首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
美国荒野风景河流体系是全球最早建立的河流保护地类型。经过50年发展,其完善的体系呈现出一定空间分布特征。将线状国家荒野风景河流(NWSR)抽象为点状单元,对208个NWSR单元进行空间计算,并与自然生态和社会经济等因素进行叠加分析。结果表明,美国已有40个州分布NWSR,其中以俄勒冈等3个州的数量分布最多,且集中分布于特定的区域:西部的太平洋海岸、落基山脉和山间高地3个自然地理区;极地、温湿润、干旱3个Ⅰ级生态区;太平洋西北部、加利福尼亚、阿拉斯加及五大湖4个流域。NWSR线密度与州域的人口密度、经济水平相关性不强,但与大坝建设密切相关。荒野思想影响了法案制定,法案指导了遴选标准,遴选标准又进一步影响了NWSR的空间分布。研究对中国的借鉴意义在于:应当明确保护地指导思想、关注价值突出区域、确定合适遴选标准、重视保护地系统规划等。  相似文献   

2.
All systems have causes and effects that can be appreciated at different spatial scales. Understanding and representing the complexity of multi‐scale patterns in maps and spatial models are key research objectives. We describe the use of three types of correlation analyses: (1) a standard Pearson correlation coefficient, (2) a ‘global’ multi‐scale correlation, and (3) local geographically weighted correlation. These methods were applied to topographic and vegetation indices in a small catchment in Honduras that is representative of the country's hillsides agro‐ecosystem which suffers from severe environmental degradation due to land‐use decisions that lead to deforestation, overgrazing, and unsustainable agricultural. If the geographical scale at which topography matters for land‐use allocation can be determined, then integration of knowledge systems can be focused. Our preliminary results show that: (1) single‐scale correlations do not adequately represent the relationship between NDVI and topographic indices; (2) peaks in the global multi‐scale correlations in agricultural areas coincided with the median farm size, but there was no evidence of any community or larger‐scale land‐use planning or optimization; and (3) local multi‐scale correlations varied considerably from the global results at all scales, and these variations have a strong spatial structure which may indicate local optimization of land use.  相似文献   

3.
Academic study of the relationships between geography and religion constitutes a long‐established subfield of cultural geography. The tradition is particularly strong in the United States where the seminal work of the Berkeley School stimulated a wealth of research on mapping the religious landscapes of North America. Religion has received far less attention within British human geography, due, in part, to the marginal position of religion within cultural geography and, in particular, to the absence of reliable, comprehensive data on religious affiliation. The present research overcomes these ideological and methodological obstacles to advance knowledge of the geography of religion in the United Kingdom. Employing data from the latest Census of Population, embedded within an established tradition of mapping geographies of religion, the research provides detailed analysis of the geography of religious affiliation in Scotland at the advent of the twenty‐first century.  相似文献   

4.
随着文化创意产业在世界范围内的崛起,城市文化职能和全球文化城市成为城市网络研究的新兴视角。借助“大麦网”数据,基于空间分析和岭回归方法,揭示基于文化演出消费活动的中国城市网络空间结构与影响因素,对现有城市网络研究形成补充。研究表明:①文化巡回演出的城市网络呈现出中国城市网络中常见的“菱形结构”,但是向二、三线城市渗透的趋势较为明显,体现了不同级别城市本地文化生产能力的差异以及文化演出边际收益递增的特点;②中西部省会城市在城市网络中的影响力表现出明显的上升,而东部沿海地区核心城市的影响力则出现一定程度的下降,反映出中国不同地区演出市场发育程度以及区域中心城市在对外文化联系中地位的差异;③不同类型文化演出在空间分布和网络结构上同样存在较为明显的差异,反映出其市场结构和盈利模式的差异以及城市地方文化消费特征的影响;④文化教育发展水平、地方政府投入、城市总体经济发展和消费水平以及对外开放程度是影响中国文化演出消费城市网络空间格局的重要因素,反映出文化演出消费的独特性。  相似文献   

