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1.
On-going tenure changes in the cotton zone in southern Mali are discussed. Land tenure in the area is changing and adapting to the rapid agricultural development taking place. This adaptation supports the main tenets of Property Rights Theory (PRT). The driving forces behind enclosure of land rights as described by PRT, such as population pressure and increased market access, are acknowledged. Enclosure takes two forms in the study area. First, some customary authorities in villages where population pressure is relatively high attempt to restrict access to pastures and woods on village land to create exclusive village commons. Second, holdings are being subdivided and farmers are increasingly confining their fields through tree planting. Except around the towns, where semi-formal land sales are becoming increasingly frequent, this individualisation does not imply exclusive and absolute private property to land. Bundles of overlapping rights still exist where various individuals or groups control access to different resources on the same piece of land. 相似文献
2.
Control data are critical for improving areal interpolation results. Remotely sensed imagery, road network, and parcels are the three most commonly used ancillary data for areal interpolation of population. Meanwhile, the open access geographic data generated by social networks is emerging as an alternative control data that can be related to the distribution of population. This study evaluates the effectiveness of geo-located night-time tweets data as ancillary information and its combination with the three commonly used ancillary datasets in intelligent areal interpolation. Due to the skewed Twitter user age, the other purpose of this study is to test the effect of age bias control data on estimation of different age group populations. Results suggest that geo-located tweets as single control data does not perform as well as the three other control layers for total population and all age-specific population groups. However, the noticeable enhancement effect of Twitter data on other control data, especially for age groups with a high percentage of Twitter users, suggests that it helps to better reflect population distribution by increasing variation in densities within a residential area delineated by other control data. 相似文献
3.
Using high resolution satellite imagery to estimate cropped area in Guatemala and Haiti 总被引：1，自引：0，他引：1
K. Grace G.J. Husak L. Harrison D. Pedreros J. Michaelsen 《Applied geography (Sevenoaks, England)》2012,32(2):433-440
Guatemala and Haiti are two of the most food insecure nations in the Western Hemisphere. Measurements of food availability and access are instrumental in developing targeted hunger reduction strategies yet no estimates of cropped area (a critical input in the calculation of food production) at either a national or sub-national-level exist. The purpose of this research is to produce estimates of cropped area for Guatemala and Haiti using an area frame sampling approach and very high resolution (∼1 m) satellite imagery. Related research has combined livelihood data with topographic information to construct cropped area estimates in other settings using generalized additive models. We expand this approach with the inclusion of specific population variables in place of the livelihood data. We produce estimates of cropped area for the two countries and sub-national units and our results highlight the significance and complexity of incorporating explicit population characteristics into models of cropped area. 相似文献
4.
Nathan Frey 《Urban geography》2017,38(10):1534-1549
This study examines equity issues in access to urban environmental amenities using Washington, D.C. as a case study. The amenities that are the focus of this study, urban trees and urban parks, have a range of social and health benefits for city dwellers, and Washington, D.C. is a major city with a large, diverse population and long-standing geographic divisions by race and class. Using spatial regression techniques, the study examines disparities in access to these amenities by race, ethnicity, and socioeconomic status at citywide and sub-city scales. Mixed evidence is found for disparities in access across amenities and across scales. The results emphasize the need for studies of access to urban environmental amenities to pay closer attention to the differences between amenities and to issues of scale. 相似文献
5.
中国人口收缩的城乡分异特征及形成机理 总被引：2，自引：0，他引：2
在县市尺度上对2000—2010年人口收缩区的城乡分异特征进行分析,划分出城增乡减型、城乡双收缩型和城减乡增型等类型,并建立人口收缩城乡分异的理论分析框架,探讨了不同类型的形成机理,主要的发现如下：① 2000—2010年,人口收缩单元占比约为38.6%,城增乡减型单元占据绝对主体,达到34.5%,而“城乡双收缩型”和“城减乡增型”单元占比均较低。② 中部地区人口收缩区城镇人口增长普遍较快,东北地区城乡双收缩的特征较为突出,而东部和西部地区存在较明显的空间分异。③ 城镇化水平和经济发展水平对人口收缩城乡分异特征的影响最为显著,城镇化水平较高而经济发展水平较低的人口收缩区越可能出现城镇人口增长缓慢甚至城乡双收缩。④ 经济发展速度、人口自然增长水平、公共服务等因素对人口收缩城乡分异特征也存在一定的影响。 相似文献
6.
