A trajectory clustering approach based on decision graph and data field for detecting hotspots   总被引：2，自引：0，他引：2  

Pengxiang Zhao  Xinyue Ye  Yulong Wang  Yixiang Chen 《International journal of geographical information science》2017,31(6):1101-1127

Spatial clustering can be used to discover hotspots in trajectory data. A trajectory clustering approach based on decision graph and data field is proposed as an effective method to select parameters for clustering, to determine the number of clusters, and to identify cluster centers. Synthetic data and real-world taxi trajectory data are utilized to demonstrate the effectiveness of the proposed approach. Results show that the proposed method can automatically determine the parameters for clustering as well as perform efficiently in trajectory clustering. Hotspots are identified and visualized during different times of a single day and at the same times on different days. The dynamic patterns of hotspots can be used to identify crowded areas and events, which are crucial for urban transportation planning and management.  相似文献   

城乡交错带的三维动态识别及空间演变机制——以厦门市为例     

梁晨  曾坚 《地理研究》2021,40(5):1404-1420

城乡交错带是人地系统矛盾最集中的区域之一,对其进行科学识别与动态监测对中国新时期城乡统筹和空间治理有重大意义。提出了一种综合城乡交错带三维特征指数、动态线性加权与空间自相关分析的空间识别方法,基于LULC数据提取了厦门市1990—2018年城乡交错带的空间范围,进一步通过GIS揭示其格局规模、土地利用、空间功能的演变特征和机制。结果表明：① 城乡交错带三维动态识别方法在长时序空间识别中效果良好。② 近30 a厦门城乡交错带规模持续扩大并向陆域腹地推移,包括“组团生成-连片外延-跳跃扩张-内部分异”四种模式,存在外圈扩张与内圈消减的双重过程。③ 土地利用动态和面积变化速率分别在2010年达到顶峰26.85%和22.70 km²/a后降低并趋稳,研究期内建设用地对耕地和其他生态空间不断侵蚀。④ 空间功能混合度持续增强,复合功能空间占比由63.80%提升至75.72%,其中生产、生态功能在城市化前期和中期存在较强权衡关系,生活功能最薄弱。⑤ 城乡交错带空间演进包括三个阶段,受经济、社会、政策、环境四方面因素共同驱动。研究对补充城市地域结构理论体系有一定价值,为城乡交错地区国土空间规划实践提供支撑。  相似文献   

基于文献计量学分析岩溶水文地质学研究热点     

郭永丽  章程  吴庆  全洗强 《中国岩溶》2020,39(6):817-828

利用文献计量学方法分析2011-2018年国内外岩溶水文地质学领域研究的动态特征。通过Web of Science（WoS）核心合集数据库,以“Karst hydrogeology”、“Karst groundwater”、“Karst aquifer”、“Karst underground river”、“Karst subterranean stream”、“Karst underground stream”、“Karst spring”“Karst geothermal water”、“Karst thermal groundwater”或“Karst water landscape”为主题词,检索得到1 460篇论文,通过中国知网（CNKI）收录的EI、核心期刊和CSSCI数据库,以“岩溶水文地质”、“岩溶地下水”、“岩溶含水层”、“喀斯特水文地质”、“喀斯特地下水”、“喀斯特含水层”、“地下河”、“岩溶泉水”、“岩溶地热水”、“喀斯特泉水”、“喀斯特地热水”、“岩溶水景观”或“喀斯特水景观”为主题词,检索得到918篇论文。基于WoS和CNKI自带功能及CiteSpace软件分析国家、机构、发文量及期刊等情况,结果表明:中国地质科学院岩溶地质研究所充分发挥了其在国内的机构职能和专业优势,中国有待进一步加强其在国际上的地域优势及其活跃度;由基于CiteSpace平台的关键词共现图谱发现国际岩溶水文地质学领域研究的热点问题包括“岩溶水动力学”、“岩溶地下水数值模拟”、“岩溶水文地球化学”和“岩溶水污染”,而国内岩溶水文地质学领域研究的热点问题范围更广,包括“岩溶含水系统”、“岩溶水资源”、“岩溶水环境”和“岩溶水文工程”。   相似文献   

国内外海岛保护与开发的发展态势     

江春嬉  张灿影  霍达  杨红生 《海洋科学》2022,46(2):113-126

本研究以科学引文索引(Science Citation Index Expanded,SCIE)和中国知网数据库为基础,利用文献计量方法,对国内外海岛研究相关文献的年代、关键词、研究内容、发文期刊、发文国家及研究机构等进行了全面的统计分析.结果表明:国内外海岛研究的热点主要为海岛旅游业、海岛可持续开发管理、海岛生物群落...  相似文献   

