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Surfaced roads, including gravel roads, total 510,000 km, or 37.5 percent of the Soviet Union's motor-road net of 1.4 million kilometers, the rest consisting of dirt roads. Only about 260,000 km, or less than one-fifth, consists of blacktop or cement or asphalt concrete highways. The lack of roads tends to cause considerable losses to the Soviet economy, particularly in agriculture. An accelerated road-building program is therefore under way, with the current five-year plan (1971–75) calling for the construction or reconstruction of 110,000 km of improved surfaced roads (blacktop and cement or asphalt-concrete) compared with 75,000 km added in the preceding five-year period (1966–70). The densest road nets in the USSR are found in the Baltic republics, in Transcaucasia, Moldavia, the Ukraine and Belorussia. The lowest road-density indices apply to the Russian republic and to Kazakhstan.  相似文献   

3.
We examined whether highway traffic volume changed the rates of movement (habitat permeability) for ten mammalian species in the central Canadian Rocky Mountains. Winter track count data were collected on four highways of varying traffic volume: the Trans-Canada Highway (TCH) (14,000 annual average daily traffic [AADT]) and 1A Highway (3,000 AADT) in Banff National Park and the Highway 40 (5,000 AADT) and Smith Dorrien Trail in Kananaskis Country (2,000 AADT). Permeability represented the ratio of road crossing tracks/km to tracks/km on transects adjacent to roads. We compared permeability at the community level and for carnivore and ungulate guilds, using a Kruskal–Wallis H -test. Traffic volume significantly reduced habitat permeability for the community ( P  < 0.05). Pair-wise Kruskal–Wallis tests showed that habitat permeability was significantly reduced for carnivores at high traffic volume ( P  = 0.008) and for ungulates at very high traffic volume ( P  < 0.043). Cross-referencing with winter traffic counts, we found movement was impaired for carnivores when traffic ranged from 300 to 500 vehicles per day (VPD) and for ungulates between 500 and 5,000 VPD. Our results indicated that the TCH requires mitigation to restore habitat permeability for all species and yielded strong evidence that the Highway 40 is a priority for mitigation.  相似文献   

4.
The article discusses the understanding of the road as a collective duty and institutionalized public space in late medieval Finland and the Swedish realm, as presented in the legislation of King Magnus Erikssons' law (landslag) of the late 1340s. After an introduction on the nature of past scholarship on the history of roads in Europe and Finland, the theoretical framework on the production and social implications of space on historical roads is discussed. The spatial understanding of the road in late medieval Finland is then studied in the context of medieval normative legislation, of which the main interest here is on King Magnus Eriksson's law, which was the major medieval law code valid in Finland. In the code, issues concerning roads and their maintenance are distributed to various sections of the law, but the main body of the legislation is set in Bygningabalken and Edsöresbalken. The analysis shows that, in the bygningabalken, the road and facilities attached to it such as bridges were rather exclusively discussed in the context of common duty, where the word common seems to be inherently understood as something obliged and insisted by the crown. In the edsöresbalken instead, the spatial dimensions of the road were brought forward in the context of the sworn peace of the realm, where the judicial space produced by the traveller was considered as a product of the road and the actual motives of travelling of the individual using it. The analysis of the respective chapters and decrees of the code shows that, from the point of normative legislation, the road was not only a recognizable space of its own but also constituted a judicial condition capable of producing distinctive social implications for those involved in the maintenance and use of roads in medieval Finland.  相似文献   

5.
The medieval road system of England and Wales has never been studied in any detail. This article attempts to bring together the cartographic evidence of the Gough and Paris maps and the more indirect evidence of three royal itineraries. This will suggest first which Roman roads were still in use in medieval times, and second what new lines of travel had come into use, thus distinguishing between the paved Roman roads which were still usable and the new routes which made and maintained themselves.  相似文献   

