共查询到19条相似文献，搜索用时 171 毫秒
1.
根据测绘产品的现状和实际迫切需求,结合多年的案例经验,对测绘产品的三维可视化系统所需的硬件和软件系统进行了研究和开发。详细分析了系统的技术和市场。笔者经过多年的开发和实施了多个成功案例,实践证明测绘产品的三维可视化系统得到了用户和市场的认可,产生了客观的经济效益。 相似文献
2.
由于缺乏相应的多尺度表达与索引机制,灾害模拟数据的三维动态可视化存在难以实时进行、渲染效果差、模式单一等问题。鉴于此,将泥石流灾害模拟数据与虚拟地形环境相结合,重点研究了泥石流灾害模拟数据实时在线发布与多尺度三维动态可视化方法。设计了网络服务总体框架体系,并重点探讨了多尺度数据组织、索引、动态表达等关键技术;选取案例区域研发原型系统,并开展了分析实验。结果表明,该方法能满足泥石流灾害在线实时三维动态可视化要求,也可根据用户对精度和流畅性的偏好与需求,选择相应尺度进行可视化表达。 相似文献
3.
4.
激光强度作为地面三维激光扫描仪特有的测量值,在现有三维激光扫描仪中并没有得到有效利用.鉴于此,文章从理论上推导了激光强度值的影响因素,根据强度值的影响因素提出了一种强度值的改正方法,并通过实验对理论模型进行了验证分析.实验结果表明:本文提出的改正方法能较好地对强度值进行改正,对相关的硬件制造和应用具有一定的价值. 相似文献
5.
6.
7.
8.
针对网络三维虚拟地球中对大范围、高密度复杂三维模型高效绘制的要求,设计了面向GPU绘制的三维模型数据组织结构。在此基础上,提出了面向GPU绘制的三维模型纹理烘焙和多尺度可视化方法。基于开放式虚拟地球集成共享平台GeoGlobe进行了实验,比较了传统绘制方式和基于GPU的绘制方法在可视化效果和效率上的区别。实验表明,本文提出的方法在保持三维模型特征条件下能有效提高其绘制效率。 相似文献
9.
面向虚拟地球的三维气象场可视化方法 总被引：1，自引：0，他引：1
《武汉大学学报(信息科学版)》2016,(12)
三维气象场是一个多维变化的环境,可视化是研究其内在规律的重要方法。针对三维气象场的全球范围、多维多尺度、海量数据等特征,提出了基于体元对象的数据模型和多级体元索引机制,并在此基础上设计了面向三维气象场的可视化方法,包括基于箭头模型的矢量场可视化方法和改进后的基于三维纹理映射体绘制的标量场可视化方法。最后基于虚拟地球平台进行了可视化和时空检索分析实验。实验验证了该方法的可行性和有效性。 相似文献
10.
11.
12.
Wumeng Huang 《International Journal of Digital Earth》2018,11(9):939-955
3D city models, which are important items of content on the virtual globe, are characterized by complicated structures and large amounts of data. These factors make the visualization of 3D city models highly dependent upon the performance of computer hardware. Thus, achieving the efficient rendering of 3D city models using different hardware performance levels represents one of the key problems currently facing researchers. This paper proposes a time-critical adaptive visualization method that first estimates the possible rendering time for each model according to the data structure of the model in addition to the CPU/GPU performance of the computer. It then dynamically adjusts the rendering level for each model based on the results of an estimation of the rendering time to ensure that the final scene can be completed within a given time. To verify the effectiveness and flexibility of this method, it is applied using different computers. The results show that the adaptive visualization method presented in this paper not only can adapt to computers with different levels of performances but also demonstrates an obvious improvement in the time estimation precision, visual effects, and optimization speed relative to existing adaptive visualization methods. 相似文献
13.
An assessment of coefficient accuracy in linear regression models with spatially varying coefficients 总被引：1，自引：3，他引：1
The realization in the statistical and geographical sciences that a relationship between an explanatory variable and a response
variable in a linear regression model is not always constant across a study area has led to the development of regression
models that allow for spatially varying coefficients. Two competing models of this type are geographically weighted regression
(GWR) and Bayesian regression models with spatially varying coefficient processes (SVCP). In the application of these spatially
varying coefficient models, marginal inference on the regression coefficient spatial processes is typically of primary interest.
In light of this fact, there is a need to assess the validity of such marginal inferences, since these inferences may be misleading
in the presence of explanatory variable collinearity. In this paper, we present the results of a simulation study designed
to evaluate the sensitivity of the spatially varying coefficients in the competing models to various levels of collinearity.
The simulation study results show that the Bayesian regression model produces more accurate inferences on the regression coefficients
than does GWR. In addition, the Bayesian regression model is overall fairly robust in terms of marginal coefficient inference
to moderate levels of collinearity, and degrades less substantially than GWR with strong collinearity. 相似文献
14.