Hotbeds of crime and the search for spatial accuracy   总被引：1，自引：1，他引：0  

J. H. Ratcliffe  M. J. McCullagh 《Journal of Geographical Systems》1999,1(4):385-398

One of the most important aspects of spatial crime analysis is the identification of hotspots: areas of the highest crime concentration. This paper advances a methodology for hotspot detection based on a global moving window approach combined with the use of local statistics to define the hotspot limit. This technique generates hotspots that both follow the urban morphology of the crime distribution and ensures their spatial segregation. The hypothesis that police officers can construct an accurate perception of crime distribution from exposure to daily policing practices is used to demonstrate an application in the use of hotspot analysis. Significant regions generated from recorded crime data are compared with perceived local hotspots catalogued from surveys with police officers. Results from this study show two discrete types of hotspot, here termed hotpoints and hotbeds. The morphology of these crime hotpoints and hotbeds is discussed and possible causes documented. Received: 9 October 1998/Accepted: 22 September 1999  相似文献   

Hawaiian volcanic propagation and Hawaiian swell asymmetry: evidence of northwestward flow of the deep upper mantle     

R. T. Cox 《Tectonophysics》1999,310(1-4):69-79

Bathymetry and the geoid anomaly of the northern flank of the Hawaiian swell is broader and higher than the southern flank, and it is characterized by higher heat flow than the axis or southern flank. It is here proposed that the northern flank of the Hawaiian swell has been augmented by heat conducted from the hotspot conduit into the upper mantle then transported northward of the volcanic axis by flow in the upper mantle (325°) that is more northerly than Pacific plate motion (292°). By assuming that the deep upper mantle is decoupled from the Pacific plate and is flowing at 325° to the northwest, changes in direction and rate of volcanic propagation and in geochemistry along individual volcanic segments of the Hawaiian volcanic chain can be interpreted in terms of tank experiment results showing that a volcanic hotspot conduit breaks into diapirs when tilted by mantle flow. Hawaiian volcanoes are aligned in en-echelon segments, and the Hawaiian Islands are the two most recent segments. For an individual segment, older northwestern volcanoes are aligned nearly parallel to the 292° plate motion direction, and they propagated to the southeast at approximately the same rate as the 92 km/m.y. speed of northwestward plate motion. In contrast, the alignment of the younger southeastern volcanoes is close to 325°, and they show a conspicuous acceleration in propagation of volcanism marked by out-of-sequence eruptions. Within the model proposed here, diapirs rise from instability nodes that develop along the tilted conduit of a mantle hotspot plume as it is sheared in the direction of deep upper-mantle flow and each diapir gives rise to a single volcanic center. As tilting progresses, diapirs form at lower levels along the conduit in more upstream positions of the mantle flow zone, rise sequentially into the decoupled lithosphere, erupt sequentially, and are translated in the direction of plate motion (older, northwestern Hawaiian Islands). Eventually, flow in the highly tilted conduit is impeded to the degree that the remaining upstream conduit breaks into a number of diapirs that rise together into the lithosphere. These late diapirs, translated as a group aligned in the direction of horizontal mantle flow, erupt over a relatively short time span and show out-of-sequence volcanism (younger, southeastern Hawaiian Islands). At this stage, a new cycle of rising and tilting will initiate the next en-echelon segment.  相似文献   

空间尺度对Getis-Ord Gi*获取的CPUE热点模式的影响：以西北太平洋柔鱼为例     

冯永玖  陈新军  高峰  刘杨 《海洋学报(英文版)》2018,37(5):67-76

空间尺度（渔业网格）不仅影响CPUE全局分布模式，而且影响其局部分布模式及其与海洋环境的关系。在空间多尺度下，本文研究了西北太平洋柔鱼（Ommastrephes bartramii）CPUE热点和冷点分布的尺度关系和尺度效应。将原始渔业数据重采样为从5''×5''到90''×90''的18个空间尺度，以5''的尺度间隔来识别局部聚类簇。论文系统分析了Getis-Ord Gi*热点和冷点的位置、边界、经典统计量随空间尺度的变化。具体地，分析了空间热点和冷点的最小值（Min）、均值（Mean），最大值（Max）、标准差（SD）、变异系数（CV）、偏度、峰度、第一四分位数（Q1）、中位数、第三四分位数（Q3）、面积和质心等统计量的空间尺度影响。在空间尺度影响分析中，主要考虑线性、对数、指数、幂律和多项式等尺度研究中的常见关系。对于热点和冷点，最大值、标准偏差和峰度具有显著的空间尺度关系，其余统计量一部分在热冷点间存在尺度影响的差异，而另一部分没有明确的尺度关系。研究结果表明，由于不同尺度的热点和冷点的边界和位置与原始尺度的边界和位置明显不同，不建议采用大于30''的网格来分析柔鱼资源的局部空间模式。  相似文献   

