格网邻域滤波在车载激光点云道路边线提取中的方法研究

结合城市车载激光扫描点云道路数据与地物点各自的特点和空间分布,用路面点云控制道路两侧地物点云进行滤波,从而实现道路路面点和地物点的分离,并根据城市道路中含有高出路面边缘的路缘石的结构特性设置阈值来提取路缘石,通过设置合适的格网及其邻域格网中点的密度特性进一步滤波路缘石,生成道路边线。     

基于改进邻域均值的全色影像水域提取

利用传统邻域均值法对全色影像水域进行提取时,所提取的水域边界精确度严重依赖于搜索窗口的大小。本文通过分析水域灰度特征以及提取边界不精确的原因,对方法进行针对性的改进:依据邻域各像素点与种子点的灰度差值分别对其赋予不同的灰度值,以处理后的邻域均值作为特征进行水域提取。实验结果表明:基于改进的邻域均值方法对遥感影像水域有较好的提取结果,提取精度较之改进前有明显改善。     

自然邻域支持下的空间同位模式挖掘方法

空间同位模式指频繁发生在邻近空间位置的事件集合,此类模式对于深入理解不同空间要素间的交互关系具有重要意义。空间同位模式挖掘的一个核心内容是空间要素邻近关系构建,然而现有方法在空间要素分布不均匀时难以准确地描述要素间的邻近关系,容易导致挖掘结果的遗漏或误判。为此,本文提出了一种基于自然邻域的空间同位模式挖掘方法。首先从同位模式的产生机理分析入手,过滤同位模式挖掘中的干扰要素;进而,从距离邻近性、密度变化一致性和关系紧密性的原则出发,自适应地构建空间要素实例的自然邻近关系;最后,以自然邻域为基础,基于图的连通性从整体到局部发现多层次同位模式。试验分析与比较发现,本文方法能够有效发现空间要素分布不均匀情况下的同位模式,而且降低了人为设置邻域参数对挖掘结果的影响。     

The ethno-class trajectory of new neighborhoods in Israel

The subject of this article falls within the debate on the development of new neighborhoods beyond the hub of the metropolis and how this relates to planning from below. It regards new neighborhoods as being increasingly shaped through deliberate action in the form of public policy at the state and local levels. However, it emphasizes the central role of the government establishment, national institutions and ideologies in walling out and exclusionary practices. Research into four representative new neighborhoods in Israel, which were planned under the new spatial regime of the 1990s, reveals patterns of discrimination and ethno-class stratification that enable the preservation of nationalism and ethnic logic as the main, yet concealed, axis organizing social and spatial life.     

High density neighborhoods: Who enjoys them?

To date, research into the subjective aspects of high density has focused mainly on the negative consequences of overcrowding. This study, in contrast, outlines some of the positive aspects of high density in neighborhoods, exploring the physical–spatial environment of two neighborhoods in the city of Haifa, Israel. It was found that while the relatively high residential density was similar in both neighborhoods (40 housing units per acre), this was more positively evaluated in one neighborhood as compared to the other. This can be attributed to some specific environmental and planning features. In particular, where physical planning enabled the potential advantages of high density to be realized, this was positively perceived and evaluated by local residents. Such advantages mainly comprised accessibility to a variety of services, more frequent public transportation, and access to open spaces within walking distance. Particularly advantageous were the increased opportunities for social gathering. At the same time, however, high density did not foster social relationships on the neighborhood level. The study further identified the gender and age groups that benefited most from the high density. Thus, women evaluated high density more positively than men. Young families with children and senior citizens (over 65) were also more likely to benefit, and to evaluate the high density environment more positively than other social groups.     

