小清河滞洪区洪灾监测信息系统的研究与建立

应用机载合成孔径雷达监测洪水势态,离不开洪灾监测信息系统的支持,两者有机的结合,能充分发挥遥感和地理信息系统在防洪减灾应用中的优越性。本文以小清河滞洪区为实验区,从系统目标、数据层及其来源、数据编码、分析模型等几个方面,介绍了该区洪灾监测信息系统的建立情况。     

矢量电子地图的线目标在线简化

为了适应实时ＧＩＳ的变比例尺显示与网络ＧＩＳ的快速矢量数据传输，提出了数字地图的在线综合概念，讨论了对线目标的在线简化算法。提出的两个在线简化算法都是对ＤＰ简化算法进行改造，使算法对时间的复杂度从θ（ｎ）～θ（ｎ２）的乘法运算改进为θ（１）～θ（ｎ）的赋值运算，并讨论了减少算法所涉及的空间复杂度的可能性     

中国热带东,西部地区冬季气候的差异与橡胶树的引种

由于青藏高原的动力影响，使得西部地区冬季出现下沉气流，多日照，利于橡胶树的越冬，而东部则出现上升气流，少日照，不利越冬，又由于青藏高原大山体，冬季明显地阻挡低层空气平流，导致高原南侧的西部地区冬季降温和缓，有利橡胶树越冬，而东部地区因无高大山体阻挡，寒潮初期降温剧烈，后期低温阴雨天气持续甚久，易导致橡胶树的严重寒害。     

乌鲁木齐河山区流域360年径流量的重建

本文利用在乌鲁木齐河山区流域所建立的树轮年表，重建了乌鲁木齐河山区流域３６０年上年７月～当年３月的平均径流量。校准方程的相关系数为０．６７０，交叉检验的误差缩减值达０．３６６。在重建的３６０年径流量的变化中，有４个偏丰期和３个偏枯期，第２，３两个偏丰期与乌鲁木齐河河源１号冰川的两次冰进期相对应。对重建径流量的丰枯频率分析发现，平水年份出现最多，偏枯水年份多于偏丰水年份约５．８％，特枯水年没有出现，特丰水年出现６次，约占１．７％。这表明３６０年来径流量变化基本上稳定。     

基于面向对象的空间目标3维交互式建模的设计

3维数据模型的建立是实现真3维GIS的一个核心问题。在充分分析现有3维数据模型的基础上，比较了传统模型的优缺点。针对空间目标建模的特点，设计了一种面向对象的3维数据模型。考虑到软件的实用性和可扩展性，着重论述了3维交互式设计及数据管理。     

The method of design for seismic data database system based on tree structure

Introduction In recent years, with the development of earthquake observation technology, increasing ofobservation stations and improvement of observation instruments which are digitalized and con-nected by network, a great deal of data is recorded, to some extend, which brings difficulty for usto manage and store them. It leads to traditional methods, which use the file system to managemass data, could not satisfy our requirement, and it is necessary to find a new method in place oftradit…     

电子图档的高效管理

通过对前期CAD图档管理系统失败原因进行分析,明确了系统管理的目标,并与软件供应商合作,解决了实施中遇到的问题。     

Local provenance in rehabilitation of degraded landscapes: a case study from the Hawkesbury–Nepean catchment, Australia

Throughout Australia thousands of volunteers are engaged in Landcare projects that should help rehabilitate degraded landscapes. Many of these projects involve tree planting, but their seed is not necessarily of local provenance. Based on a survey of 85 Landcare groups working in the Hawkesbury–Nepean catchment, data were collected about Landcare groups' knowledge of their seed source, understanding of local provenance and the ecosystem in which they were planting trees and the source of funding for their projects. The findings from the study indicate that about one in five (21%) of the groups surveyed that introduced plant material were not aware of local provenance issues. Indirect indications were that a large number of Landcare groups state-wide may be doing more harm than good to the landscape while trying to rehabilitate it. The data also showed that one in seven (13%) of the groups funded by the Australian Government through the Natural Heritage Trust (NHT) had limited awareness of local provenance issues. With millions of dollars being spent on 'works on the ground', it would be prudent to allocate some funds to document and monitor current Landcare activities, so that the environmental outcomes can be quantified and more effective Landcare policies can be developed in the future.     

A critical evaluation of multi‐proxy dendroclimatology in northern Finland

Twentieth‐century summer (July–August) temperatures in northern Finland are reconstructed using ring widths, maximum density and stable carbon isotope ratios (δ¹³C) of Scots pine tree rings, and using combinations of these proxies. Verification is based on the coefficient of determination (r²), reduction of error (RE) and coefficient of efficiency (CE) statistics. Of the individual proxies, δ¹³C performs best, followed by maximum density. Combining δ¹³C and maximum density strengthens the climate signal but adding ring widths leads to little improvement. Blue intensity, an inexpensive alternative to X‐ray densitometry, is shown to perform similarly. Multi‐proxy reconstruction of summer temperatures from a single site produces strong correlations with gridded climate data over most of northern Fennoscandia. Since relatively few trees are required (<15) the approach could be applied to long sub‐fossil chronologies where replication may be episodically low. Copyright © 2010 John Wiley & Sons, Ltd.