6.
西宁至拉萨道路是青海地区交通网中的主线,近代西宁至拉萨道路(青海段)分布格局的变迁代表了青海地区历史时期道路分布格局变迁的一般规律。基于中国国家图书馆所藏1935年《青海省三十万分一图》的数字化成果,结合其他时期的资料可复原出清初至1954年近三百年青海地区西宁至拉萨道路分布格局的变迁过程。驿站制度裁撤导致的清代官道系统崩溃,新式交通工具带来的新交通体系和民国时期青海地区的开发活动是近代青海地区道路分布格局变迁的三大驱动力。清至民国西宁至拉萨道路(青海段)分布格局的变迁,表现出历史时期复杂地形条件下道路分布格局易受多变的人文要素影响的特点。基于丰富实测地图资料的近代道路复原是准确复原古代道路的基础。  相似文献   

7.
This paper argues that the spatial scope of agglomeration economies is more complex than is often assumed in the literature. We provide insight into this issue by showing that agglomeration on short distances (<5 km) does not significantly affect wages, whereas it has a significant and positive effect on medium distances (5–10 km). This effect attenuates rapidly across geographic space, becoming insignificant after 40–80 km. We offer several explanations for this observed distance decay pattern. The results do not imply, however, that nearby agglomeration is irrelevant to the wage formation: only highly urbanized areas benefit from agglomeration on longer distances. Furthermore, this article finds no evidence that foreign economic mass affects wages in the Netherlands, which suggests that national borders are still a substantial barrier for economic interaction.  相似文献   

8.
Geographers working in mountainous northern Pakistan note that gains in accessibility following the Karakoram Highway's official opening in 1978 significantly reshaped social organization, economic activity, and land use across the region. These valuable regional‐scale analyses provide few insights regarding the contingent and variable ways new roads are conceived and experienced at the community and household level by the people whose mobility they drastically impact. This article addresses that limitation of regional research by focusing on an individual agricultural community called Shimshal that in 2003 completed a 40‐kilometre link‐road connecting it to the highway. Drawing from qualitative information gathered before and after the Shimshal road's completion, we briefly describe the community's motivation for constructing the road, villagers’ accessibility‐related hopes and concerns as it was being built, and some of the social, cultural, and economic changes that followed the road's completion. The article concludes by summarizing the community's response so far to landslide‐induced destruction of over 20 kilometres of the Karakoram Highway which, since January 2010, has left community members without vehicular access to the rest of Pakistan just seven years after their link‐road's completion.  相似文献   

9.
Explaining how the monumental statues (moai) of Easter Island were transported has remained open to debate and speculation, including their resource expenditures and role in deforestation. Archaeological evidence including analysis of moai variability, particularly those abandoned along ancient roads, indicates transport was achieved in a vertical position. To test this proposition we constructed a precise three-dimensional 4.35 metric ton replica of an actual statue and demonstrate how positioning the center of mass allowed it to fall forward and rock from side to side causing it to ‘walk.’ Our experiments reveal how the statue form was engineered for efficient transport by a small number of individuals.  相似文献   

10.
The objective of this paper is to present statistical methods for evaluating the geometrical hierarchy of a network in comparison with a random hierarchy network. First, the random hierarchy network is explicitly formulated by four stochastic processes in which line segments or lines, which represent roads, are randomly placed and their placement is independent of their ranks. Second, under these stochastic processes, this paper derives the expected value and variance of i) the number of intersections between roads of different ranks; and ii) the distance from an arbitrary point to the nearest highest-ranked road through two kinds of routes. Using these expected values, the intersection index and the detour index are proposed, and it is shown that these indicators are useful for evaluating the geometrical hierarchy of a network. As calculation of these indices is laborious, an efficient computational method is developed, and its application to an actual example is described.  相似文献   

11.
乡村地区路网通达性研究——以陕西省丹凤县为例   总被引:2,自引:0,他引:2  
通达性是指交通网络中各节点相互作用的机会大小,也是从出发地前往目的地的方便程度。道路网络是支撑乡村地区经济社会发展的基础,而通达性则是反映道路网络水平和质量的有效评价指标。本文以位于陕西秦巴山区的丹凤县为例,基于第二次土地利用现状调查和实际考察资料,分别以乡镇和行政村为单元,以GIS方法为支撑,采用道路临近性、乡镇内部可达性和道路衔接性三项指标,分析和评价了丹凤县乡村地区路网通达性。本研究对陕南秦巴山区乡村路网建设和移民搬迁工程有一定指导作用,对乡村地区路网通达性分析和评价方法进行了有效改进。  相似文献   