基于矢量网格的城市土地利用邻里模式研究

城市土地利用的空间分布特征一直是城市地理和城市规划领域关注的重点问题,对城市土地利用空间模式的研究有助于理解城市系统的运行状态。在分析现有城市空间结构和城市土地利用模式的基础上,从两个方面对现有基于富集因子的分析方法提出改进,一是采用矢量网格以减少分析的误差,二是采用斜网格和曼哈顿距离来对空间临近关系进行界定。采用这一方法对深圳市2015年6类城市土地利用数据进行分析,得到邻里尺度上各类用地之间富集度随距离变化的3种模式。模式I中,同类用地间的富集度在短距离内较大,且其值随着距离的增加而减小并趋于0,表明同类用地间在较短距离内相互吸引,而吸引力随着距离增加而减弱。在不同类型用地间的模式II和模式III中,富集度在较短距离内为负值,但是在模式II中,富集度随着距离的增加而逐渐增加并趋于0,表明不同用地间短距离内相互排斥,且排斥作用随着距离增加而减弱;而在模式III中,富集度则随着距离增加而快速上升到正值,然后逐渐下降并趋于0,表明不同类型用地在较短距离内相互排斥,但随着距离增加很快变为相互吸引,最后吸引力随着距离增加慢慢减弱。结果表明,相对于基于栅格网的分析方法,基于矢量斜网格的分析方法能够显著降低分析误差。     

Neighborhood size and spatial scale in raster-based slope calculations

Raster-based slope estimation is routine in GIS. Like many other terrain attributes, the slope at a location is determined from elevations of surrounding cells. This spatial extent – ‘neighborhood size’ – is often treated as the ‘spatial scale’ of the calculation. In fact, neighborhood size and spatial scale are two connected yet different concepts, but few studies have investigated the relationship between them. The distinction is important because neighborhood size is under user control whereas spatial scale is merely implicit in the computational method. This article attempts to clarify and provide a more precise meaning of the two terms by considering slope operators from the standpoint of the frequency (or wavenumber) domain. This article derives analytical expressions for the amplitude response functions of four popular slope estimators. These are used to characterize the individual methods and also to show that the neighborhood size and spatial scale of a slope calculation are not numerically the same. In fact, because there is no single spatial scale that can be unambiguously associated with a given neighborhood size, neighborhood size cannot be an adequate indicator of spatial scale. Furthermore, this article shows that different indices of ‘scale’ yield different impressions about the action of a slope estimator and its response to changing neighborhood size. Therefore, it is necessary to examine the amplitude response function when investigating the spatial scale. The article also provides guidance for GIS practitioners when selecting a slope estimation method.     

COMMENTS ON “SPATIAL VARIATION OF HILLSLOPE PROFILES IN THE CUMBERLAND PLATEAU,KENTUCKY” BY EDMUND B. WOOOS

Book Reviewed in this article:

Main Street: Northeastern Oregon: The Founding and Development of Small Towns. Barbara Ruth Bailey.

Food Politics: The Regional Conflict. David N. Balaam and Michael J. Carey, eds.

The International Economy and Industrial Development: Trade and Investment in the Third World. R. Ballance, J. Ansari and H. Singer.

Neighborhoods in Urban America. Ronald H. Bayor, ed.

The English Heartland. By Robert Beckinsale and Monica Beckinsale.

Regional Dimensions of Industrial Policy. Michael E. Bell and Paul S. Lande, eds.

Tension Areas of the World. D. Gordon Bennett, ed.

Latin America: an Introductory Survey. B. W. Blouet and O. M. Blouet, eds.

Integration and Division: Geographical Perspectives on the Northern Ireland Problem. Frederick W. Boal and J. Neville H. Douglas, eds.

Energy and Land Use. Robert W. Burchell and David Listokin, eds.

Slopes and Weathering. Michael Clarke and John Small.

Alaska's Rural Development. Peter G. Cornwall and Gerald McBeath, eds.

The Politics of Park Design: A History of Urban Parks in America. Galen Cranz.

World Congress on Land Policy, 1980, Proceedings. Matthew Cullen and Sharon Woolery, eds.

Oregon Divided: A Regional Geography. Samuel N. Dicken and Emily F. Dicken.

Urban Food Marketing and Third World Rural Development. T. Scarlett Epstein.

South Africa: Spatial Frameworks for Development. T. J. D. Fair.

Institutions and Geographical Patterns. Robin Flowerdew, ed.

Industrialization of U.S. Agriculture, An Interpretive Atlas. Howard F. Gregor.

Planning Theory: Prospects for the 1980s. Patsy Healy, Glen McDougall and Michael J. Thomas, eds.

Neighborhood Mobilization: Redevelopment and Response. Jeffrey R. Henig.

The American Urban System: A Geographical Perspective. R. J. Johnston.

Climate, History and the Modern World. Hubert H. Lamb.

Climate and History: Studies in Past Climates and Their Impact on Man. T. M. L. Wigley, M. J. Ingram and G. Farmer.

China: Railways and Agricultural Development, 1875–1935. Ernest P. Liang.