Accessibility and land-use patterns at the forest fringe in the northeastern part of the Philippines 总被引：8，自引：0，他引：8
Accessibility is considered to be one of the most important determinants of use and land-cover change. In rural land-use change studies, the accessibility situation is often described by simple measures of the distance to a location of interest. In this paper, different measures of access are tested for a rural area at the forest fringe in the northeastern Philippines. The accessibility measures addressed range from simple distance measures to land-use type specific transport costs and a population potential measure. The different measures are tested based on their capacity to explain the spatial pattern of different land-use types. A comparison of the findings based on a spatial analysis and an analysis of household level data is made. It is concluded that the relation between land use and accessibility is dependent on the specific characteristics of the different land-use types. The (dis-)advantages of the use of the different accessibility measures are discussed. 相似文献
7.
In New Zealand, population change is interlinked with regional development. Places growing in population attract regional investment, while regional investment—or lack thereof—can change migration patterns. However, to determine the appropriate response to population change for a community, it is important to understand that population change involves much more than “just” migration. Specifically, it involves interactions between the three components of population change: natural change (births minus deaths), net migration (international and internal) and population ageing (changing cohort size). For example, migration can be negative, but growth can be positive due to underlying natural increase or growth in cohort size. Responses need to differ, depending on these drivers. The goal of this article is to provide new insights into these interactions using data for 275 cities, towns and rural centres (hereafter “urban places”) in New Zealand for the period 1976 to 2013. The results show that natural change has been consistently positive for most urban places up to the present, although projections indicate that in the future this component will become negative across much of the country. At the same time, net migration shows considerable spatial variation, not only in terms of volume, but also direction (negative or positive), which differs markedly by age. A net gain of people of retirement age can offset a net loss of young adults to deliver overall growth, and vice‐versa, but the two have very different implications for longer term growth. An analysis of the drivers of net migration using GIS and machine learning techniques provides an indication of the importance of economic conditions (land‐use and access to markets), lifestyle, access to essential services (hospitals and education) and their interaction with age in regional change. The results show that population age is the best predictor of migration. Younger people are moving to cities for tertiary education and work and older people near or in retirement are moving to smaller lifestyle towns but also want to be close to amenities such as hospitals and international airports. The research also shows that natural lifestyle characteristics (landscape and climate), in combination with age are just as important as economic conditions for understanding migration. Regional development, such as infrastructure that helps business (ports and services) is important for the working age population but not necessarily the retirement age group. When regional development, age/life‐cycle stage and lifestyle come together, such as in Queenstown and Tauranga, net migration gain is high. 相似文献
8.
Jacques Mourey Ludovic Ravanel Christophe Lambiel Joël Strecker Mattia Piccardi 《Norsk geografisk tidsskrift. Norwegian journal of geography》2019,73(4):215-228
ABSTRACTIn the European Alps, high mountain environments are subject to major impacts resulting from climate change, which strongly affect human activities such as mountaineering. The purpose of the study was to examine changes in access routes to 30 high mountain huts in the Western Alps since the 1990s. Data were derived from the use of two different methods, geo-historical studies and a questionnaire, and were used to identify both the climate-related processes affecting the climbing routes and the strategies implemented by public entities, Alpine clubs, guide companies, and hut keepers to maintain acceptable safety and technical conditions. The case studies revealed issues affecting three access routes and the results from the questionnaire showed that the main processes affecting access routes were loss of ice thickness and retreat from the front of the glaciated areas. Commonly, in situ equipment was installed to facilitate access for mountaineers and/or a part of a route was relocated to a safer area. The authors conclude that in most cases, the measures were effective but they were limited by financial, ethical and legal issues, especially in protected or classified areas that could jeopardise their durability and effectiveness. 相似文献
9.
