随着空间数据获取手段的不断丰富,新一代地理信息系统需要满足不同获取方式、不同数据格式和不同数据形式等时空数据综合可视化需求.以倾斜摄影测量为基础的城市空间三维建模,是对复杂城市物理世界实现数字化的有效解决方案.利用虚实融合技术,将真实视频数据与虚拟三维模型场景进行融合可视化,可以减少虚拟三维模型与真实物理世界时空上的差异,达到更真实的用户体验效果.动态视频数据与三维模型纹理的融合过程中,通常需要借助深度图来对相机可见性进行判断,当深度图计算精度不够高时,融合场景中会出现视频纹理断带或穿透的问题,因此,提出一种线性深度调节优化算法,该算法可以减小深度图中深度值与实际相机深度之间的误差,实现视频纹理数据与三维模型的精确融合.通过实验证明线性深度调节优化算法可以有效提高三维模型场景中视频数据动态可视化效果.

Global warming caused by massive carbon emissions poses a serious threat to the environment and human beings. Dynamic monitoring of the spatio-temporal evolution of carbon emissions is an essential way to achieve carbon reduction goals, especially in coastal areas like Guangdong Province faced with dual challenges of massive carbon emissions and rigorous reduction targets. To reveal the spatio-temporal characteristics of carbon emissions and provide a basis for further fine-grained carbon emission reduction strategies, we analyzed spatio-temporal distribution characteristics of carbon emissions in Guangdong Province at the county-level scale from 2000 to 2020. Based on the land-use data obtained from the Data Center for Resources and Environmental Sciences of the Chinese Academy of Sciences and energy consumption data from the Statistical Yearbook, the carbon emission of each county is estimated, and the spatio-temporal evolutionary features of them are explored by a series of methods of the exploratory spatio-temporal data analysis (ESTDA). The shift of spatial distribution characteristics and gravity center is further revealed with the standard deviational ellipse and gravity center migration analysis.The results reveal that the net carbon emissions increased from 6179.229 × 104 tons to 20765.723 × 104 tons during 2000–2020. The net carbon emissions of county-level administrative regions show a significant positive spatial correlation, and the spatial convergence shows a trend of first decreasing and then increasing. The spatio-temporal pattern of carbon emissions has an obvious path dependence and locked spatial features, and shows a gradually strengthening trend. The spatial distribution of carbon emissions formed a stable “northeast-southwest” pattern, and the gravity center of carbon emissions in the past 20 years has been distributed between 113.208°–113.357°E and 22.760°–22.878°N, tending slightly shifting to the northeast. The results of the study can help understand the spatio-temporal evolution of carbon emissions in Guangdong, and provide a reference for formulating effective carbon reduction policies.

为满足大范围房屋建筑承灾体高度高效调查的需求,提出了一种顾及房屋结构的建筑物高度快速自动估算方法.首先基于LiDAR点云制作区域数字高程模型和数字表面模型,获取地面和地表高程矢量点;然后利用1∶500地形图数据对房屋结构进行解析,确定房屋底部和顶端高程计算面;最后以高程计算面内点要素的高程均值作为底部和顶端高程,进而求差计算房屋高度.以广州市南沙区范围内的532栋房屋建筑对象为实验对象,该方法得出的建筑高度与不动产登记资料的实际高度误差约有84.21%在0.2 m之内,表明该方法效率高、精度可靠,能满足大范围房屋高度快速调查的需求.

数字高程模型(DEM)是进行三维地理空间分析的重要基础性数据.在地形复杂、植被茂密的山区,DEM生产精度往往较低,难以满足实际需求.文章研究了基于机载LiDAR点云的DEM生产流程,对关键生产步骤进行了分析,并利用高精度地形图控制点进行了DEM精度评价.项目测试结果表明,方法生产流程可靠、高效,生产成果精度达到0.46 m,能够满足实际应用需求.

南沙新区作为粤港澳大湾区的几何中心,在"三区一中心"的发展格局下,城市快速发展建设累积了海量多源异构地理信息数据.综合大数据、云计算、物联网等技术,基于中台的架构理念,从数据模型、存储管理、空间索引、轻量化和制图引擎等方面构建了面向南沙新区的地理信息时空数据中台,并作为智慧南沙的地理信息数据底座,挖掘当前累积的多源异构地理数据的应用价值,实现"一处建设、多处应用",为南沙新区建设提供持续全面的数据服务支撑.

In the face of the actual needs of information management of ancient and famous trees, the paper integrates mobile GIS-related technologies and develops an ancient and famous trees information management system based on mobile GIS. The system realizes the spatial distribution display, information query, attribute browsing and one map management of ancient and famous trees data. The use of the system can facilitate the development of ancient and famous trees protection, effectively improve the efficiency of tree protection information management, and promote tree information and intelligent management.

Urban expansion studies have focused on two-dimensional planar dimensions, ignoring the impact of building height growth changes in the vertical direction on the urban three-dimensional (3D) spatial expansion. Past 3D simulation studies have tended to focus on simulating virtual cities, and a few studies have attempted to build 3D simulation models to achieve the synergistic simulation of real cities. This study proposes an urban 3D spatial expansion simulation model to achieve a synergistic simulation of urban horizontal expansion and vertical growth. The future land use simulation model was used to simulate urban land use changes in the horizontal direction. The random forest (RF) regression algorithm was used to predict building height growth in the vertical direction. Furthermore, the RF algorithm was used to mine the patterns of spatial factors affecting building heights. The 3D model was applied to simulate 3D spatial changes in Shenzhen City from 2014 to 2034. The model effectively simulates the horizontal expansion and vertical growth of a real city in 3D space. The crucial factors affecting building heights and the simulation results of future urban 3D expansion hotspot areas can provide scientific support for decisions in urban spatial planning.

