SOFTWARE REVIEWS

Data Desk 3.0 1990 . GISTARS. 1990 . Wayne L. Myers, Codirector Microcase Analysis System , Version 2.1, 1990. PAMAP , Version 2.22. US-GEO-GRAPHICS, Version CGA, EGA. 1987.     

GIS-Based Probabilistic Mapping of Landslide Hazard Using a Three-Dimensional Deterministic Model

Based on a new Geographic Information Systems (GIS) grid-basedthree-dimensional (3-D) deterministic model and taking the slopeunit as the mapping unit, this study maps landslide hazard usingthe 3-D safety factor index and failure probability. Assuming theinitial slip to be the lower part of an ellipsoid, the 3-D critical slipsurface in the 3-D slope stability analysis is located by minimizingthe 3-D safety factor using the Monte Carlo random simulation.The failure probability of the landslide is calculated using anapproximate method in which the distributions of c, andthe 3-D safety factor are assumed to be in normal distribution.The method has been applied to a case study on three-dimensionallyand probabilistically mapping landslide hazard.     

用苹果机实现24路气象电报自动转报系统

本文介绍了用两台苹果机实现的气象电报自动转报系统的硬件组成,软件组成和实现的功能。     

WT-1A气象卫星接收设备的改进与开发应用

在1984-1985年期间,对专用卫星接收设备WT-1A进行了一系列改进:能接收线、园双极化的天线头,降低整机噪声温度,提高整机频率稳定性和扩展解调器门限电平。实现了用三米孔径的小型抛物面天线,接收GMS-3同步气象卫星和NOAA系列极轨气象卫星两种高分辨云图,一年多业务应用证明,整机改进设计技术合理,信噪比高,图象质量优良,效果明显。 1986年12月初已通过技术鉴定。     

An integer ambiguity resolution procedure for GPS/pseudolite/INS integration

In order to achieve a precise positioning solution from GPS, the carrier-phase measurements with correctly resolved integer ambiguities must be used. Based on the integration of GPS with pseudolites and Inertial Navigation Systems (INS), this paper proposes an effective procedure for single-frequency carrier-phase integer ambiguity resolution. With the inclusion of pseudolites and INS measurements, the proposed procedure can speed up the ambiguity resolution process and increase the reliability of the resolved ambiguities. In addition, a recently developed ambiguity validation test, and a stochastic modelling scheme (based on-line covariance matrix estimation) are adapted to enhance the quality of ambiguity resolution. The results of simulation studies and field experiments indicate that the proposed procedure indeed improves the performance of single-frequency ambiguity resolution in terms of both reliability and time-to-fix-ambiguity.     

微机GIS系统软件设计的原理与方法

本文介绍了北京大学遥感技术应用研究所(国家遥感中心技术培训部)于1988年4月推出的地理信息系统通用软件PURSIS的设计原理与方法。由于它是在IBMPC/XT,AT及系列兼容机上研制的,因此便于推广使用。为了克服微机在速度和容量上的种种限制,PURSIS系统采用了一些较复杂的技术手段,使得与其它系统相比,具有如下明显特点:(1)利用软件技术,为图形的输入和编辑创立了一个良好的交互式工作环境,使用户能方便地输入和修改各种地图。(2)采用压缩编码技术存贮图形和图像数据,从而大大减轻了微机系统的空间负担。(3)设计了高效率的数据格式转换算法,使矢量数据能快速转换为网格数据。(4)设计了COLOR 136软件,将廉价的COLOR-400卡支持的16种颜色扩充为136种颜色,成功地解决了专题图件的显示问题。(5)解决了图形数据和属性数据的联合操作问题,使用户能在图的逻辑概念上进行多种操作。此外,数字地形模型和其它数据在操作时的联系甚为紧密。(6)提供了一些常用的应用工具,如专家权重、叠加分类、专家命题等模型。使用户在这些模型支持下解决一些各自的专业问题。(7)解决了FORTRAN语言、编译DBASE Ⅲ和8086宏汇编语言之间的相互调用问题,使系统设计灵活多变,并能充分利用微机的系统功能。     

Economic base model for the Guadiana estuary,Portugal an application for Integrated Coastal Zone Management