基于公平最大化目标的2020年北京市养老设施布局优化 总被引：3，自引：1，他引：2
北京市正快速步入老龄化社会,机构养老作为一种重要的养老模式,对其布局公平性和合理性的研究具有重要的科学和现实意义。本文首先预测了自然增长状态下2020年北京市老龄人口的空间分布,然后建立设施布局优化模型,该模型以各需求点到养老设施的可达性差异最小化为目标;并采用粒子群优化算法求解,对北京市养老设施进行以公平最大化为目标的布局优化。研究结果表明,在公平最大化的目标下,首都功能核心区和城市功能拓展区(即中心城区)所提供的机构养老资源不能完全满足本地需求。城市发展新区在满足当地的机构养老需求之外,还将为中心城区提供大量机构养老服务,生态涵养发展区在满足本地需求的基础上还可为其他地区提供少量机构养老服务。该布局导向与《北京市养老设施专项规划》提出的布局建议相一致,且符合中心城区用地紧张、郊区自然环境较舒适的现实情况。研究结果能为养老政策的制定提供科学建议,所采用的方法也能为其他类型公共服务设施的布局优化提供借鉴。 相似文献
10.
Measures of geographic food access overlook an important source of statistical biases, termed the edge effect. The edge effect refers to the fallacy that events contributing to the spatial pattern of an analysis unit may be outside of that unit; thus merely summarizing events within the unit may lead to distortion of the estimation. Food procurement activities can happen beyond existing administrative boundaries. Delineating food access using unit-based metrics may misrepresent the true space within which food stores are accessible. To overcome this problem, this paper proposes a gravity-based accessibility measure to improve unit-based statistical approaches in food access research. In addition, this method accounts for the spatial interaction between food supply (e.g., food items in stock) and demand (e.g., population) as well as how this interaction is mediated by the spatiotemporal separation (e.g., travel time, modality). The method is applied to the case of Franklin County, OH and has revealed the food access inequity for African Americans by modes of transport, including walking, biking, and driving. The analysis of the correlation between mode-specific food access and socioeconomic status (SES) variables reveals that using a single modality in food access research may not fully capture the travel behavior and its relationship with local food environments. With modifications, the proposed method can help evaluate food access for a target population group, such as Supplemental Nutrition Assistance Program (SNAP) users or selected ethnic minorities who may face acute difficulties in procuring economically affordable and culturally appropriate foods. 相似文献
11.
The scope of empirical environmental justice (EJ) research has expanded beyond hazards exposure to scrutinize social inequities in access to amenities, but no prior study has examined the EJ implications of public beach access. Furthermore, quantitative research on white privilege is very scarce. To address these knowledge gaps, our study examines racial/ethnic and socioeconomic inequities in access to public beaches in the Miami metropolitan statistical area, Florida. Public beach accessibility is modeled with an innovative geospatial approach that involves population weighted distances to beach access sites. To assess EJ implications of public beach access for various racial/ethnic and socioeconomically vulnerable groups, spatial regression models are estimated using census tract-level data. Results indicate that beaches are more accessible to neighborhoods with a higher proportion of non-Hispanic Whites, while neighborhoods with higher percentages of Hispanics and socioeconomically disadvantaged residents have limited access. This study demonstrates the importance of assessing white privilege and access to environmental amenities in EJ research to better understand social inequities. 相似文献
12.
Gopal B. Thapa 《Singapore journal of tropical geography》1998,19(1):71-91
Amidst the increasing concern about steadily depleting forests in Laos, this paper examines its causes and existing forest management systems in Sangthong District. Forests in Sangthong were virtually undisturbed until the early 1970s. Guided by customary law, a relatively small local population utilised the forest sustainably for food, fodder, wood fuel and construction materials. Subsequently the government effectively abolished customary law through the declaration of forests as state property and the sanctioning of logging. Logging was banned in the early 1990s but forest degradation continues as a result of ongoing logging, the open access to forests, the government policy of utilising degraded forests for agriculture, and population pressure from in-migration. Village surveys show that local people appreciate ecological and economic values of forest resources and are willing to contribute to their management. These social qualities lay the foundation of a sustainable forest management system, but the evolution of this type of system has been prevented by the "open access" to forest resources. For effective forest conservation a management strategy focused on property rights reform, public participation and integrated rural development is proposed. 相似文献
13.
