地形模型的多分辨率简化与压缩   总被引：2，自引：1，他引：1  

赵占杰  张军  蒋涛 《测绘科学》2005,30(2):73-75

在地形的三维表达中 ,海量的三维数据在显示、存储、传输等方面存在着很多困难。为了解决这些困难 ,本文提出了一种基于渐进简化的多分辨率几何简化与压缩方法。通过该种方法 ,复杂的地形模型能够很好的被简化成适于LOD连续表达的方式 ,并且在简化基础上的数据压缩可使地形模型的存储量减少、绘制速度增加、网络传输效率提高 ,其结果能够胜任地形模型在网络上的渐进传输  相似文献   

江苏省通讯网络系统及远程终端的建立   总被引：1，自引：0，他引：1       下载免费PDF全文

周曾奎  陈必云  韩正国  何浦桥  冯民学  单云健 《气象》1995,21(1):23-27

  相似文献   

北斗卫星通信在强震动台网数据传输中的应用     

徐硕  崔建文  王暾  施伟华  韦海盛  周勇  卢爱军 《地震地磁观测与研究》2013,(5):258-265

北斗卫星系统是中国正在实施的自主研发、独立运行的卫星定位与通信系统.因其具有短报文通信功能,进行相应的软硬件开发,可以用于传输包括烈度在内的强震动台网观测数据.通过北斗卫星传输烈度速报的性能测试和在芦山7.0级大地震中的实际应用效果,对北斗卫星系统目前在强震动台网数据传输中的应用方式和效能进行介绍.  相似文献   

新疆尼勒克、巩留县交界6.0级地震测震应急流动台站架设及经验探讨     

袁顺  王宝柱  冯磊 《内陆地震》2013,27(2)

对新疆尼勒克、巩留交界6.0级地震测震应急流动台站的架设工作进行总结,针对应急流动台站的台址勘选、仪器设备的安装架设形式及数据实时传输等方面进行分析,总结经验,发现不足.期望对今后的地震现场应急流动测震台站的安装架设起到一定的参考作用.  相似文献   

Reconstruction of groundwater levels to impute missing values using singular and multichannel spectrum analysis: application to the Ardabil Plain,Iran     

Majid Taie Semiromi  M. Koch 《水文科学杂志》2013,58(14):1711-1726

ABSTRACT

Groundwater-level time series often have a substantial number of missing values which should be taken into consideration before using them for further analysis, particularly for numerical groundwater flow modelling applications. This study aims to comprehensively compare two data-driven models, singular spectrum analysis (SSA) and multichannel spectrum analysis (MSSA), to reconstruct groundwater-level time series and impute the missing values for 25 piezometric stations in Ardabil Plain, northwest Iran. The reconstructed groundwater-level time series are assessed against the complete observed groundwater time series, while the imputed values are appraised against the artificially created gap values. The results show that both SSA and MSSA demonstrate a solid competency in imputation and reconstruction of groundwater-level data. However, depending on the spatial correlation between the piezometers, and the most suitable probability distribution function (pdf) fitted to the time series of each piezometer, the performance may vary from piezometer to piezometer.  相似文献   

Web-based visualization of large 3D urban building models     

《International Journal of Digital Earth》2013,6(1):53-67

Adaptive rendering of large urban building models has become an important research issue in three-dimensional (3D) geographic information system (GIS) applications. This study explores a way for rendering web-based 3D urban building models. A client–server hybrid rendering approach is presented for large 3D city models, stored on a remote server through a network. The approach combines an efficient multi-hierarchical building representation with a novel image-based method, 3D image impostor generated on demand by a remote server. This approach allows transferring complex scenes progressively while keeping high visualization quality. We also evaluated the rendering and data transferring performance of the proposed approach.  相似文献   

Three-dimensional trees for virtual globes     

《International Journal of Digital Earth》2013,6(10):789-810

One of the problems in virtual globes technologies is the real-time representation of vegetal species. In forest or garden representations, the low detailed plants produce a lack of realism. Efficient techniques are required to achieve accurate interactive visualisation due to the great number of polygons the vegetal species have. This article presents a multi-resolution model based on a geometric representation of vegetal species that allows the application to perform the progressive transmission of the model, that is, the transmission of a simple representation followed by successive refinements of it. It has a hardware-oriented design in order to obtain interactive frame rates. The geometric data of the objects are stored in the graphics processing unit and, moreover, the change from one approximation to another is obtained by performing mathematical calculations in this graphics hardware. The multi-resolution model presented here enables instancing: as many vegetal species as desired can be rendered with different levels of detail, while all of them are accessing the same geometric data. This model has been used to build a real-time representation of a not imaginary scenario.  相似文献   

Web2.O环境下基于布鲁克斯方程的地图信息传输模型     

赵晶辉  尹章才  张世伟  李彦鹤  周沂  吴迎霞 《测绘科学》2011,36(6):164-166

各向地图信息传输模型是传统地图信息传输理论在Web2.0时代的延伸与发展,对提升现代地图学的价值具有重要意义.本文通过分析Web2.0地图的特点和相关工作,研究地图制图模式及其相应的地图信息传输模型,引入信息生态学和布鲁克斯方程,重点探索了基于Web2.0地图的各向地图信息传输模型,利用信息学的布鲁克斯方程对Web2....  相似文献   

基于三维激光扫描技术的超高压输电线路巡线技术研究     

王永波  盛业华 《测绘科学》2011,36(5):60-61,59

本文将三维激光扫描技术应用于超高压输电线路的检测与维护中。与传统的线路检测与维护方法相比较,三维激光扫描技术提供了一种方便、快捷、高效的三维数据获取手段,在此基础上,方便地计算超高压输电线路维护过程中所需的各项参数,如档距、高差、弧垂、导线的相间距离等。一方面,可以有效地论证输电线路的设计方案是否合理;另一方面,也可以合理确定故障频发地段,为电网的安全稳定运行提供了可靠的技术保障。  相似文献   

Transmission and visualization of large geographical maps   总被引：1，自引：0，他引：1  

Liqiang Zhang  Liang ZhangYingchao Ren  Zhifeng Guo 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(1):73-80

Transmission and visualization of large geographical maps have become a challenging research issue in GIS applications. This paper presents an efficient and robust way to simplify large geographical maps using frame buffers and Voronoi diagrams. The topological relationships are kept during the simplification by removing the Voronoi diagram’s self-overlapped regions. With the simplified vector maps, we establish different levels of detail (LOD) models of these maps. Then we introduce a client/server architecture which integrates our out-of-core algorithm, progressive transmission and rendering scheme based on computer graphics hardware. The architecture allows the viewers to view different regions interactively at different LODs on the network. Experimental results show that our proposed scheme provides an effective way for powerful transmission and manipulation of large maps.  相似文献