12.
Bolivia's rate of deforestation throughout the 1990s was among the most rapid anywhere in the Amazon Basin. This drastic clearing stood in sharp contrast to the relatively slow rates of landscape change that had prevailed in previous decades. This article reviews the models used for explaining deforestation, and argues that the new context of globalization, structural adjustment, regional integration and rapid technological change contributed to accelerated forest cutting during the 1990s. The author suggests that many environmental policy approaches developed during the 1970s and 1980s no longer address the current clearing situation effectively, and that today's frontiers differ profoundly from previous ones. The widely held idea that intensive production per se reduces forest destruction may not be valid on tropical agro‐industrial frontiers, such as the soybean zones of Bolivia and Brazil.  相似文献   

13.
Next to agriculture, road development is one of the most significant sources of stress to wetlands in Prairie Canada. However, there currently exists limited guidance for incorporating direct, indirect, and induced effects to wetlands in impact assessment and mitigation planning for small and often routine developments, including access roads or highway improvement initiatives. Based on the Louis Riel Trail, Highway 11 North twinning project in Saskatchewan, Canada, this article demonstrates a methodological approach and decision support framework for assessing and managing direct, indirect, and induced effects to wetlands from linear developments. No regulatory‐based environmental assessment was required for the highway project; effects were deemed to be insignificant under current wetland mitigation practices. However, our results show that 1115 ha of potentially affected wetlands are located within a 500 m impact zone on either side of the proposed highway. More than 50 percent of these wetlands are seasonal, less than 1 ha in size, and typically not included in mitigation planning. An expert‐based multi‐criteria evaluation of impact and mitigation options for wetlands in the study area indicated “no net loss” as a planning priority, and a preference for a spatially ambitious mitigation plan focused on direct, indirect, and potentially induced impacts. In practice, however, mitigation is often restrictive, focused on mitigating only direct impacts within the project's right‐of‐way, in this case less than 50 ha of wetlands, resulting in the potential for significant net loss of wetland habitat and function. If the risk to wetlands is to be given due consideration in project planning and development for roads and road improvement initiatives, then structured assessment methods and decision support frameworks should be sensitive to the time and resource constraints of small projects and screening‐type assessments. This requires also that wetland mitigation policies are developed and implementation plans formulated as part of project planning and assessment initiatives for linear developments.  相似文献   

14.
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This paper has two aims: to explore approaches to the measurement of children's daily travel to school in a context of limited geospatial data availability and to provide data regarding school choice and distance travelled to school in Soweto-Johannesburg, South Africa. The paper makes use of data from the Birth to Twenty cohort study (n?=?1428) to explore three different approaches to estimating school choice and travel to school. First, straight-line distance between home and school is calculated. Second, census geography is used to determine whether a child's home and school fall in the same area. Third, distance data are used to determine whether a child attends the nearest school. Each of these approaches highlights a different aspect of mobility, and all provide valuable data. Overall, primary-school-aged children in Soweto-Johannesburg are shown to be travelling substantial distances to school on a daily basis. Over a third travel more than 3 km one way to school, 60% attend schools outside of the suburb in which they live, and only 18% attend their nearest school. These data provide evidence for high levels of school choice in Johannesburg-Soweto, and that families and children are making substantial investments in pursuit of high-quality educational opportunities. Additionally, these data suggest that two patterns of school choice are evident: one pattern involving travel of substantial distances and requiring a higher level of financial investment and a second pattern involving choice between more local schools, requiring less travel and a more limited financial investment.  相似文献   

