Composite spectra paper 2: HD 88021/2

HD 88021/2 (ADS 7662) is a very close visual binary. The accepted visual orbit, which is of very high eccentricity and graded “reliable”, led to the expectation of a periastron passage in 1981, when there should have been a large difference in radial velocity between the components. No such event took place, and there is little indication that it is likely to occur in the near future. A new interpretation of the visual orbital data leads to an orbit of a different character from those hitherto proposed. A decision between the competing orbits should be possible within a very few years. Meanwhile, the method of spectral subtraction developed in Paper 1 has enabled us to separate the spectra of the two components and to show that their spectral types are K0 III and A2m.     

Studies of multiple stellar systems – IV. The triple-lined spectroscopic system Gliese 644

We present a radial velocity study of the triple-lined system Gliese 644 and derive spectroscopic elements for the inner and outer orbits with periods of 2.965 5 and 627 d. We also utilize old visual data, as well as modern speckle and adaptive optics observations, to derive a new astrometric solution for the outer orbit. These two orbits together allow us to derive masses for each of the three components in the system: M _A=0.410±0.028 (6.9 per cent), M _Ba=0.336±0.016 (4.7 per cent), and M _Bb=0.304±0.014 (4.7 per cent) M_⊙. We suggest that the relative inclination of the two orbits is very small. Our individual masses and spectroscopic light ratios for the three M stars in the Gliese 644 system provide three points for the mass–luminosity relation near the bottom of the main sequence, where the relation is poorly determined. These three points agree well with theoretical models for solar metallicity and an age of 5 Gyr. Our radial velocities for Gliese 643 and vB 8, two common proper motion companions of Gliese 644, support the interpretation that all five M stars are moving together in a physically bound group. We discuss possible scenarios for the formation and evolution of this configuration, such as the formation of all five stars in a sequence of fragmentation events leading directly to the hierarchical configuration now observed, versus formation in a small N cluster with subsequent dynamical evolution into the present hierarchical configuration.     

BOOK REVIEWS

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 Mc Beath , 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 Mc Dougall 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 Mc Dermott 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 .     

土地复垦美学视觉评价:以黄土高原矿区为例

目前国内外很少有从美学角度进行土地复垦的研究,土地复垦美学概念暂未提出,土地复垦美学视觉评价体系还未成熟。为深入研究土地复垦美学概念内涵,讨论土地复垦美学表现形式,本文参考平朔矿区土地复垦与生态修复的经验,采用文献归纳法和移植研究法,以“山水林田湖草生命共同体理念”为依托,构建了由要素评价和系统评价组成的嵌套式评价体系。通过解构美国林务局视觉管理系统(visual management system,VMS)评价、美国土地管理局视觉资源管理系统(visual resource management,VRM)、联邦公路局视觉影响评估系统(visual impact assessment,VIA)、复田景观评价、园林景观美学评价等成熟的视觉评价体系,结合矿区生态系统修复“五元共轭”理论,构建了一套适用于黄土高原矿区的土地复垦美学视觉评价体系,所有指标共计21项,即地貌重塑与土壤重构相关指标8项、植被重建与生物多样性相关指标7项、景观重现相关指标6项。各项指标完成了定性、半定量化释义,修正了“岩貌、地形地貌、湖泊、毗邻景观”4项指标的评价标准。土地复垦美学评价不可忽略主观因素影响,应注重景观美学表现形式的多样性与差异性,使土地复垦美学视觉表现得更具选择性。     

Prevalence of the terrain reversal effect in satellite imagery

The terrain reversal effect is a perceptual phenomenon which causes an illusion in various 3D geographic visualizations where landforms appear inverted, e.g. we perceive valleys as ridges and vice versa. Given that such displays are important for spatio-visual analysis, this illusion can lead to critical mistakes in interpreting the terrain. However, it is currently undocumented how commonly this effect is experienced. In this paper, we study the prevalence of the terrain reversal effect in satellite imagery through a two-stage online user experiment. The experiment was conducted with the participation of a diverse and relatively large population (n = 535). Participants were asked to identify landforms (valley or ridge?) or judge a 3D spatial relationship (is A higher than B?). When the images were rotated by 180°, the results were reversed. In a control task with ‘illusion-free’ original images, people were successful in identifying landforms, yet a very strong illusion occurred when these images were rotated 180°. Our findings demonstrate that the illusion is acutely present; thus, we need a better understanding of the problem and its solutions. Additionally, the results caution us that in an interactive environment where people can rotate the display, we might be introducing a severe perceptual problem.     