5.
The major patterns of biostratigraphical and geochemical change detected in a multidisciplinary study on recent environmental change and atmospheric contamination on Svalbard are summarised and synthesised. The patterns discussed are changes in sediment accumulation rates, organic matter accumulation rates, atmospheric contaminants, and biological assemblages (diatoms, chrysophyte cysts, chironomids). Possible environmental factors that may have influenced these patterns are discussed, in particular, the role of atmospheric contamination (including the deposition of nitrogen-compounds), local human impact, and recent climatic change. The major conclusions are (1) sediment accumulation rates show consistent temporal and geographical patterns with rates increasing towards the present-day and highest in the south, (2) sediment organic-matter accumulation rates increase markedly in the last 50–100 years, (3) atmospheric contamination is a combination of local and regional sources, (4) sediment inorganic geochemistry suggests catchment and lake responses to climate change in the last 30–50 years, (5) all lakes show a marked increase in the rate of biotic compositional changes in the last 50–100 years, and (6) Svalbard lakes appear to be highly dynamic and show considerable biotic and sedimentary changes in recent decades. The most likely cause of many of the observed changes is recent climatic change, with some local human activity at one site. Detailed interpretation of the observed changes is problematic given current limited knowledge about high Arctic limnology, biology, and catchment processes.  相似文献   

6.
《The Journal of geography》2012,111(4):204-212
Abstract

A series of computer-generated maps are presented, illustrating the state-level distribution of major crimes in the United States for the year 1968. The maps are divided into two broad groups—those relating to (a) crimes of violence, and (b) crimes against property. In the violent crime group, distributions are shown for murder, rape, robbery, and assault. The dominance of the South in terms of homicide is particularly striking. Burglary, larceny over fifty dollars, and auto theft are the property crimes represented. Western states, and various highly metropolitan states (such as New York) generally exhibit the highest property crime rates. Summary tables show the states with extreme (high or low) crime rates. States with the lowest rates generally lack large metropolitan nodes, while the converse is true, with California, New York, and Maryland heading the list of states with high rates in multiple crime categories.  相似文献   

7.
The age patterns of U.S. internal migration, while examined extensively at the national level, have not been fully explored at the regional scale. This study examines, using 1985 ‐ 1990 census data, the state‐level variations in two aspects of lifecycle mobility: the mobility level, or the average number of moves made over the lifecycle, and the mobility timing, or the age at which half the lifetime moves are completed. It further delineates typologies of states based upon their age structure of mobility. The study found that regional patterns in the mobility level showed some evidence of the Snowbelt‐Sunbelt patterns that characterized economic restructuring in the 1980s. Geographic patterns of mobility timing were less clear; however states in the West and the South showed somewhat more young distributions than the other regions. Further, there was a statistically significant relationship between mobility levels and timing: states with higher mobility levels also exhibited older mobility profiles, as a consequence of disproportionately high elderly mobility rates. The study highlights the regional differences in mobility behavior, and the interplay between the “how much” and the “when” of mobility.  相似文献   

8.
ABSTRACT. In the late 1980s more than 1 million Brazilians left Brazil without returning. Today an estimated 2 million Brazilians live abroad, 1.2 million of them in the United States. In this article I show that Brazilians migrate for a variety of reasons, including the geographical imagination. Why are so many Brazilians leaving for the United States? What are their geographical imaginations, and how are they described in their migration process? Using primary and secondary data and multiple methods, I address these questions by providing insights into Brazilian migrants' place perceptions, experiences, and reasons for migrating, focusing on the geographical imagination. Those migrants who end up returning to Brazil are more likely to cite financial and curiosity reasons for having migrated. A web of transnational religious and social networks sustains those immigrants who remain in the United States. Reasons for migrating are not economic alone; rather, they are based on interrelated and complex factors that range from adventure to curiosity, the cultural influence of the United States, family members, education, and escape.  相似文献   

9.
姜璐  邢冉  陈兴鹏  薛冰 《地理科学》2020,40(3):447-454
农村能源转型是能源消费革命的重要组成部分。基于问卷调查和入户访谈,对青海省10个县(区)的318户农区家庭用能信息进行调查,辨识了青海省农区不同收入分层家庭的能源消费模式,并通过建立典型家庭能源流模型,总结了家庭能获取-消费-废弃过程的形态变化。结果显示:青海省农区家庭能源消费以煤炭、薪柴和秸秆为主,非商品能源消费占比为49.6%,清洁能源使用率低。煤炭消费在5类家庭中均占比最高,薪柴和秸秆消费在低收入家庭占比较高。高收入家庭能源消费类型更多,消费量也大,能源流动更复杂。最后,根据青海省的经济地理特征,提出相应政策建议。  相似文献   