医疗设施可达性空间差异及其影响因素——基于上海市户籍与流动人口的对比 总被引：6，自引：4，他引：2
医疗设施可达性关乎民生健康、生活质量和社会公平等重大社会议题,受到广泛关注。将空间视角和社会视角相结合,考虑流动人口和户籍人口在城市不同区域内可达性的差异,将有助于更加全面地反映当前城市医疗服务的资源配置及其社会公平问题。本文以上海市不同等级医疗设施的可达性为研究对象,利用改进潜能模型和多元线性回归模型,分析了城市中不同区域内医疗设施的可达性、户籍人口和流动人口就医可达性差异及其影响机理。研究发现：医疗设施可达性自内城区向郊区逐渐降低,郊区可达性的波动程度较大;户籍人口的就医可达性优于流动人口,2类人群的差异在中心城边缘区和近郊区最为明显;居住地区位显著影响居民的就医可达性,但对于户籍人口的影响更加显著。本文可为上海市医疗资源的空间配置优化和改善流动人口就医条件提供实证研究依据。 相似文献
14.
The variations of breast cancer mortality rates from place to place reflect both underlying differences in breast cancer prevalence and differences in diagnosis and treatment that affect the risk of death. This article examines the role of access to health care in explaining the variation of late-stage diagnosis of breast cancer. We use cancer registry data for the state of Illinois by zip code to investigate spatial variation in late diagnosis. Geographic information systems and spatial analysis methods are used to create detailed measures of spatial access to health care such as convenience of visiting primary care physicians and travel time from the nearest mammography facility. The effects of spatial access, in combination with the influences of socioeconomic factors, on late-stage breast cancer diagnosis are assessed using statistical methods. The results suggest that for breast cancer, poor geographical access to primary health care significantly increases the risk of late diagnosis for persons living outside the city of Chicago. Disadvantaged population groups including those with low income and racial and ethnic minorities tend to experience high rates of late diagnosis. In Illinois, poor spatial access to primary health care is more strongly associated with late diagnosis than is spatial access to mammography. This suggests the importance of primary care physicians as gatekeepers in early breast cancer detection. 相似文献
15.
未来情景下中国高温的人口暴露度变化及影响因素研究 总被引：3，自引：0，他引：3
基于RCP 8.5气候情景下21个高分辨率全球气候模式的日最高气温数据和A2r社会经济发展情景下的人口数据,以高温日数和人口数量的乘积构建高温的人口暴露度指标,采用多个气候模式集合平均的方法从网格单元尺度分析未来不同时段中国高温和强危害性高温的人口暴露度变化,并从全国和气象地理分区两种空间尺度研究人口暴露度变化的影响因素。研究表明：未来情景下,中国高温的人口暴露度明显增加,2021-2040年、2041-2060年、2061-2080年和2081-2100年相比基准时段1981-2010年分别增加了1.3、2.0、3.6和5.9倍,强危害性高温的人口暴露度增加更为显著,相比基准时段分别增加了2.0、8.3、24.2和82.7倍。高温的人口暴露度在华北、黄淮、华南、江南、江淮、西南和江汉地区增加较为明显,其中华北、黄淮、华南和江南最为显著;强危害性高温的人口暴露度在华北、黄淮、江南、江淮、西南和江汉等区域增加较为明显,其中华北、黄淮、江南和江淮最为显著;未来情景下人口暴露度的变化主要受气候因子的影响,其次受人口和气候因子的共同影响,单独人口因子的影响很小。全国尺度上,气候因子对未来不同时段人口暴露度变化的影响逐渐减弱,贡献率由70.0%左右逐渐减至60.0%左右。人口和气候因子的共同作用逐渐增强,贡献率由20.0%左右逐渐增至40.0%左右。 相似文献
16.
Thet1'onessofpopulationasbotl1producerandconsumerdetennjneshlatpopulahontakesaveryDimportanposih0nintheregionalsoci0ec0n0ndcdevelopmenLThecontradichonbetWeenp0pulationandwater,land,envirnmentandeconondcdevel0pmentistheInainoneintheregi0ItalPREDSystem.ThoughtheQaihoBasinhasvastexpanseoftenainandabundantresources,thet0ughnaedcondihonsofdryandcoldcllInaelllmakesitveryhardforhumanliving.Meanwhile,theecon0ndcdevelopmentmodedsgres0urcesexPloitahonaspriorityrequiresasultablegr0wthrateofp0pulaho… 相似文献
17.
