主流数字存储技术的发展

本文主要介绍了存储技术的发展历史及目前正在使用的主要的存储技术。文中讲 述了SCSI技术、Fibre Channel技术和RAID技术。介绍了DAS技术、NAS技术 和SAN技术,同时还对磁带库中用到的DAT技术、DLT技术、和LTO技术进 行了介绍。最后对今年新起的iSCSI技术进行了说明。     

移动GIS的体系结构与关键技术

阐述了移动GIS的概念,提出了一个由表示层、逻辑层和数据层所构成的分布式体系结构,介绍了移动接入技术、移动访问技术、移动定位技术、嵌入式技术和语音技术等关键技术。     

“数字城管”中无线数据采集系统的设计与实现

无线数据采集系统涉及多种技术,这些技术对其建设有非常重要的作用。对"数字城管"的系统结构、功能模块作简要介绍,分析、设计和实现"数字城管"中无线数据采集子系统,并深入探讨开发该子系统的关键技术,即无线定位技术、嵌入式GIS技术、GPRS通信技术、数字图像压缩技术、断点续传技术和基于XML的Web Service等。     

基于CORS系统的地质灾害监测预警系统的设计与实现

主要论述了以河北省CORS系统为基础,综合运用GNSS卫星空间定位技术、计算机技术、通讯技术、网络技术、光伏技术、物联网技术等现代技术手段,对可能由地表位移引起的地质灾害进行实时监测、预警和形变分析,建立地质灾害监测预警系统的设计思路和实现过程。     

网络RTK技术在城市规划测量中的应用

随着GPS技术、计算机技术、网络技术的发展,网络RTK技术得到快速的发展和应用。本文简要介绍了GPS网络RTK技术及其工作原理,阐述了其技术优势和特点,结合实际工作,介绍了其在城市规划测量领域内的应用。     

DMC＋4小卫星在国际灾害监测中的应用与评价

针对国际灾害监测星座应用技术和中国各种自然灾害的现状,着重研究了DMC(DisasterMonitoringConstellation)星座应用技术和DMC 4小卫星的数据特点,研究了利用小卫星星座对防灾、抗灾救灾的突出作用,研究了小卫星地面系统集成技术和星地一体化运营、管理和控制体系,以便进一步推动国内小卫星技术、遥感应用技术、卫星星座技术、天地一体化运管控技术和机制创新的发展。促进中国灾害监测星座的研制,最终实现对各种自然灾害的实时、动态监测。     

构建智能交通地理信息及定位平台

计算机技术、通信技术、现代控制技术、全球定位技术和地理信息系统技术为智能交通系统 (ITS)的建设提供了可靠的技术支撑。描述地球表面的基础地理信息数据是国家空间数据基础设施建设中的重要组成部分。交通地理信息及定位平台是面向交通运输 ,以地理信息系统和空间定位技术为依托的广泛概念 ,构架交通地理信息及定位平台 ,提供车辆在四维时空中的位置和有关空间目标描述的技术和信息 ,为实现交通智能化奠定基础。     

Ajax技术在WebGIS中的应用与研究

通过介绍Ajax技术,研究基于Ajax技术的WebGIS原理和实现方法,并和WebGIS的其它不同实现方法进行了对比。相对基于其他Web技术的WebGIS来说,基于Ajax技术的WebGIS具有不受浏览器限制、访问速度快捷、开发方便、费用低廉、可以实现功能定制和扩充、可以在客户端和服务器之间异步通讯等优点。因此,基于Ajax技术的WebGIS可能成为未来WebGIS发展的主流方向。     

构建地理空间信息网格基础底层的若干支撑技术

地理空间信息网格基础底层的支撑技术主要有地理空间信息网格计算结点的构建技术、传统网络协议技术、下一代网络协议技术、接口技术等。作为创新技术,地理空间信息网格必须依托已有技术,加之相关领域及更先进技术的支持,才会有发展和前途。     

空间数据挖掘方法综述

空间数据挖掘和知识发现是空间数据库技术、空间数据荻取技术、计算机技术、网络通信技术和管理决策支持技术等发展到一定阶段的产物,是多学科相互交融和相互促进的新兴边缘学科,汇集了人工智能、模式识别、数据库、空间信息学、统计学等各学科技术的成果。如何在浩瀚的空间数据和人们的知识渴求之间建立一个桥梁的确是一个巨大的挑战,而以聚类、分类等人工智能技术为基础的空间数据挖掘为迎接这个挑战提供了新的支撑技术。总结了空间数据挖掘方法的国内外研究现状,为深入研究空间数据挖掘方法提供参考价值。     

Web GIS在广西水库管理信息系统中的应用

地理信息是水利信息化工作的重要基础之一,水利行业需要运用先进的信息管理手段来提高工作效率,推进信息化建设进程,地理信息系统(GIS)技术为水利行业信息管理的标准化、网络化、空间化提供了有效的工具。广西水库管理信息系统是一个充分利用最新发展的计算机应用技术,采用信息技术、可视化技术、多媒体技术,结合行业规划及管理需要,各种功能完善的基于WebGIS的水库管理地理信息系统。本文介绍基于WebGIS的广西水库管理信息系统的设计和实现,阐述WebGIS技术在水库管理中的重要作用和成功应用。     