Spatial Distribution and Dynamic Changes in Research Hotspots for Desertification in China based on Big Data from CNKI     

LIANG Yuting  HU Yunfeng  HAN Yueqi 《资源与生态学报(英文版)》2019,10(6):692-703

Desertification research plays a key role in the survival and development of all mankind. The Normalized Comprehensive Hotspots Index (NCH) is a comprehensive index that reveals the spatial distribution of research hotspots in a given research field based on the number of relevant scientific papers. This study uses Web Crawler technology to retrieve the full text of all Chinese journal articles spanning the 1980s-2018 in the Chinese Academic Journal full-text database (CAJ) from CNKI. Based on the 253,055 articles on desertification that were retrieved, we have constructed a research hotspot extraction model for desertification in China by means of the NCH Index. This model can reveal the spatial distribution and dynamic changes of research hotspots for desertification in China. This analysis shows the following: 1) The spatial distribution of research hotspots on desertification in China can be effectively described by the NCH Index, although its application in other fields still needs to be verified and optimized. 2) According to the NCH Index, the research hotspots for desertification are mainly distributed in the Agro-Pastoral Ecotone and grassland in Inner Mongolia, the desertification areas of Qaidam Basin in the Western Alpine Zone and the Oasis-Desert Ecotone in Xinjiang (including the extension of the central Tarim Basin to the foothills of the Kunlun Mountains, the sporadic areas around the Tianshan Mountains and the former hilly belt of the southern foothills of the Altai Mountains). Among these three, the Agro-Pastoral Ecotone in the middle and eastern part of Inner Mongolia includes the most prominent hotspots in the study of desertification. 3) Since the 1980s, the research hotspots for desertification in China have shown a general downward trend, with a significant decline in 219 counties (10.37% of the study area). This trend is dominated by the projects carried out since 2002. The governance of desertification in the eastern part of the Inner Mongolia-Greater Khingan Range still needs to be strengthened. The distribution of desertification climate types reflects the distribution of desertification in a given region to some extent. The Normalized Comprehensive Hotspots Index provides a new approach for researchers in different fields to analyze research progress.  相似文献   

长春市财产犯罪的空间分析   总被引：11，自引：5，他引：6  

刘大千  修春亮  于嘉 《地理科学》2012,(4):477-484

基于长春市公安局提供的警区层面的犯罪数据,分析了长春市2008年财产犯罪率的空间分布特征。研究发现长春市财产犯罪率呈现出城市中心高而外围低的圈层式空间模式。通过对犯罪高发区域的用地性质和功能的分析发现,长春市主要商业区和主要客运交通枢纽所在警区均具有较高的财产犯罪率。利用空间分析的方法,判定出长春市财产犯罪的热点地区,从统计学意义上验证了犯罪活动的空间集聚性,进而推测这些区域可能存在犯罪扩散和溢出效应。借鉴国外相关理论及实证研究,结合长春市实际情况,通过回归建模分析,探讨了长春市财产犯罪率同人口、社会经济、土地利用等各因子可能存在的相互关系,发现长春市财产犯罪率受到人口密度、就业活跃度、商业区、服务业活跃度、客运枢纽和年轻人口比例的显著影响,在一定程度上支持了日常活动理论的基本观点,但需结合长春市实际情况做具体分析与解释。  相似文献   

近20年来中国生态补偿研究热点分析——基于文献计量研究     

刘某承  白云霄  苏伯儒 《资源与生态学报(英文版)》2022,13(1):80-92

近年来,生态补偿作为生态文明的重要组成部分,在学术界获得了广泛的关注。本研究运用知识图谱工具CiteSpace对CNKI数据库中学术期刊收录的生态补偿研究的相关文献进行梳理分析,以期为该领域研究提供更客观、科学的参考。结果表明:国内有关生态补偿的研究在2000年左右开始出现,并于2009年迎来第一个研究热潮;国内学者多从生态补偿的内涵、补偿主客体、补偿标准、补偿方式、补偿监管与补偿效果的评估等方面对生态补偿进行研究和探讨,特别是有关生态补偿标准的文章相对较多。同时,生态补偿研究还常常与生态系统服务价值和生态产品价值实现相联系。未来,研究者应着重关注建立和完善生态补偿标准核算体系、探索市场化的生态补偿机制、重视生态补偿资金分配机制,以及加强生态补偿效果评估的相关研究,以推动生态补偿理论朝着纵深化方向发展,为我国处理好保护与发展之间的关系提供新的研究视角。  相似文献