Differences in causal reasoning about resource dynamics and consequences for the participatory debate on North Sea fisheries     

M.C. Verweij  W.L.T. van Densen 《Marine Policy》2010

Fishermen, scientists, policy makers, and staff of environmental NGOs (ENGOs) have significantly different understandings of the processes that determine developments in fish stocks. These perception differences hinder the participatory debate on why fish stocks change and which management measures are effective. In this study, differences in causal reasoning about processes between fishermen, policy makers, ENGO-staff, and scientists were examined, regarding four case studies within the management of the fishery on North Sea plaice. First, it appeared that all parties, besides scientists, had difficulty reasoning about long-term effects because of comprehension problems with stock dynamics, and because of short-term economical interests. Second, there were differences in how parties deal with natural variation and interconnectedness of natural and anthropogenic influences. Stock assessment scientists work with single-species models, reducing complexity by using assumptions that rule out variation, in order to inform policy makers about the effect of one isolated management measure. Fishermen on the other hand, relying on information from their daily lives at sea, emphasize complexity and interconnectedness, and the impact of the ever-changing and unpredictable nature. ENGO-staff appeared reluctant to reason about single species and broaden the debate to the ecosystem-level, while emphasizing the effect of man. As a consequence of the diverging perceptions, much time in multi-stakeholder settings is lost on repetitive discussions, mainly on the relative importance of 'nature' versus 'man'. No wonder that policy makers feel lost, and experience processes as very complex. Concluding, to handle these perception differences, there is need for a directive process coordinator, and a more creative informative role for fisheries scientists. Together with all participants, they should map all expectancies and lines of reasoning at the beginning of the debate. This scheme can be relied on during subsequent meetings, in which perceptions can adequately be positioned.  相似文献   

Current shortcomings of global mapping and the creation of a new geographical framework for the world     

DAVID RHIND 《The Geographical journal》2000,166(4):295-305

The vast bulk of topographic mapping - the geographical framework used to underpin many activities of the state and of business - has been created and is maintained to national standards. As a consequence, what is available differs greatly from country to country. Yet there is a range of needs for globally-consistent map information. Such needs have long been recognized: the International Map of the World was an attempt to meet them. A multiplicity of factors has constrained the National Mapping Organizations from meeting this aim. However, new technologies have enhanced our capacity to create a geographical framework almost anywhere in the world. Using such technologies, commercial and other non-commercial bodies (e.g. the US military and its counterparts within NATO) have begun to produce wide-area geographical information. This paper describes the nature of the need for global mapping, the players involved and the drivers and obstacles to progress. It proposes a rapid way to enhance the current situation through public/private sector partnerships based on a combination of skills, information assets and resources. If implemented, this could lead to global coverage of a framework derived from 1:25000 scale mapping within about two years.  相似文献   

A Review of Shallow-Water Mapping Systems   总被引：1，自引：0，他引：1  

Atanu Basu  N. K. Saxena 《Marine Geodesy》1999,22(4):249-257

In recent years shallow-water mapping systems have been developing rapidly for various applications of coastal, nearshore, and other shallow-water regions. Some systems can operate in only 0.5 m deep water, while the operating range of some systems is over 600 m depth. This article reviews the characteristics of nine shallow-water mapping systems developed by seven manufacturers. The design and the data collection methods of these systems are different from each other, and each has its advantage. Most of these systems have been tested in the real environment and are in use for various purposes around the world.  相似文献   

测绘运筹学动态规划简介     

龚强 《测绘与空间地理信息》1999,(2)

本文基于应用,对测绘运筹学动态规划的基本原理、逆序算法、基本概念及最优化原理等作了简要介绍。  相似文献   

《中华人民共和国国家农业地图集》的设计特点     

张龙生 《地理学报》1991,46(1):77-83

《中华人民共和国国家农业地图集》是我国第一部大型综合性农业科学参考地图集。本文探讨了该地图集的设计原则。详述了地图集的设计特点:(1)以宏观农业系统思想为指导,精心选题设计;(2)全面综合地显示我国农业生产的特点和发展变化;(3)综合反映我国地学、农学、生物学的最新科研成果;(4)遥感制图、机助制图和传统制图的有机结合。  相似文献   