《制图学和地理信息科学》2013,40(3):140-153
A hybrid system that integrates two-dimensional (2D) GIS and three-dimensional (3D) visualization has been developed to provide unique solutions to application domains where traditional 2D GIS and 3D visualization cannot alone provide a solution. In this paper, we focus on three key issues in realizing such an integrated system, including large-scale terrain rendering, 2D and 3D combination display (for example, rendering 2D GIS layers in 3D space), expanding traditional 2D GIS analysis functions into a 3D environment, and visualizing 3D geographical data. A generic framework is developed to integrate 3D visualization with various types of 2D GIS, such as commercial GIS software, open source GIS software and spatial databases. A prototype 2D and 3D hybrid system that seamlessly integrates 2D GIS (developed with ArcEngine) and 3D rendering engine (developed with DirectX) is then developed based on the framework. In this hybrid system, 2D and 3D data are viewed within the same scene. Multiple 2D GIS layers are overlaid on the base terrain using a Level of Detail (LOD) model. Advanced query functions, data accessing, data management and spatial analysis, which are executed in the traditional 2D GIS, are provided to users in a 3D environment by continuously transforming information between the 2D GIS subsystem and the 3D subsystem. The 3D data are organized and displayed by Keyhole Markup Language (KML) and textured 3D models in the COLLAborative Design Activity (COLLADA) format. The prototype demonstrates that this hybrid system has effectively addressed the three key issues identified above and that it can seamlessly integrate 2D GIS and 3D visualization. The hybrid system has great potential to be employed in many application domains, such as urban planning, landscape design and environmental decision making, among others, to enhance the 3D design capability and facilitate public participation in the planning, design and decision-making process. 相似文献
15.
相机的外方位元素是摄影测量立体重建的重要参数。通过3维直接线性变换,利用3维控制场可以很容易地确定相机的外方位元素。文中提出并推导了在2维控制场的条件下,利用2维直接线性变换和共线方程之间的关系分解出相机外方位元素的实用算法。实验结果验证了该算法的正确性和可行性。 相似文献
16.
基于大比例尺航空立体相对提出昆山市政府及周边建筑群的建模方案,采用VirtuoZo数字摄影测量系统提取地面要素信息,在IMAGIS三维可视化地理信息系统下进行三维模型重建和编辑,在此基础上形成由CAD、GIS、三维影像数据集成的城市三维可视化处理方法,实现对三维场景进行实时漫游,并将漫游过程录制成动画,在Premiere中完成音频视频合成制作,形成最终多媒体产品。 相似文献
17.
Transect-based three-dimensional road modeling and visualization 总被引：3，自引：0，他引：3
LIQingquan TANGLuliang ZUOXiaoqing LIHanwu 《地球空间信息科学学报》2004,7(1):14-17
On the basis of the study on road elements and the existing three-dimensional road data models, this paper puts forward the transect-based road modeling, resolves the modeling of the simplest road with two road transects, and fulfils the visualization of the road. OpenGL is applied as the tool of visualization. The map texture technology, LOD algorithm and dynamic multi-differentiating texture technology are of benefit to the construction of 3D road GIS, and improve the speed of roaming and effective visualization. This paper also disusses the combination of 2D digitall road map and 3D road scene, and the dynamic response between them. Finally, on the basis of the research on the transect-based road model, this paper develops the three-dimen-sional road geographic information system called virtual road ( VRoad ), which not only supplies road designers with a set of tool which can turn the designed 2D road data into 3D road and the high road assistant function area in computer, but also supplies the road management with a set of tool which can realize the road real time and interactive roaming, high-efficiency management. 相似文献
18.
19.
A collinearity diagnosis of the GNSS geocenter determination 总被引：4，自引：4，他引：0
The problem of observing geocenter motion from global navigation satellite system (GNSS) solutions through the network shift approach is addressed from the perspective of collinearity (or multicollinearity) among the parameters of a least-squares regression. A collinearity diagnosis, based on the notion of variance inflation factor, is therefore developed and allows handling several peculiarities of the GNSS geocenter determination problem. Its application reveals that the determination of all three components of geocenter motion with GNSS suffers from serious collinearity issues, with a comparable level as in the problem of determining the terrestrial scale simultaneously with the GNSS satellite phase center offsets. The inability of current GNSS, as opposed to satellite laser ranging, to properly sense geocenter motion is mostly explained by the estimation, in the GNSS case, of epoch-wise station and satellite clock offsets simultaneously with tropospheric parameters. The empirical satellite accelerations, as estimated by most Analysis Centers of the International GNSS Service, slightly amplify the collinearity of the $Z$ geocenter coordinate, but their role remains secondary. 相似文献