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1.
《Urban geography》2013,34(8):1163-1191
Although theoretical studies have contended that telecommuting could cause residential relocation to peripheral areas, empirical evidence regarding this argument is scant and inconclusive. Moreover, previous studies have given little consideration to telecommuters' job locations. Using data from the 2006 Seoul Metropolitan Area Household Travel Survey, this study investigates the relationships between telecommuting and residential location, considering job location. Regression results suggest that telecommuter households are indeed more likely to reside in outlying areas, consistent with theory. However, this does not necessarily mean that telecommuting facilitates living in outlying areas, nor, conversely, that long commutes stimulate telecommuting: causality cannot be established with these data. But contrary to both hypotheses, the result partially arises from the fact that firms allowing telecommuting also tend to be located in peripheral areas, with telecommuters having shorter commute distances compared to office workers. Consequently, issues regarding telesprawl need to be discussed considering the distribution of telecommuting-conducive occupations.  相似文献   

2.
In this paper we assess the ways in which the topography of glaciated northern Britain has affected the siting and operations of water mills, and compare those factors and mill locations for mills in unglaciated southern Britain. We then explore the impacts of these findings on the potential downstream impacts of mill dam failure.We used a GIS to plot the locations of all 1712 localities in Britain's Ordnance Survey Gazetteer that include “mill”, “milton” (‘milltown’) and “miln” in their name. We then examined the geomorphology of mill locations in two study areas, one in northeast Scotland (glaciated; 421 localities) and one in southern England (unglaciated; 438 localities), assessing (i) mill location within the drainage net, and (ii) the steepness of an adjacent stream within a radius of 500 m of the mill locality. The large majority of mills are located within the first 10 km of the drainage net in both study areas, presumably on relatively stable bedrock channels. The data for most of the mills in both study areas indicate that catchment areas of less than 200 km2 are sufficient to supply the water necessary for operation of a mill, but the higher rainfalls and runoff in Scotland (almost twice the values in the England study area) mean that mill dams in S England must have been higher and of higher capacity than those in NE Scotland. That finding is consistent with the results related to channel steepness, which show that mills in Scotland are associated with steeper channels than is the case in England. The generally greater channel steepness in Scotland (and the greater downstream extent of those steeper channels, as also confirmed by the data) reflect both the many glacially steepened bedrock channel reaches in Scotland and the steepening of Scotland's coastal bedrock channels as a result of glacio-isostatic rebound.The technical requirements of water mill operation favour situations where water can be delivered to the top of, or at least part-way up, the mill wheel. Scotland's steeper rivers and its higher rainfalls mean that Scotland's mills require smaller mill dams, if they are needed at all. It would therefore be expected that catastrophic or managed failure of mill dam walls in northern Britain would release lower volumes of trapped sediment to the downstream fluvial system. These lower volumes would in turn result in lower geomorphological impacts downstream of the dam, both in terms of changing channel patterns and burial of the bed. Such dam failure is a key current issue in geomorphology and one case study of a small failed mill dam in western Scotland confirms the minimal downstream impacts of that failure.  相似文献   

3.
When using rift lakes as proxies for palaeoclimate it is essential to know if water level changes are of geological or climatic origin, and whether a reinterpretation of palaeo-lake levels derived from lithostratigraphic sequences is required. The saline, endorheic Lake Beseka is located in the tectonically active Main Ethiopian Rift. Despite the aridity of the rift valley the lake's surface area quadrupled from 11.1 km2 in 1973 to 39.5 km2 in 2002. We quantify the lake growth by means of a detailed bathymetric model and high-resolution satellite time series. We analyse the potential climatic, anthropogenic, and tectonic agents of Lake Beseka's growth. Multitemporal remote sensing data and meteorological records were compared with in-situ measurements of hydrochemical parameters and water depth to address the reason for the lake level rise. Our results suggest that Lake Beseka's expansion originates from an increased discharge of the hot springs. The combined analysis of satellite data and in-situ measurements proved to be a valid tool for the quantification of lake level changes and can help to detect the causes of these variations.  相似文献   

4.
5.
Since the 1970s, protected area networks in mainland Southeast Asian countries have developed significantly to occupy 4–25 per cent of their respective national areas, located mostly in the mountainous domains of ethnic minority peoples. Through this process, regions that were only nominally part of national geobodies until the 1950s have become more territorially integrated. The complexity of the characteristics and geographical impacts of this territorialisation have yet to be grasped. As a step in this direction, we briefly outline a multilevel systems approach that usefully contextualizes these issues together with a historical and cartographical assessment of the evolution of protected area networks for Burma, Thailand, Laos, Cambodia and Vietnam. Our main findings are intertwined. On the one hand, protected areas represent a new tool of state intervention in mountainous areas, clearly in keeping with past, notably colonial, actions. On the other hand, this evolution in state territorialisation and attendant power relations have disrupted, far more deeply than previous actions, the pre‐1970s sociogeographical organization in mountainous areas, where most of the region's residual forests remain.  相似文献   