[目的]近年来,精密单点定位(Precise Point Positioning,PPP)技术凭借其高精度、灵活性等特点已逐渐广泛应用于精密导航定位等应用中.但随着大众用户对导航定位需求的不断增加,硬件成本已成为制约高精度卫星导航定位在大众用户中广泛使用的主要因素之一.[方法]因此本文提出了一种基于低成本单频接收机的多模非组合单频PPP模型,并基于实测单频数据进行了数据质量分析与动态定位验证.[结果]结果表明:基于本文提出的多模非组合单频PPP模型水平精度为0.1m左右,高程精度为0.3m左右.[结论]可满足大众用户车道级导航定位需求.

The rapid development of social media data, including geotagged photos, has benefited the research of tourism geography; additionally, tourists’ increasing demand for personalized travel has encouraged more researchers to pay attention to tourism recommendation models. However, few studies have comprehensively considered the content and contextual information that may influence the recommendation accuracy, especially tourist attractions’ visual content due to redundant and noisy geotagged photos; therefore, we propose a tourist attraction recommendation model for Flickr-geotagged photos which fuses spatial, temporal, and visual embeddings (STVE). After spatial clustering and extracting visual embeddings of tourist attractions’ representative images, the spatial and temporal embeddings are modeled with the Word2Vec negative sampling strategy, and the visual embeddings are fused with Matrix Factorization and Bayesian Personalized Ranking. The combination of these two parts comprises our proposed STVE model. The experimental results demonstrate that our STVE model outperforms other baseline models. We also analyzed the parameter sensitivity and component performance to prove the performance superiority of our model.

文中采用模糊数集来描述先验信息,用模糊贴近度来衡量先验信息的可靠性,给出了可信度的计算公式,将其以权阵的形式纳入参数估计中,以平衡不同可信度的先验信息在参数估计中的作用.最后通过算例分析了该算法的可行性.

结合南沙区水文遥测系统高程基准项目中三等跨河水准测量,详细阐述了基于TM30测量机器人的三角高程测量的跨河水准测量方法和施测过程,通过对仪器的改装以及测量方法的改进,实现了两台仪器间跨河视线的同时对向观测,大大减弱仪器高误差、大气折光误差、地球曲率误差等影响,可代替相应等级水准测量.

新型基础测绘对传统基础测绘提出了新的要求,本文结合广州市南沙新区地形图更新项目研究建立新型基础测绘体系下的城市大比例尺地形图更新机制.该项目迄今已连续四年完成南沙区陆域570 km2的地形图更新工作.该项目在进行期间对新型基础测绘理念、地理实体分类、多级格网划分与更新管理进行了探索与研究,项目成果验证了本文所研究的更新机制能够更加充分利用基础地理信息框架服务体系,提高更新效率,保证城市大比例尺地形图的生命活力.

无人机监测是城市违法用地和违法建设监管工作的重要手段,提高无人机影像处理效率,能够有效减轻违法建设监管工作压力.基于这一目的,本文构建了基于卷积神经网络的深度学习模型,针对城市违法建设中典型的推土区图斑进行了样本集构建和模型训练,并利用无人机正射影像进行了疑似违法建设区域的快速发现实验.实验结果表明,本文方法对于0.5 m分辨率的无人机影像数据发现率能够达到85％以上,目标发现率较高,能够为城市违法用地和违法建设监管工作提供支持.

基于城市地下金属构建物的常规物探工作过程受限于地下结构和施工环境复杂等问题,本文提出了将阵列式瞬变电磁法运用至城市地下金属构建物的探查工作中,利用地下目标体感应信号具有的矢量特性,以及发射线圈周围及后方干扰源信号在空间上呈现向前衰减,前方目标体的异常信号表现为向前增强的变化特征,大幅提高了地下金属构建物的横向分辨率.结合物理模拟及工程实例验证表明:阵列式瞬变电磁法利用多路接收装置同步接收城市地下金属构件的感应信号,对于靶区横向方位及纵向埋深的分辨能力具有良好效果,为城市地下金属管线探查和管廊建设提供了新的探测方法.

本文提出了一种识别近景摄影测量照片中的圆形标志中心的方法。对于一张照片上的标志点的提取分为手工提取和自动提取两种方式,自动提取包含粗略定位和精确提取两个阶段。该方法已应用于笔者开发的近景摄影测量数据处理软件中,结果证明在单纯背景下面自动提取具有较好的提取效果,而在较为复杂的背景下面提取效果亦可接受。

Virtual 3D city models provide important information for different aspects in a lot of domains.Up-to-dateness of and flexible access to 3D city models are of utmost importance in some situations such as emergency response.In this paper we introduce CityGML,a common information model for representing 3D urban objects and interoperable access to 3D city models over the Internet.Based on the standard GML3,CityGML covers the geometrical,topological,and semantic aspects of 3D city models.In CityGML,spatial and semantic properties of 3D urban objects are structured in five consecutive levels of detail.Throughout the paper,special focus is on the digital terrain model and building model of CityGML.