小的优良特性。 相似文献
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地籍测量工作是地籍管理和地籍信息系统建设的基础,在地籍测量土地状况利用调查中,查清各类土地的分布和利用状况需要有一个准确的定位。随着GPS测量技术的飞速发展和不断成熟,网络GPS-RTK技术以其高精度和高自动化优势在地籍测量中的作用越来越重要。在手机网络流行的今天,网络GPS的应用也越来越便利。本文结合河南理工大学新校区地籍测量工作,首先介绍网络RTK组成及定位原理,分析了网络RTK测图的关键技术,重点说明了网络GPS-RTK的数据采集作业方法以及数据处理和在地籍测量中的使用步骤,得出了网络GPS是一个快速和准确的测量方法,具有较强的实用性,可以满足地籍测量的需要。 相似文献
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三维空间数据模型集成的概念框架研究 总被引：96，自引：6，他引：96
本文对三维空间数据模型的研究与发展进行了总结,分析了三维空间数据的特点以及数据模型集成的必要性。结合三维ＧＩＳ在城市、地质、海洋等领域的具体应用,提出三种三维空间数据模型集成：用于城市三维构模基于ＴＩＮ和ＣＳＧ的集成模型;用于地质,海洋等领域的基于八叉树和四面体格网的混合模型;具有一般性的矢量栅格集成的三维空间数据模型。 相似文献