10.
加拿大入境美国旅游流的地域对接分析   总被引:1,自引:0,他引:1  
加拿大游客入境美国旅游是北美最大的国际旅游流。依据2006~2007年的有关统计资料,采用游客到访率、市场占有率和二维矩阵模型等,分析了加拿大10个省到美国22个州旅游流的0-D对接关系。结果发现:加拿大游客入境美国旅游,多以北部边界、五大湖区,沿环美高速铁路分东西两线流向美国南部;从加拿大各省到美国各州旅游流,遵循以"三择原理"为特征的0-D对接关系。其中,东部各省游客主要分布在五大湖区和东部沿海,中部各省游客分布在相邻的边界各州,西部各省游客主要分布在美国西部沿海,受趋"阳光性"影响沿环美高铁可抵达南部的佛罗里达。加拿大各省游客在美国各州的分布,主要受距离衰减原理、沿高铁和航空线分布、以及顶极旅游资源吸引的控制。这个研究拓展了旅游流0-D对接中的多源对多汇,为我国沿边省区与周边国家开展跨国旅游合作提供借鉴。  相似文献   

11.
Edward Jarvis in 1850 first demonstrated that admission rates to mental hospitals decrease with increasing residential distance, a relationship known today as “Jarvis's Law.” His original data are presented, mapped, and examined by regression analysis to better understand spatial and temporal patterns of mid-19th century mental hospital utilization. Distance substantially affected admission rates to a radius of about 60 miles from the institution in Massachusetts; and there was strong distance decay in the other states examined. For all twelve states, there was a positive association between age of the hospitals and admission rates, which also decreased with increasing residential distance.  相似文献   

12.
Hukou and non-hukou migrations in China: comparisons and contrasts   总被引:3,自引:0,他引:3  
The household registration (hukou) system in China was studied using China's 1990 census 1% microdata and interprovincial migration studies. In doing this, the socioeconomic characteristics and geographical patterns of long-distance hukou and non-hukou migratory flows were compared before developing a framework of dual migration circuits. The framework uses a statistical model to evaluate migration rates in relation to both origin and destination variables. It was found that these two types of migrants shared some general demographic characteristics, but displayed substantial socioeconomic differences. The hukou migrants that tended to originate in urban areas had an extremely high share of college-educated people and were employed in higher skilled jobs, while non-hukou migrants were mostly from rural areas with much lower educational attainment. Hukou labor migrants tended to move through government and formal channels, while non-hukou migrants relied on their own, often informal, source of jobs. Furthermore, a difference as to the migration mechanisms between hukou and non-hukou migrants was noted. Non-hukou migration rate were tied positively to the migration stock, a process consistent with a networked migration hypothesis, while hukou migration rates were not. The rural labor migrants moved away from provinces of high population pressure to those with more favorable land/labor ratios, in line with neoclassical predictions. Hukou migration moved in the opposite direction, reflecting a different set of factors at work. The analysis indicates that the hukou system remained a relatively powerful institution in structuring migration in the 1980s.  相似文献   

13.
ABSTRACT. The geography of terrorism remains underexplored. By focusing on the spatial patterns of terrorist attacks, the settings and land uses in which attacks occur, and the methods used to perpetrate violence, this analysis helps build a theory of terrorism geography. Between 1 January 1997 and 11 September 2005, 178 terrorist incidents occurred in the United States. Analysis of these incidents suggests three insights. At the national scale, terrorism in the United States clustered in large urban areas, with regional differentiation of terrorist motives and targets. At the scale of individual attack sites, terrorist motivations pinpointed offices, clinics, and public spaces; right‐wing violence, military, government, and infrastructural targets; and religious terrorism, commercial and special land uses. At the scale of individual interactions, terrorists crossed paths with victims in various ways. For example, the 2001 anthrax‐attack letters and lone‐wolf terrorism created alternative intersections of perpetrators with victims.  相似文献   

14.
As two rising great powers, China and India have undergone similar development processes, but they also exhibit significant differences in development paths and patterns. The significant differences in political systems, economic systems, and developmental environment between the two countries have attracted great attention from scholars. This research focuses on the regional differences and spatial evolution processes in urbanization and urban systems between the two countries from a geographical perspective. Based on the demographic censuses of both countries and the urban population data from the United Nations, this paper systematically compared and analyzed the spatial characteristics of urbanization and urban systems in China and India using various methods including spatial analysis, parameter estimation, and nonparametric estimation. The results indicate that: (1) Since the 1990s, the regional differences in urbanization in China have transformed from south-north differences to coastal-inland differences, whereas the north-south differences in India have been stable. (2) In recent years, the correlation between population density and urbanization rate kept increasing in China, while such correlation has been decreasing in India. (3) The economic reform posed significantly different effects on the spatial evolution of the urban systems in the two countries. The economic reform changed the major driving force for urban development in China from geographical and historical factors to the spatial structure of the economic system. However, in India, the driving forces for urban development have always been geographical and historical factors, and the economic reform even decreased the effect of the spatial structure of the economic system on urban development.  相似文献   