A Desirable Energy Future—A National Perspective. Robert S. Livingston, T. D. Anderson, T. M. Besmann, M. Olszewski, A. M. Perry, and C. D. West.

Topothesia: Essays Presented to T. S. Ó Máille. B. S. Mac Aodha, ed.

Transportation for the Poor: Research in Rural Mobility. Hal S. Maggied.

Land Uses in American Cities. Harold M. Mayer and Charles R. Haves.

Industrial Organisation and Location. Philip McDermott and Michael Taylor.

Human Adaptability: an Introduction to Ecological Anthropology. Emilio F. Moran.

Regional Analysis and the New International Division of Labor. Frank Moulaert and Patricia W. Salinas, eds.

The Nuclear War Atlas. Victoriaville, Quebec, Canada:

Urbanization and Environmental Quality. Isao Orishimo.

The Garden of Eden: The Botanic Garden and the Re-Creation of Paradise. John Prest.

Earthfire, The Eruption of Mount St. Helens. Charles Rosenfeld and Robert Cooke.

Contest for the South China Sea. Marwyn S. Samuels.

The Future of the Wetlands: Assessing Visual-Cultural Values. Richard C. Smardon, ed.

Tucson: the Life and Times of An American City. C. L. Sonnichsen.

The Geography of Multinationals. Michael Taylor and Nigel Thrift, eds.

Impact of Marine Pollution on Society. Virginia Tippie and Dana Kester.

Reviving the Industrial City: the Politics of Urban Renewal in Lyon and Birmingham. Jerry A. Webman.

Andean Reflections: Letters from Carl O. Sauer While on a South American Trip under a Grant from the Rockefeller Foundation, 1942. Robert C. West, ed.

Cartographic Drawing with Computers. P. Yoeli.     

Sense of Place in Hamilton,Ontario: Empirical Results of a Neighborhood-Based Survey

Although the concept of sense of place has a long history in the social sciences, relatively few studies have attempted a quantitative analysis of sense of place at the neighborhood level. This study reports on the empirical findings of a sense of place survey developed and tested in two contrasting neighborhoods in Hamilton, Ontario, Canada: Southwest Mountain, an upper-middle-class suburban neighborhood and Northeast Industrial, a lower-income, working-class neighborhood located in the heart of the city's industrial district. The principal objective is to assess the relationship between sense of place and the socio-demographic characteristics of residents living in neighborhoods of very different socioeconomic status. This study also introduces a method for calculating a neighborhood sense of place score derived from a fully tested, validated survey instrument. It was found that sense of place was strongest in Southwest Mountain, and among seniors, long-term residents, unmarried people, and immigrants. In addition, residents with a lower level of education and those in the unpaid labor force had a stronger sense of place.     

Characterization of bacterial symbioses in Myrtea sp. (Bivalvia: Lucinidae) and Thyasira sp. (Bivalvia: Thyasiridae) from a cold seep in the Eastern Mediterranean

Cold seeps have recently been discovered in the Nile deep‐sea fan (Eastern Mediterranean), and data regarding associated fauna are still scarce. In this study, two bivalve species associated with carbonate crusts and reduced sediment are identified based on sequence analysis of their 18S and 28S rRNA‐encoding genes, and associated bacterial symbioses are investigated using 16S rRNA gene sequencing and microscopy‐based approaches. The specimens are closely related to Myrtea spinifera and Thyasira flexuosa, two species previously documented at various depths from other regions but not yet reported from the Eastern Mediterranean. Both species harbour abundant gammaproteobacterial endosymbionts in specialized gill epithelial cells. The Myrtea‐associated bacterium is closely related to lucinid symbionts from both deep‐sea and coastal species, whereas the Thyasira‐associated bacterium is closely related to the symbiont of a T. flexuosa from coastal waters off the U.K. An epsilonproteobacterial sequence has also been identified in Thyasira which could correspond to a helicoid‐shaped morphotype observed by electron microscopy, but this was not confirmed using fluorescent in situ hybridization. Virus‐like particles were observed within some symbionts in Thyasira, mostly in bacteriocytes localized close to the ciliated zone of the gill filament. Overall, results indicate that very close relatives of shallow species M. spinifera and T. flexuosa occur at cold seeps in the Eastern Mediterranean and harbour chemoautotrophic symbioses similar to those found in their coastal relatives.