6.
The expansion of medium-sized cities in Brazil has increased significantly since the 80–90's decades. In that period, most of the urbanization process was represented by the agglomeration of the population in the major metropolitan areas such as São Paulo and Rio de Janeiro. Nowadays, the rural-urban movement in Brazil is predominantly affecting cities with less than 1 million inhabitants, located particularly in the Center-West and in the Semiarid Northeast regions. The city of Teresina, the capital and largest city of the Brazilian state of Piauí, is one example that has shown an accelerated process of urban development. In this context, this paper seeks to discuss the urban sprawl of Teresina over the last four decades (1974–2014), associating its trends of urban expansion and population growth with their social and environmental implications. The results of our work indicate that urban sprawl in Teresina has been continuous over the years and getting faster in the 2010–2014 period. High demographic density areas are located mostly in peripheral zones, where the low-income population dominates. The population density varies across the city, and it is far from the standard proposed by the urban legislation. Thus, urbanization in Teresina is characterized by the sprawl of its municipal boundaries, intra-urban densification and verticalization, and an increase in population, especially in areas of low-income neighborhoods.  相似文献   

7.
《Urban geography》2013,34(4):362-375
Recent studies have shown that (officially designated) poverty areas in large American cities have expanded geographically each decade since their inception in 1960. The territorial expansion of poverty areas in the 1970s was especially severe in Chicago, where new poverty-area growth exceeded the geographic extent of preexisting poverty areas. In the more recent decade of the 1980s, the expansion of Chicago's poverty areas slowed significantly. An analysis ofthis expansion process for Chicago, using 1970, 1980, and 1990 census data, illustrates that the movement of neighborhoods into and out of poverty is related to their previous poverty level, relative location, and rate of population loss. The recent slowdown in the geographic expansion of Chicago's poverty areas is highly correlated with the declining city-wide rate of population loss. Irrespective of this slowdown in territorial expansion, the residential function of Chicago's poverty areas is becoming increasingly obsolete as fewer and fewer people are residing in them.  相似文献   

8.
Residential segregation of ethnic groups is a major feature of cities in multi‐cultural societies such as New Zealand's. Measuring the degree of segregation has been the focus of much attention over the last half century, but there are difficulties with comparative studies using most of the measures adopted. An alternative procedure which classifies residential areas according to a homogeneity‐heterogeneity continuum is applied here to 1996 census small‐scale data for each of New Zealand's 33 main urban areas, to identify the degree of segregation of various ethnic groups. It reports that most New Zealanders from all ethnic groups (defined by self‐identity) live in mixed rather than exclusive residential areas. The main ethnic enclaves/ghettos are occupied by Maori and Pacific Islanders, and are entirely concentrated in the North Island, especially in urban areas which have substantial Polynesian populations.  相似文献   

9.
《Urban geography》2013,34(8):1100-1117
Metropolitan areas today are faced with pervasive changes of their urban spatial structure and are reshaped by postsuburbanization processes. In this study, one example of such postsuburban restructuring, the multinucleated monofunctional clustering of higher-order services, is investigated in the urban fringe of Vienna, Austria. The methodological framework uses microgeographic data for 2006 and applies a case-control point process modeling approach, which accounts for nonstationarity in first-order effects. The results show a relocation of highly specialized firms into the outer metropolitan ring, where these firms provide functional enrichment. This disagrees with the classical notion of a central place hierarchy. The urban fringe thus increasingly conforms to the core city. This spatial functional agglomeration shows statistically significant evidence of a bicentric urban structure, with the two new subcenters located in traditional suburban areas. Accordingly, Vienna's urban fringe is being altered by new postsuburban forms.  相似文献   