Mapping of glaciotectonic deformation in an ice marginal environment with ground penetrating radar   总被引：1，自引：0，他引：1  

Torben Overgaard  Peter Roll Jakobsen   《Journal of Applied Geophysics》2001,47(3-4)

A series of closely spaced parallel ground penetrating radar (GPR) profiles of glaciotectonic deformed glacio-fluvial sediments have been obtained in an ice marginal environment in Northwest Zealand, Denmark. The radar profiles can be differentiated into several radar facies with distinct reflection characteristics. The lithology and depositional environment of the radar facies is interpreted by correlation with information from profiles in gravel pits, geological maps and drill hole data. The radar facies include glaciotectonically disturbed glacio-fluvial sediments, sediments deposited penecontemporaneously with the deformations and sediments deposited post-tectonically. Several thrust planes with dip angles between 25° and 30° as well as major folds and minor faults have been interpreted from the GPR data. The deformation style of the deformed glacio-fluvial sediments is a thin-skinned pro-glacial thrust complex, with associated folding. The deformations have resulted in the present ridge morphology seen in the rim of the composite ridge. Syn- and post-tectonic sediments are deposited on top and in front of the deformed sediments, smoothing the ridge relief created by the thin-skinned thrust complex. A structural geological map constructed from the ground penetrating radar data reveals the extension of the individual radar facies in the thrust complex. Tectonic features such as thrust planes and folds can be followed throughout the mapped area.  相似文献   

缺乏地震动加速度记录地区地震动估计的映射法   总被引：17，自引：2，他引：17  

胡聿贤  周克森 《地震工程与工程振动》1996,16(3):1-10

本文提出了缺乏地震动加速度记录地区地震动估计的映射法、此法的关键步骤是利用缺乏地震动加速度记录地区Ｂ和已有足够地震动加速度记录地区Ａ的地震烈度衰减关系的映射法，从而求得此两地区的映射地震对，使地震对中的地震所给出的两地区的地震烈度相同。  相似文献   

Landslide susceptibility mapping of the slopes in the residual soils of the Mengen region (Turkey) by deterministic stability analyses and image processing techniques   总被引：23，自引：0，他引：23  