15.
16.
王颖  刘航  陈晓红  宋云婷 《地理科学》2020,40(7):1150-1159
基于城乡系统关联耦合的概念内涵,以东北三省34个地级市为研究单元,采用2003—2017年的城、乡发展数据,运用灰色关联模型,对东北三省城乡关联的内部要素作用、城乡耦合时空特征以及城乡关联耦合地域类型进行研究。结果表明:东北三省历年城、乡各要素间关联度均在0.5以上,属于较高关联;城、乡子系统中对城乡关联耦合的强作用要素集中于城市系统的经济、空间领域以及乡村系统的经济领域,弱作用要素集中于城市系统的工业、社会领域与乡村系统的人口、社会领域;2003—2017年,东北三省城乡耦合度平均值由0.788下降至0.692,城乡相互作用趋于缓和、城乡协调适应性不断增强;东北三省城乡耦合度呈现“南低北高、南北差异日渐缩小、高值集中于各省经济落后区域、低值向四大中心城市极化”的空间格局;东北三省34个城市的城乡关联耦合演化可划分为高水平协调稳定型、高水平协调倒退型、较低水平协调倒退型、低水平与较低水平协调发展型、低水平与较低水平协调稳定型5种类型。  相似文献   

17.
As two rising great powers, China and India have undergone similar development processes, but they also exhibit significant differences in development paths and patterns. The significant differences in political systems, economic systems, and developmental environment between the two countries have attracted great attention from scholars. This research focuses on the regional differences and spatial evolution processes in urbanization and urban systems between the two countries from a geographical perspective. Based on the demographic censuses of both countries and the urban population data from the United Nations, this paper systematically compared and analyzed the spatial characteristics of urbanization and urban systems in China and India using various methods including spatial analysis, parameter estimation, and nonparametric estimation. The results indicate that:(1) Since the 1990 s, the regional differences in urbanization in China have transformed from south-north differences to coastal-inland differences, whereas the north-south differences in India have been stable.(2) In recent years, the correlation between population density and urbanization rate kept increasing in China, while such correlation has been decreasing in India.(3) The economic reform posed significantly different effects on the spatial evolution of the urban systems in the two countries. The economic reform changed the major driving force for urban development in China from geographical and historical factors to the spatial structure of the economic system. However, in India, the driving forces for urban development have always been geographical and historical factors, and the economic reform even decreased the effect of the spatial structure of the economic system on urban development.  相似文献   

18.
美国山地降水量垂直分布的研究   总被引:3,自引:1,他引:2  
孙安健 《地理研究》1989,8(1):32-39
根据美国西部山地资料,依据宏观地理因素和局地海拔高度因素从各种气候区域和不同纬度上选择典型坡地研究了降水的垂直分布规律。  相似文献   

19.

Edward Jarvis in 1850 first demonstrated that admission rates to mental hospitals decrease with increasing residential distance, a relationship known today as “Jarvis's Law.” His original data are presented, mapped, and examined by regression analysis to better understand spatial and temporal patterns of mid-19th century mental hospital utilization. Distance substantially affected admission rates to a radius of about 60 miles from the institution in Massachusetts; and there was strong distance decay in the other states examined. For all twelve states, there was a positive association between age of the hospitals and admission rates, which also decreased with increasing residential distance.  相似文献   

20.
The Plataforma Burgalesa is a partly exposed extensional forced fold system with an intermediate salt layer, which has developed along the southern portion of the Basque‐Cantabrian Basin from Malm to Early Cretaceous as part of the Bay of Biscay‐Pyrenean rift system. Relationships between syn‐ and pre‐rift strata of the supra‐salt cover sequence and distribution of intra‐cover second‐order faults are observed both along seismic sections and at the surface. These relationships indicate an along‐strike variability of the extensional structural style. After a short period of salt mobilization and forced folding, high slip rates in the central portion of the major basement faults have rapidly promoted brittle behaviour of the salt layer, preventing further salt mobilization and facilitating the propagation of the fault across the salt layer. In contrast, at the tip regions of basement faults, slower slip rates have facilitated ductile salt behaviour, ensuring its further evaporite evacuation, preventing fault propagation across the salt layer and, in essence, allowing for a long‐living forced folding process. Our results indicate the important effect of along‐strike variation in displacement and displacement rates in controlling evaporite behaviour in extensional basins. Amount of displacement and displacement rates are key factors controlling the propagation of basement faults across evaporite layers. In addition, growth strata patterns are recognized as a powerful tool for constraining the up‐dip propagation history of basement faults in extensional fault‐related fold systems with intermediate décollement levels.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号