The concept of base-multiplier analysis is that export activities constitute the economic base of a region, whereas the other economic activities that sell their goods and services to the local residents grow or shrink depending on the performance of the base activities. These concepts, with origins extending at least as far back as the early 1900s, have reached maturity and are widely applied. The attractiveness of an economic base model (EBM) draws in its simplicity in expressing the power of demand in regional income determination. Extensive literature has grown up around the economic base theory, however, systematic publications concerning empirical application are scarce and focus mostly on the socio-economic dimension of the analyzed system. Such territorially oriented economic models are useful in a variety of decision making procedures; preparation of annual budgets, short-run market demand forecasting, longer-term growth strategies. The purpose of this article is to present a practical application of EBM to the geographical area of the Guadiana Estuary, on the south coast of Portugal. The interest of the EBM application in this case study includes its integration in a broader project that applies a Systems Approach Framework (SAF) towards Integrated Coastal Zone Management (ICZM). There are three pillars of sustainability considered here: social, ecological and economic, hence, the article not only describes EBM application but also how it has been use to demonstrate a chain of events resulting from the interaction between the ecological and the socio-economic sub systems of the area. The results obtained will probably raise the usual criticism to which the economic base model has been exposed previously; however it provides unequivocal evidence that a truly interdisciplinary approach to a given territorial target can be successfully shared with end users and the research community.     

Testing the application of the Systems Approach Framework (SAF) for the management of eutrophication in the Ria Formosa

The SAF (Systems Approach Framework) encompasses the ecological, social and economic components of coastal zones and aims to establish a permanent dialogue between scientists, stakeholders and policy makers working within European coastal zones for developing effective ICZM (Integrated Coastal Zone Management). The objective of the present study is to test the application of the SAF for defining eutrophication management options in the Ria Formosa, Portugal. Stakeholders were identified and the issue of eutrophication was agreed upon. Having defined the virtual system, the conceptual model of the Ria Formosa was developed. The formulation of the conceptual model into a mathematical model representing the ecological, social and economic components of the system is then discussed. The linking variable of the three components within the simulation model, as well as the scenarios to be run are then explored. The role of scientists as facilitators within the deliberation process is discussed, and a format by which the final output package could be disseminated is suggested. This case study demonstrates how the SAF could successfully be applied to the management of eutrophication in the Ria Formosa. It also suggests ways in which this approach may be adapted to address unique coastal systems with specific system characteristics.     

Precise Multibeam Acoustic Bathymetry

The maximum error in ocean depth measurement as specified by the International Hydrographic Organization is 1% for depth greater than 30m. Current acoustic multibeam bathymetric systems used for depth measurement are subject to errors from various sources which may significantly exceed this limit. The lack of sound speed profiles may be one significant source of error. Because of the limited ability of sound speed profile measurement, depth values are usually estimated using an assumed profile. If actual sound speed profiles are known, depth estimate errors can be corrected using ray-tracing methods. For depth measurements, the calculation of the location at which a sound pulse impinges on the sea bottom varies with the variation of the sound speed profile. We demonstrate that this location is almost unchanged for a family of sound speed profiles with the same surface value and the same area under them. Based on this observation, we can construct a simple constant-gradient equivalent sound speed profile to correct errors. Compared with ray-tracing methods, the equivalent sound speed profile method is more efficient. If a vertical depth is known (or independently measured), then depth correction for a multibeam system can be accomplished without knowledge of the actual sound speed profile. This leads to a new type of precise acoustic multibeam bathymetric system.     

Perceptions of Local People toward Wild Edible Plant Gathering and Consumption: Insights from the Q-method in Hani Terraces

Wild edible plants (WEPs) can provide a variety of provisioning services and cultural services but they are currently under-utilized. Understanding farmers’ perceptions of the collection and consumption of wild edible plant resources is essential for promoting local socio-ecological system resilience and local wild plant resource use. This paper uses the Q-method to investigate the main perspectives of farmers toward collecting and consuming wild edible plants in the Honghe Hani Terraces region of Yunnan Province. This analysis identified four main perspective types among the farmers, including market-driven, household user-driven, cultural service seekers, and tradition followers. It revealed the main factors that limit and facilitate farmers’ WEP collection and consumption, including limitations due to loss of traditional knowledge, and changes in socioeconomic conditions that negatively affect WEP collection and consumption; while, on the other hand, the demand for WEP-related cultural services and the presence of a strong culture slowed down changes in dietary structure, which in turn have maintained WEP collection and consumption. The Q-method can help in identifying the relationship between community residents and local wild plant resource use in rapidly transitioning areas and in identifying the barriers that affect the resilience of local socio-ecological systems.