C. Gkceoglu  H. Aksoy 《Engineering Geology》1996,44(1-4):147-161

The aim of the present study is to prepare a landslide susceptibility map of a region of about 120 km², between Gökcesu and Pazarköy (around Mengen, NW Turkey) at approximately 10 km north of the North Anatolian Fault Zone, where frequent landslides occur. For this purpose, mechanisms of the landslides were studied by two-dimensional stability analyses together with field observations, and the parameters controlling the development of such slides were identified. Field observations indicated that the failures generally developed within the unconsolidated and/or semiconsolidated soil units in forms of rotational, successive shallow landslides within the weathered zone in Mengen, Cukurca and Sazlar formations. Although consisting of residual soils, Capak and Gökdag formations do not exhibit landslides as the natural slopes formed on these, do not exceed the critical slope angles. Statistical evaluations and distribution of the landslides on the topographical map showed that such parameters as cohesion, angle of internal friction, slope, relative height, orientation of slopes, proximity to drainage pattern, vegetation cover and proximity to major faults were the common features on the landslides. Digital images were obtained to represent all these parameters on gray scale on the SPOT image and on the digital elevation model (DEM) of the area using image processing techniques. Soil mechanics tests were carried out on 36 representative samples collected from different units, and parameters were determined for two-dimensional stability analyses basing on “sensitivity approach” and for the preparation of digital shear strength map. In order to determine the critical slope angle values for the residual soils, a series of sensitivity analyses were realized by using two-dimensional deterministic slope stability analyses techniques for varying values of cohesion, angle of internal friction and slope height along with varying saturation conditions. According to the results of the sensitivity analyses, the Mengen formation was found to be most susceptible unit to landslides, covering about 33.5% of the region studied in terms of surface area. The distribution of the critical slopes were determined by superimposing the critical slope values from sensitivity analyses on slope map of the study area. On the other hand, iso-cohesion and iso-friction maps were produced by locating the values of cohesion and internal friction angles in a geographic coordinate system such that they coincide with sample locations on the DEM and by further interpolation of the values concerned. The pixel values were evaluated in gray scale from 0 to 255, 0 representing the lowest pixel value and 255 representing the highest. Sensitivity analyses on cohesion and angle of internal friction to investigate the effects of these parameters only on stability, revealed that cohesion was effective at a rate of 70% by itself, while angle of internal friction alone controlled the stability by a rate of 30%. The iso-cohesion and iso-friction maps previously obtained were digitally combined in these rates and a “shear strength map” was prepared. The geographic setting of the study area is such that northern slopes usually receive dense precipitation. In relation to this fact, about 42% of the landslides are due north. Thus, a slope orientation map was prepared using the DEM, and slopes facing north were evaluated as being more susceptible to sliding. Proximity to the drainage pattern was another important factor in the evaluation, as streams could adversely affect the stability by either eroding the toe or saturating the slope, or both. When considered together, in conjunction with the field observations, faults and landslides showed a close association. In the area, about 88% of the landslides were detected within an area closer than 250 m to major faults, therefore, a main discontinuity map was produced using the SPOT image of the region, and “proximity to major faults” was evaluated as a parameter as most of the landslides developed in areas where the vegetation was rather sparse. A vegetation cover map was therefore obtained from the SPOT image, and the areas with denser vegetation were considered to be less susceptible to sliding with respect to the areas with less or no vegetation. Having prepared the maps accounting for the distribution of critical slopes, shear strength properties, relative height, slope angle, orientation of the slopes, vegetation cover, proximity to the drainage pattern, geographic corrections were carried on each of these, and a potential failure map was obtained for the residual soils by superimposing all these maps. Next, a classification was performed on the final map and five relative zones of susceptibility were defined. When compared with this map, all of the landslides identified in the field were found to be located in the most susceptible zone. The performance of the method used in processing the images appears to be quite high, the zones determined on the map being the zones of relative susceptibility.  相似文献   

Methodology for mapping shallow groundwater quality in urbanized areas: A case study from Lithuania     

A. A. Klimas 《Environmental Geology》1996,27(4):320-328

Cities have a negative impact on the quality of shallow groundwater. Many of Lithuania's urban residents drink water from dug wells. Moreover, polluted shallow groundwater contaminates deeper aquifers of fresh drinking water. Therefore, this situation should be controlled and managed, as far as possible. In order to evaluate the quality of shallow groundwater in an urban area and to create an optimal monitoring system, an original methodology for groundwater mapping has been proposed. It resembles the GIS (geographical information system) technologies. The set of maps, laid one over another, consists of the following: (1) urbanization map, (2) geological-hydrogeological map, (3) groundwater chemistry map, (4) resulting groundwater chemistry factorial analysis map, and (5) pollution and pollutant transport map. The data obtained from studies on dug and geotechnical wells have been used for compilation of the maps. The system for shallow groundwater monitoring in the city with an area of 70 sq km and a population of 140,000 is proposed to consist of about 30 monitoring wells and several dug wells.  相似文献   

勘查地球化学的现状与未来展望   总被引：28，自引：2，他引：28  

谢学锦 《地质论评》1996,42(4):346-356

勘查地球化学在过去50年发展迅速,并取得巨大成功。从它近年的发展及在中国北京与澳大利亚Townsville召开的第16届及第17届国际地球化学勘查学术讨论会上所表现的创新与非传统性看来,勘查地球化学正在从经验式阶段向革新技术与加强理论研究的新阶段过渡。其主要标志是由于国际地球化学填图研究的进展及各种宽阔地球化学模式的认识,地球化学勘查将逐步成为能左右矿产勘查部署的战略性方法,各种新技术的出现使隐伏区找矿特别是找巨型矿床正在取得重大突破。高质量的地球化学图还将使今后的环境研究更具全球眼光,中国的工作是这些方  相似文献