基于Android平台的街景采集系统的研究

随着国民经济的发展、人们生活水平的提高,城市各街道的商铺、建筑物等更替速度越来越快,更新缓慢的街景地图服务已经无法满足日常生活的需求。专业的街景采集存在成本高、见效周期长、盈利性差、更新速度慢等诸多弊端。随着智能手机的广泛使用和手机像素的不断提高,街景采集工作出现了新的方式。本文以基于Android平台的街景数据采集系统为研究对象,对目前国内街景采集的现状进行了详细研究,设计数据库构架并阐述了在Android手机上建立库的流程。并以Eclipse为开发平台,利用Android SDK、高德地图SDK、ADT等插件,采用嵌入式开发方法,在Android手机上实现街景数据的采集、本地街景数据的存储管理和GIS的相关功能。     

基于倾斜摄影的三维城市建模研究

基于街景工厂与徕卡RCD-30倾斜摄影测量系统,研究了快速处理高分辨率、大数据量倾斜影像的技术流程,并以实际项目为例进行了数据处理,对项目的模型接边、模型效果、模型精度进行了分析和总结,对倾斜摄影技术在我国大规模的应用具有一定的指导意义。     

An effective spherical panoramic LoD model for a mobile street view service

Street view (panoramic view) services have begun to shift from PC platforms to mobile smart devices. Considering the capabilities of smart terminal devices, a 360° spherical level of detail (LoD) model for mobile street view services that renders panoramic images on the inner surface of a sphere via LoD is proposed in this article. Panoramic images are segmented into tiles and organized in a pyramid tile structure for LoD rendering to improve the rendering efficiency of the proposed model. A projection model between panoramic images and the spherical surface is presented to map the panoramic tiles on the spherical graticule. A street view‐rendering algorithm of panoramic images is proposed with the rendering function of OpenGL for Embedded Systems (OpenGL ES). A street view service app running on Android, based on the proposed approach, is implemented to assess two aspects of the panoramic view model, namely visualization effect and efficiency. Experiment results reveal that the 360° spherical LoD model of the panoramic image can display 3D street view scenes better than the cubic panoramic view model. The proposed model also has an excellent 3D visualization effect and high‐efficiency rendering ability for mobile street view services. Therefore, it is applicable in large‐scale mobile street view services both online and offline and in augmented reality navigation.     

The “von Karman vortex street” to the west of Big Island

Satellite-tracked drifting buoy data and altimetry data are used to study the active vortex field to the west of Big Island. A pair of vortexes were observed at the trajectory of buoy in 1995. The westward propagation of the vortex pair is studied in detail by reproducing the loops of each vortex. The orbital period and radius of the pair of vortex are determined to be 10-11 d and 58-68 km. Two arrays of contra-rotating vortices are displayed in the average sea surface height anomaly (SSHA) field to the west of Big Island. Based on the calculation of the fluid dynamical parameter, the “von Karman vortex street” is proved to be generated to the west of Big Island as the North Equatorial Current impinges upon Big Island from the east. Finally, the analysis of the buoy trajectories in a decade contributes to the conclusion of the pattern of VKVS in a statistical view.     

城市街道级GIS设计与研究

阐述了城市街道级GIS的概念及意义,并对城市街道级GIS的设计与实现方法进行研究,特别是城市大比例尺数据的分类、组织。以泰安市街道级GIS应用系统为例,详细阐述了街道级GIS设计的数据组织与管理、总体功能框架、系统功能模块等,解决了公交换乘、多媒体信息组织与管理等问题。     

扫描地形图中居民地街区提取和矢量化方法

提出了特征点提取和总体最小二乘拟合相结合的新方法,对扫描地图上的居民地街区进行提取和矢量化。本文首先对居民地街区进行轮廓跟踪得到初始的矢量数据,通过特征点提取进行数据压缩,再利用总体最小二乘方法对每条边线进行拟合,得到最终的矢量数据。此外,还提出了三个精度指标,对实验图中矢量数据的精度进行定量分析。结果表明,该方法能够提高居民地街区矢量化的准确性,消除冗余数据。     