可视化建模技术在GIS中的研究与应用

可视化建模是利用围绕现实想法组织模型的一种思考问题的方法。该技术以其简化需求、易于理解问题、沟通问题等特点被广泛应用于软件开发的各个环节中。本文分析了空间信息处理的特点,结合可视化建模和工作流的技术,提出了空间处理建模的概念,并探讨了空间处理建模的建模流程及应用方式。     

Perceptual complexity of soil-landscape maps: a user evaluation of color organization in legend designs using eye tracking

ABSTRACT

We compared the ability of two legend designs on a soil-landscape map to efficiently and effectively support map reading tasks with the goal of better understanding how the design choices affect user performance. Developing such knowledge is essential to design effective interfaces for digital earth systems. One of the two legends contained an alphabetical ordering of categories, while the other used a perceptual grouping based on the Munsell color space. We tested the two legends for 4 tasks with 20 experts (in geography-related domains). We analyzed traditional usability metrics and participants’ eye movements to identify the possible reasons behind their success and failure in the experimental tasks. Surprisingly, an overwhelming majority of the participants failed to arrive at the correct responses for two of the four tasks, irrespective of the legend design. Furthermore, participants’ prior knowledge of soils and map interpretation abilities led to interesting performance differences between the two legend types. We discuss how participant background might have played a role in performance and why some tasks were particularly hard to solve despite participants’ relatively high levels of experience in map reading. Based on our observations, we caution soil cartographers to be aware of the perceptual complexity of soil-landscape maps.     

An improved Bag-of-Words framework for remote sensing image retrieval in large-scale image databases

Due to advances in satellite and sensor technology, the number and size of Remote Sensing (RS) images continue to grow at a rapid pace. The continuous stream of sensor data from satellites poses major challenges for the retrieval of relevant information from those satellite datastreams. The Bag-of-Words (BoW) framework is a leading image search approach and has been successfully applied in a broad range of computer vision problems and hence has received much attention from the RS community. However, the recognition performance of a typical BoW framework becomes very poor when the framework is applied to application scenarios where the appearance and texture of images are very similar. In this paper, we propose a simple method to improve recognition performance of a typical BoW framework by representing images with local features extracted from base images. In addition, we propose a similarity measure for RS images by counting the number of same words assigned to images. We compare the performance of these methods with a typical BoW framework. Our experiments show that the proposed method has better recognition performance than that of the BoW and requires less storage space for saving local invariant features.     

川东北长兴组—飞仙关组古原油成藏的孔隙度门限

近年来,在四川盆地二叠系、三叠系海相碳酸盐岩层系中发现了如普光、龙岗、元坝等多个大中型、高孔高渗气田,且天然气主要为古油藏原油裂解气.在油源充足的条件下,孔隙度成为了控制古原油成藏的关键因素,讨论古原油充注的孔隙度门限,尤其对于致密碳酸盐岩储层是否发生古原油的聚集具有指导意义.川东北地区长兴组-飞仙关组礁滩相储层发现了大量的固体沥青,岩石薄片镜下观察到这些固体沥青主要分布于亮晶鲕粒灰岩的粒间孔隙中、结晶白云岩的晶间孔中以及残余鲕粒白云岩的铸模孔中,极少发现沥青充填之后的胶结物.本研究定量统计了沥青含量与现今面孔隙度来恢复视古孔隙度,分别讨论现今面孔隙度、视古孔隙度与沥青含量的关系,确定了视古孔隙度门限,最后经过压实作用校正得到了古原油成藏的孔隙度门限.研究结果揭示,沥青含量与现今面孔隙度无线性关系.而与视古孔隙度有着较明显的正相关关系,当视古孔隙度大于一定值时,沥青含量显著增加;川东北长兴组-飞仙关组碳酸盐岩储层古原油成藏的孔隙度门限值为6.4％～7.4％(平均6.8％).