代表性人口空间分布数据集的精度评价——以2010年广东省为例 总被引：1，自引：0，他引：1
以人口密度差异显著的广东省为研究区,比较Worldpop、GPW v4和2种中国公里网格人口分布数据集的空间分布一致性,并以第六次全国人口普查数据为真值,按人口密度分为高、中、低3组,从误差的数值分布和空间分布两方面定量评价4种数据集的精度,最后讨论估算误差的可能来源及数据适用性。结果表明,4种网格人口数据集中Worldpop整体精度最高,且在人口密集区的精度也是最高;GPW v4在低人口密度和中人口密度区域精度略高于Worldpop,但对镇街内人口分布细节刻画不够详细;2种中国公里网格人口分布数据集精度较前两者低,主要受空间化方法和模型变量的选择所限制。Worldpop适合用于人口密度中等及人口密度高区域的精细化研究,GPW v4适合用于长时序、最小研究单元大于镇街的研究,第一种中国公里网格人口分布数据集适合用于需要考虑镇街内人口分布和空间异质性的研究,第二种中国公里网格人口分布数据集适用于需要考虑人口分布细节和空间格局变化的长时序研究。 相似文献
18.
基于CMIP5的逐日最高温度模拟资料、GGI情景数据库逐年代人口数据,在RCP4.5情景下,以对应栅格高温日数与人口数量的乘积作为人口对高温的暴露度指标,通过多模式集合平均预估未来中国人口对不同强度高温的暴露度变化。结果表明：相比于基准时段（1981-2010年）,中国人口对高温和强危害性高温的暴露度从2021-2040年开始明显增加,至2081-2100年暴露度分别增加了5.7倍和17.5倍;除了中国西部部分地区外,全国大部地区人群均受高温的影响,在21世纪中后期中东部大部人口对高温的暴露度超过10.0×106人?d;相比基准时段,随着年代的增长,中国人口对强危害性高温的暴露度在范围和强度上均有明显增加;2081-2100年,人口对高温和强危害性高温的暴露度增幅减缓。从气象地理区域上看,未来各时段人口对高温、强危害性高温的暴露度均有一定程度增加,但增加明显的区域主要集中在华北、黄淮、江南和江淮地区,华南地区对强危害性高温的暴露度增幅较小。高温日数变化对全国人口对高温暴露度的变化所产生的作用最明显。多模式集合的预估结果可以为防控未来高温风险提供重要的参考价值。 相似文献
19.
轨道交通已经成为塑造城市空间结构、组织公共生活的重要手段。在追求线网效率与形态等技术目标的基础上，轨道交通线网布局也越发有必要引入协同性、公平性等理念，寻求轨道交通与城市其他系统在空间上的协同发展，促进公共服务设施依托轨道交通实现公平共享。文章以深圳为案例，采用改进的两步移动搜索法，建构了休闲设施轨道交通可达性模型；按照深圳市轨道交通建设二期（至2011年）、三期第一阶段（至2016年）及三期第二阶段（至2020年）来划分，使用空间可视化、洛伦兹曲线等方法，评估了上述3个不同时段下轨道交通网络与休闲服务设施的耦合关系，比较了轨道交通网络对于休闲服务设施服务人口和空间覆盖面等层面的差异性。研究表明：深圳市轨道交通建设持续提升了城市核心区域休闲设施的轨道交通可达性，外围地区休闲设施轨道交通可达性则经历了先减后增的变化过程。轨道交通建设对于休闲服务设施有显著的空间效应及人口效应，深圳轨道交通可达性前50%的社区约占全市总面积的25%并覆盖全市总人口的40%。研究认为，深圳市乃至其他城市的轨道交通布局应更注重与休闲设施及人口的空间分布进行匹配，重点关注新兴人口增长的区域以及休闲设施资源充裕的区域，促进轨道交通与休闲服务设施协同布局。 相似文献
20.
"泛珠三角"产业、人口分布空间变动的趋势分析 总被引：3，自引：2，他引：1
随着地区经济一体化的发展,“泛珠三角”区域的经济格地理局将会出现不同程度的变化。当前“泛珠三角”区域一体化处于中期发展阶段,主要表现为产业和人口向“珠三角”集中。今后随着一体化的进一步发展,产业和人口将具有集中与扩散同时发生的特征,各地区形成特定产业和人口集中的专门化生产的地理格局。 相似文献