10.
11.
Several factors contribute to on-going challenges of spatial planning and urban policy in megacities, including rapid population shifts, less organized urban areas, and a lack of data with which to monitor urban growth and land use change. To support Mumbai's sustainable development, this research was conducted to examine past urban land use changes on the basis of remote sensing data collected between 1973 and 2010. An integrated Markov Chains–Cellular Automata (MC–CA) urban growth model was implemented to predict the city's expansion for the years 2020–2030. To consider the factors affecting urban growth, the MC–CA model was also connected to multi-criteria evaluation to generate transition probability maps. The results of the multi-temporal change detection show that the highest urban growth rates, 142% occurred between 1973 and 1990. In contrast, the growth rates decreased to 40% between 1990 and 2001 and decreased to 38% between 2001 and 2010. The areas most affected by this degradation were open land and croplands. The MC–CA model predicts that this trend will continue in the future. Compared to the reference year, 2010, increases in built-up areas of 26% by 2020 and 12% by 2030 are forecast. Strong evidence is provided for complex future urban growth, characterized by a mixture of growth patterns. The most pronounced of these is urban expansion toward the north along the main traffic infrastructure, linking the two currently non-affiliated main settlement ribbons. Additionally, urban infill developments are expected to emerge in the eastern areas, and these developments are expected to increase urban pressure.  相似文献   

12.
This study compared three hydrological methods – low flow frequency analysis, flow duration curve (FDC), and concentration-discharge (C-D) modeling – to determine the water requirement of the Gavkhuni wetland located in an arid region of Iran. Due to the effects of water impounding upstream on the hydrological regime of the Gavkhuni's inflow after construction of the Zayandehrud dam, none of the methods produced satisfactory results.Consequent modification of the hydrological regime of the wetland's inflow using a scaling process allowed all the methods except low flow frequency analysis to dependably estimate the base flow for the wetland. The results of the C–D method revealed that this method can provide a minimum health condition from the water quality point of view, while the results of the FDC demonstrated that not only the inflow estimated using this method can supply minimum conditions in terms of water quality parameters, but it also covers most areas of the wetland, based on the results of hydraulic modeling.The results reveal that the hydrological methods implemented in this study can dependably estimate environmental water allocation for wetlands in arid and semi-arid regions when there is no detailed knowledge about the biological requirements of the wetlands' biota.  相似文献   

13.
《Urban geography》2013,34(7):601-626
The commemoration of slain civil rights leader Martin Luther King Jr. (MLK) is a growing movement in many American cities and towns. School naming is an important yet underanalyzed part of this project. A recent struggle in Riverside, California over naming a high school for MLK is used as a springboard for: (1) conceptualizing school names as cultural arenas for debating student and community identity and (2) conducting a general study of the types of U.S. public schools named for King. As illustrated in California, school naming can be interpreted by one social group as a means of integrating and inspiring students historically and viewed by another group as a means of drawing boundaries around students in terms of race and local heritage. According to 1997-1998 data, 110 public schools bear King's name. They are located most often in the central cities of large and mid-size urban areas. King's name is most frequently found on schools that teach early and middle grades. Schools named for Martin Luther King do not necessarily denote a "Black" school in terms of the racial characteristics of students, although they do not fully integrate Whites with African Americans or Whites with minorities in general. Naming schools for King is part of a larger refashioning of the urban cultural landscape as racial and ethnic groups increasingly seek public recognition of their historical achievements.  相似文献   

14.
《Basin Research》2018,30(1):5-19
The Chatham Rise is located offshore of New Zealand's South Island. Vast areas of the Chatham Rise are covered in circular to elliptical seafloor depressions that appear to be forming through a bathymetrically controlled mechanism, as seafloor depressions 2–5 km in diameter are found in water depths of 800–1100 m. High‐resolution P‐Cable 3D seismic data were acquired in 2013 across one of these depressions. The seafloor depression is interpreted as a mounded contourite. Our data reveal several smaller buried depressions (<20–650 m diameter) beneath the mounded contourite that we interpret as paleo‐pockmarks. These pockmarks are underlain by a complex polygonal fault system that deforms the strata and an unusual conical feature results. We interpret the conical feature as a sediment remobilization structure based on the presence of stratified reflections within the feature, RMS amplitude values and lack of velocity anomaly that would indicate a nonsedimentary origin. The sediment remobilization structure, polygonal faults and paleo‐depressions are the indicators of the past subsurface fluid flow. We hypothesize that the pockmarks provided the necessary topographic roughness for the formation of the mounded contourites thus linking fluid expulsion and the deposition of contouritic drifts.  相似文献   

15.
《Urban geography》2013,34(4):327-347
Through a case study in a village located in suburban Haikou City, Hainan Province, this article suggests the existence of a local development regime that exercises illegal farmland conversion in China's urban periphery. This regime consists not only of state officials and business investors, but also of local farmers anxious for off-farm employment. Our study highlights the broad transitions that led to the rise of local development regimes in China's urban periphery. These transitions include (1) the development of the local state, (2) farmers' changing relations with local authorities, and (3) the asymmetrical liberalization of land transaction rights in rural and urban areas. Whereas the state government still manages to intervene in the local conversion of farmland, such intervention is increasingly ineffective as economic liberalization intensifies. A series of potential policies are recommended to protect farmland and agricultural livelihoods in the context of rapid urbanization.  相似文献   