街景影像中的斑马线检测与定位

针对街景影像中斑马线的自动检测与定位识别率和定位精度不高的问题,文章引入俯视投影与霍夫直线检测来改进基于双极系数的斑马线识别算法,并设计球面全景单像测量方法对斑马线进行粗略定位:对全景图像上路面区域进行俯视投影,使图像各处比例尺保持一致;对路面俯视图分块计算以生成双极系数图,并用形态学中闭运算与开运算进行处理;对候选区域进行霍夫直线检测,利用直线长度与方向的统计信息来排除干扰;最后使用单像量测方法对斑马线进行自动地理定位。实验结果证明,该方法对街景中的斑马线具有较高的识别率与定位精度。     

VORTEX MOTIONS IN THE ATMOSPHERIC CONVECTIVE BOUNDARY LAYERM*

Large vortices with scales ranging from hundreds meters to tens of kilometers are generally found in the atmospheric convective boundary layer(CBL).These vortices play important roles in the vertical transport of momentum,heat,water vapor and other tracers in the boundary layer.On the basis of the view of interaction between the convection in CBL and the gravity waves in the upper stable layer the authors developed a convection-wave theory on the formation of large vortices.According to the theory the wavenumber spectrum of the large vortices mainly depends on the atmospheric conditions in both of the upper and lower layers,such as wind speed,wind direction shear,stratification as well as temperature jump.In the present paper satellite image and weather data in a case of cold air outbreak over warm ocean are analyzed to study every stage of the convective processes,such as cloud street,convective cell as well as their transformation.According to the theory the wavenumber compositions for cloud street and convective cell are calculated,respectively,on the basis of the atmospheric conditions at every stage.The distributions of vertical motions,convergent band and disturbed interface are obtained and compared with the cloud patterns in the convective processes.Thus the study seems to offer a likely explanation for the origin of large vortices in CBL.     

街道的城市地址编码模型与实验

地址编码是指将地址映射成地理坐标的过程,它提供了一种把描述性地理位置信息转换成GIS地理坐标的方式。本文分析了当前标准规范中的地址编码规则,认为街道与小区等院落实体作为同级别的区域限定物弱化了街道的空间特征,并且在现有地址编码规则基础上提出了将街道前置作为区域限定物的地址编码改进方案;进一步,为了体现街道作为各类地理实体的空间参考基础,本文按照街道的前进方向,定义了在街道线性空间中的地理实体链表组织模型,实现了将相互独立的地址编码实体在街道中的串联组织,从而为今后地址查询中的参考定位提供了模型支持;最后,给出了街道两侧不同类型地理实体纳入街道地址编码实体链表的实例说明。     

宁波老外滩酒吧街的不得其所与地方建构

酒吧作为城市休闲空间的代表,近年来迅速地在中国城市中扩散。欧美世界的酒吧与地方秩序、社会问题联系紧密,第三世界的酒吧经常被西方学者作为西方的文化飞地,地方权力集中的代表。运用克里斯威尔的“不得其所”为概念框架,以中国沿海城市宁波的一条酒吧街老外滩为案例地,通过问卷调查与访谈观察中外消费者的不同消费行为及空间选择,探讨中国酒吧街的权力结构,试图找出一条不同于西方语境的地方权力建构路径。所得结论如下：① 宁波老外滩酒吧街的“不得其所”现象表现为：中外消费者在选择酒吧上是空间分离的,而且在中国消费者存在的酒吧并不欢迎外国消费者,这一现象建构了酒吧街的地方性;② 参与老外滩地方性建构的主要力量是中外消费者,其中中国消费者在建构地方性中占据主导地位,他们不仅不再将酒吧街作为外国人消费的场所,也排斥不属于自己群体的其他人;③ 与西方研究多认为第三世界酒吧是西方的“文化飞地”,消费者通常是西方人或接受过西方教育的本地精英,其他本地人被隔绝在外不同,宁波老外滩的酒吧呈现出一种中国消费者“反隔离”西方消费者的现象。