遥感技术在景观生态学研究中的应用

景观生态学是一门新兴的宏观生态学分支学科，自20世纪80年代以来，其研究内容和方法论的发展与遥感、GIS等现代对地观测技术的发展紧密联系在一起。对近年来遥感技术在景观生态学中的运用，从景观结构研究、功能研究、动态研究、尺度研究以及景观生态学应用研究五个方面加以总结，进而分析遥感技术在景观生态学研究中的应用优势特征和目前存在的主要问题，并对未来遥感技术在景观生态学研究的应用发展方向提出意见和建议。     

遥感图像准无损压缩技术的研究

提出了一种基于图像恢复技术的遥感图像压缩技术,在提高遥感图像压缩比的同时,使压缩后的重建图像质量达到准无损的技术要求。对SRTF、TM图像的试验结果表明,该技术是可行的。     

An efficient technique for creating a continuum of equal-area map projections

Equivalence (the equal-area property of a map projection) is important to some categories of maps. However, unlike for conformal projections, completely general techniques have not been developed for creating new, computationally reasonable equal-area projections. The literature describes many specific equal-area projections and a few equal-area projections that are more or less configurable, but flexibility is still sparse. This work develops a tractable technique for generating a continuum of equal-area projections between two chosen equal-area projections. The technique gives map projection designers unlimited choice in tailoring the projection to the need. The technique is particularly suited to maps that dynamically adapt optimally to changing scale and region of interest, such as required for online maps.     

A Novel Approach of Despeckling SAR Images Using Nonlocal Means Filtering

Synthetic aperture radar (SAR) is a day and night, all weather satellite imaging technology. Inherent property of SAR image is speckle noise which produces granular patterns in the image. Speckle noise occurs due to the interference of backscattered echo from earth’s rough surface. There are various speckle reduction techniques in spatial domain and transform domain. Non local means filtering (NLMF) is the technique used for denoising which uses Gaussian weights. In NLMF algorithm, the filtering is performed by taking the weighted mean of all the pixels in a selected search area. The weight given to the pixel is based on the similarity measure calculated as the weighted Euclidean distance over the two windows. Non local means filtering smoothes out homogeneous areas but edges are not preserved. So a discontinuity adaptive weight is used in order to preserve heterogeneous areas like edges. This technique is called as discontinuity adaptive non local means filtering and is well-adapted and robust in the case of Additive White Gaussian Noise (AWGN) model. But speckle is a multiplicative random noise and hence Euclidean distance is not a good choice. This paper presents evaluation results of using different distance measures for improving the accuracy of the Non local means filtering technique. The results are verified using real and synthetic images and from the results it can be concluded that the usage of Manhattan distance improves the accuracy of NLMF technique. Non local approach is used as a preprocessing or post processing technique for many denoising algorithms. So improving NLMF technique would help improving many of the existing denoising techniques.     

Indusion: Fusion of Multispectral and Panchromatic Images Using the Induction Scaling Technique

The fusion of multispectral (MS) and panchromatic (PAN) images is a useful technique for enhancing the spatial quality of low-resolution MS images. Liu recently proposed the smoothing-filter-based intensity modulation (SFIM) fusion technique. This technique upscales MS images using bicubic interpolation and introduces high-frequency information of the PAN image into the MS images. However, this fusion technique is plagued by blurred edges if the upscaled MS images are not accurately coregistered with the PAN image. In the first part of this letter, we propose the use of the Induction scaling technique instead of bicubic interpolation to obtain sharper, better correlated, and hence better coregistered upscaled images. In the second part, we propose a new fusion technique derived from induction, which is named ldquoIndusion.rdquo In this method, the high-frequency content of the PAN image is extracted using a pair of upscaling and downscaling filters. It is then added to an upscaled MS image. Finally, a comparison of SFIM (with both bicubic interpolation and induction scaling) is presented along with the fusion results obtained by IHS, discrete wavelet transform, and the proposed Indusion techniques using Quickbird satellite images.     

利用GPS定位技术建立沛县地籍测量控制网

随着GPS定位技术的快速发展，GPS定位技术在工程测量领域的应用越来越广泛，从控制测量、地形测图，到施工放样都发挥了重要的作用。本文主要叙述了利用GPS定位技术建立沛县地籍控制网的情况。     

Total information content as an index of soil moisture

Accurate estimation of soil moisture through remote sensing technique has been a challenge till date. In optical and thermal remote sensing, there is no index developed to detect the changes in soil moisture levels. In microwave region, soil roughness and other target parameters equally affect the technique for soil moisture estimation. Therefore, a computational technique in C language based on Shannon’s Information Theory (Shannon, 1948) has been developed to calculate total information content from multispectral radiometer data. The total information content is a compressed single value, which quantifies the information content of soil spectral reflectance in the electromagnetic spectrum range (400–1100 nm) under study. This technique was tested over a wide range of soil moisture levels. The study revealed that as compared to other techniques total information content index is very sensitive to change in moisture content of soil. This technique could not only quantify the soil moisture content in optical and near infra red region, but also led to a simplified one dimensional separability and clustering analysis.