16.
ABSTRACT. Farmers in Marin and Sonoma Counties, located north of San Francisco, are experimenting with numerous alternatives to California's widely known industrial dairy style. Many analysts suggest that consumer politics, food scares, and globalization explain such shifts to organic and other types of “quality” food production. While acknowledging the importance of these factors, we argue that the alternatives in this region are best understood as an outcome of broad‐based land‐conservation efforts developed through historical and ongoing struggles over urban growth, rising concerns about environmental values, and deep regional interests in dairy preservation. Over time, preservation of this agricultural landscape has contributed to the emergence of a quality food industry historically rooted in the region's politics of place.  相似文献   

17.
Shuttle Imaging Radar-A data are employed to study the settlement, population and land use in the Baoding and Dezhou areas of the North China Plain. By applying nearest neighbor and quadrat analyses, the settlements are found to exhibit a mixed random-clustering pattern which defied the application of Christaller's central place theory. The distinctly visible boundaries from the images permitted accurate estimation of population in both areas. The linear land use forms, notably transportation lines, could also be accurately mapped; the Chinese practice of lake reclamation was also revealed. It is concluded that SIR-A data are useful for much human geography research.  相似文献   

18.
Highly technological in vitro fertilization (IVF) treatment is available at relatively few medical centers in rural United States. This research derives a spatial accessibility surface for IVF centers in a rural Midwestern state through the application of computational methods that consider spatial and non-spatial parameters to discover potentially underserved areas in the state. These methods include a modified gravity model and techniques from spatial interaction modeling. The approach develops an enhanced accessibility index that incorporates three key sociodemographic variables describing patients seeking infertility healthcare in Iowa that have been identified based on a survey of IVF care practitioners in the state. Self-organizing map techniques are used to reveal cluster locations based on the degree of match between census sociodemographic data and the expert-identified variables. The spatial accessibility surface is combined with the sociodemographic clusters to define an enhanced measure of spatial accessibility. The results suggest that while the state's IVF centers are located in tracts characterized by high spatial accessibility, at least 19% of patients travel from census tracts classed as moderate to low accessibility. This result reveals some opportunities for service improvements for these locations. Interestingly, for tracts that are characterized as having a lower patient sociodemographic match, high spatial accessibility does not appear to be a factor that improves the likelihood of patient care, at least for the variables investigated as part of this research.  相似文献   

19.
将集群识别与空间分析相结合,通过全国集群模板识别产业集群,进而利用局部空间统计方法,探测产业集群的空间布局特征。利用2008年北京市和全国经济普查数据,从产业联系的角度识别了北京市制造业集群,在此基础上进一步测度了北京市制造业集群的空间分布现状与布局特征。研究发现,北京市制造业集群主要分布在近郊区并向远郊区延伸,资源条件、政策环境、交通区位、历史因素等多种区位因子均对集群的区位选择产生影响。从总体分布来看,北京市制造业集群的空间布局存在分布比较分散、功能重叠或与区县功能定位不符等问题。未来在政策制定时,应进一步强化北京市制造业集群的空间集聚,发挥区域产业政策的引导作用,并不断依托产业园区优化集群发展环境,引导符合区县功能定位的制造业集群发展。  相似文献   

20.
The tornado siren has become the standard method of notifying resident populations of dangerous weather conditions. In March, 2012, the city of San Marcos, Texas purchased 14 Tempest-121 rotating sirens creating a coverage network. Because San Marcos has experienced two tornadoes during the previous twelve years, two research questions were constructed, 1) what is the spatial coverage of the tornado siren network in San Marcos, and 2) what is the approximate number of residents located outside the siren's network coverage area? The hypothesis stated that the siren network left more than 10 percent of the population outside the coverage area.Each tornado siren was individually located and associated GPS data allowed for construction of the siren network in a GIS. The analysis identified approximately 26 percent (22 km2) of San Marcos located outside the network's coverage area. Furthermore, analysis of census block data and the extent of siren coverage resulted in 5.14 percent of residents not included in siren coverage, approximately half compared to what was hypothesized. As San Marcos continues to expand, both in size and in population, the question of whether there is enough coverage for the entire city for the foreseeable future remains unclear.  相似文献   

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