VML在WebGIS图形显示中的应用研究

针对目前被动式WebGIS地图显示的局限,提出了引入VML的解决办法,使客户端容易实现矢量地图显示、地物动态变化显示、专题制图显示等,丰富了WebGIS的地图表现方式。     

Practical Research of IKONOS-2 Geopositioning and Its Accuracy in Tibet of China

This paper presents the studies of the refining of IKONOS-2 RPC, the transform of the datum, the mode of the control point distribution and the method of IKONOS stereo triangulation, so that IKONOS imagery can be used to collect the precise geospatial data and produce the large scale map. The transform between the IKONOS-2 image space and the national coordinate system based on the RPC have been developed, and the results of block adjustment with various control schemes in a practical project near Himalayas have been examined and analysed. The encouraging results of high positioning accuracy have been obtained.     

基于SVG的地理信息编码与DOM交互解析实现

SVG作为新兴的基于XML的矢量图形描述规范，在很多方面与地理信息系统中的基本概念表述一致。在对地理信息进行SVG编码的基础上，利用DOM对地理信息SVG编码文档进行解析，实现了基于SVG的Web地理信息发布实例。实验表明，采用SVG技术的通用性好、矢量显示质量高、响应速度快的优点来开发地理信息的Web应用，也是顺应Web地理信息发布发展需要的。     

保持主分量变换结果信息的量化方法

从主分量变换后图像信息保持的角度出发，充分分析了变换结果存储导致信息丢失的原因；同时以直接线性变换为基础，提出了另外两种新的对主分量变换结果进行量化的方法；并对这3种方法进行了充分的比较，文中最后以信息熵为指标评价了3种方法的优劣。     

北京市地下水动态监测示范工程的建设和应用

北京市地下水动态监测示范工程是北京市科委的重大项目,从1999年开始建设,到2004年4月全面完成.本文详细介绍了该项目的建设及开发内容,以及在北京市地下水动态监测工作中的应用情况.     

地学自由曲面径向基函数网络重建的详细算法

径向基函数(RadialBasisFunction,简称RBF)神经网络是一种理想的地学离散数据网格化工具,能够适应各种不同分布形式和边界条件的数据,收敛速度较快,可以逼近任何复杂曲面。这里详细介绍了RBF神经网络的算法。适当径向基函数的形式和偏差系数是使用RBF神经网络作地学曲面重建的关键。大量的实际数据验证结果表明,当选用Gauss型径向基函数时,一般可获得比较理想的网格化效果,同时具备"曲面平滑"和"拟合度高"的特点。     

测绘情报工作发展战略思考

本文通过对“十五”期间测绘情报工作的回顾，分析了目前测绘情报研究存在的主要问题，讨论了今后测绘情报工作的发展对策。     

Effects of detailed soil spatial information on watershed modeling across different model scales

Hydro-ecological modelers often use spatial variation of soil information derived from conventional soil surveys in simulation of hydro-ecological processes over watersheds at mesoscale (10–100 km²). Conventional soil surveys are not designed to provide the same level of spatial detail as terrain and vegetation inputs derived from digital terrain analysis and remote sensing techniques. Soil property layers derived from conventional soil surveys are often incompatible with detailed terrain and remotely sensed data due to their difference in scales. The objective of this research is to examine the effect of scale incompatibility between soil information and the detailed digital terrain data and remotely sensed information by comparing simulations of watershed processes based on the conventional soil map and those simulations based on detailed soil information across different simulation scales. The detailed soil spatial information was derived using a GIS (geographical information system), expert knowledge, and fuzzy logic based predictive mapping approach (Soil Land Inference Model, SoLIM). The Regional Hydro-Ecological Simulation System (RHESSys) is used to simulate two watershed processes: net photosynthesis and stream flow. The difference between simulation based on the conventional soil map and that based on the detailed predictive soil map at a given simulation scale is perceived to be the effect of scale incompatibility between conventional soil data and the rest of the (more detailed) data layers at that scale. Two modeling approaches were taken in this study: the lumped parameter approach and the distributed parameter approach. The results over two small watersheds indicate that the effect does not necessarily always increase or decrease as the simulation scale becomes finer or coarser. For a given watershed there seems to be a fixed scale at which the effect is consistently low for the simulated processes with both the lumped parameter approach and the distributed parameter approach.     

对江西农经网如何更好地提供信息服务的探讨

分析了江西农村经济信息网(www.jxagriec.gov.cn)的现状,指出农经网信息服务正面临着挑战,并在此基础上阐述了农经网信息服务的发展思路。     

基于MAPGIS的军事标图系统的设计

军事领域是一个非常特殊的行业，信息的安全性和空间数据的多样性是应用开发的重要问题。在全球信息化日趋高速发展和逐步成熟的今天，军队信息化建设也必须与GIS技术紧密结合，跟上时代前进的步伐。较系统地研究了GIS技术在军事标图绘制中的应用和集成问题，并提供了相应的理论方法和实现系统。在此基础上介绍了以MAPGIS为开发平台的军事标绘系统的实用功能和特点。首先分析了军事信息系统对地理信息数据的要求，并且评述了相关领域的研究现状。然后较为系统地介绍了军事标图系统的总体设计，根据军事标绘对象的数据特征，设计符合要求的应用系统提出了面向对象和无缝交互工具等的设计思想。对军标对象数据模型和操作模型进行了详细地阐述和说明，并将这些模型在系统中进行了实现。最后介绍了军事标图系统的主要模块和功能，探讨了今后GIS研究和发展的方向。