16.
Abstract

Backfill material from a 12th- to13th-century quarry, north of Wallingford, south Oxfordshire, comprises sandy loam overlain by Cretaceous (early Cenomanian; Mantelliceras mantelli Macrofaunal Biozone) Glauconitic Marl Member, of the West Melbury Marly Chalk Formation as identified by its abundant, biostratigraphically useful, foraminifera and ostracods. A local outcrop source of the Glauconitic Marl Member, less than 1 km north of the quarry pit, is the likely provenance of this material, and a contemporaneous road, which was discovered adjacent to the medieval quarry by magnetometer surveys and archaeological excavation, would have aided its transportation, into the town via the North Gate. We hypothesise that the use of a calcareous marl to overlay sandy loam deposits probably encouraged land restoration when the quarried area was returned to pastoral agriculture.  相似文献   

17.
Abstract

Stonehenge in the UK is one of the best-known and most important archaeological sites in the world. Unfortunately the site suffers considerable intrusion in the form of two busy roads which pass close by on either side of the stone circle, which provide an ‘excellent’ view of the site in its landscape. It is not a priori certain that closing one road and burying the other, as was proposed by those charged with managing the site, would actually improve social welfare.

A contingent valuation survey was undertaken, in which willingness to pay for the construction of a two kilometre tunnel for the A303 road where it passes Stonehenge, along with the closure and dismantling of the A344 road, was contrasted with willingness to pay to retain the current road layout. The survey was reinforced by means of computer-enhanced photographs and maps. The results of the survey indicate that while most respondents would prefer to retain the current scenario, most are not willing to pay to do this. Those who prefer the. construction of the tunnel seem far more financially committed. The net heritage benefit arising from the construction of the tunnel turns out to be £114 million.  相似文献   

18.
以广东省连州市为例,设计路网连通度、可达性、农村路网与干线路网衔接的平均距离三项指标来分析乡村地区公路网的通达性水平。结果显示,连州市路网的连通度较低,布局不完善,并存在明显的干线路网指向性特征;路网可达性水平总体不高,各乡镇内部联系的便捷度普遍较低,且呈现出同心圈层的结构;农村路网与干线路网的衔接较好,具有较强的集散功能。最后,通过计算指综合分值的方法,对连州市的农村路网通达性空间格局进行分析,根据综合得分将连州市12个乡镇分为5个等级,其中连州镇、东陂镇的通达性水平最高,通达性水平最低的是三水瑶族乡;并初步探讨了其背后的形成机理,认为农村路网的通达性水平是多种因素综合作用的结果,包括区域面积、地形状况、经济实力、结点布局、道路建设等。  相似文献   

19.
The MAP/WINE campaign has yielded information on small scale structure and turbulence in the winter mesosphere and lower thermosphere by a number of very different remote and in situ techniques. We have assimilated the data from the various sources and thus attempted to present a coherent picture of the small scale dynamics of the atmosphere between 60 and 100 km. We review physical mechanisms which could be responsible for the observed effects, such as ion density fluctuations, radar echoes and wind corners. Evidence has been found for the existence of dynamic structures extending over distances of the order of 100 km; these may be turbulent or non-turbulent. The results indicate that gravity wave saturation is a plausible mechanism for the creation of turbulence and that laminar flows, sharply defined in height and widespread horizontally, may exist.  相似文献   

20.
Roads have manifold social and environmental impacts, including regional development, social conflicts and habitat fragmentation. ‘Road ecology’ has emerged as an approach to evaluate the various ecological and hydrological impacts of roads. This article aims to complement road ecology by examining the socio‐spatial processes of road building itself. Focusing on the Brazilian Amazon, a heavily‐studied context due to forest fragmentation by roads, the authors consider non‐state social actors who build ‘unofficial roads’ for the purpose of gaining access to natural resources to support livelihoods and community development. They examine four case studies of roads with distinct histories in order to explain the socio‐spatial processes behind road building in terms of profit maximization, land tenure claims, co‐operative and conflictive political ecologies, and constraints as well as opportunities afforded by the biophysical environment. The study cases illustrate the need for a multi‐pronged theoretical approach to understanding road building, and call for more attention to the role of non‐state actors in road construction.  相似文献   

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