基于道路矢量数据的路口地理实体面图元提取

地理实体数据是实景三维数据中的重要组成部分,路口实体在城市实景三维中有着重要作用,当前路口实体面图元的提取是通过人工查找路口位置并在路口位置处手动构建路口面,这种提取方式容易漏掉路口位置且有人工编辑工作量较多的问题。为准确定位路口位置且在路口位置处高效构建路口面图元,本文设计了一种基于道路矢量数据的路口地理实体面图元的提取方法,通过对道路面数据构建不规则三角网,分析不规则三角网(TIN)在路口处的特点,准确定位出路口位置,并在路口处自动构建路口面图元。本文基于湖南省基础测绘道路矢量数据,对基于道路矢量数据的路口地理实体面图元提取方法的有效性进行验证,实验结果表明,该方法路口定位准确率达97.5%,路口面构建较为准确,可以有效缩短路口实体生产周期,研究结果可以应用于其他条带状交叉口实体类的定位和构建。

GIS环境下面对象可视化技术与方法

阐述了地理信息系统环境下面对象可视化问题 ,在分析面对象可视化类型和绘制方法的基础上 ,设计了面符号图元 ,并对绘制面符号的有关算法和思路进行了讨论 。

Process of back pressure deep drawing with solid granule medium on sheet metal

The experimental die apparatus of the solid granules medium forming on sheet metal was designed and manufactured.Typical parts,such as conical,parabolic,cylindrical and square-box-shaped components,were successfully trial-produced as well.According to the analysis of the changing trends of the cross-section shape and the wall thickness during the process,it can be found that the shape of the free deformation zone of the sheet metal,which is the most critical thinning area,can be described as an approximately spherical cap.According to this forming feature,back pressure deep drawing technology with solid granules medium on sheet metal was proposed to restrain drastic thinning at the bottom of the part through the joint friction effect of solid granules medium,the back pressure tringle and the sheet metal.Therefore,the deep drawing limit of the sheet metal is significantly improved.In order to fabricate thin-walled rotary parts with great drawing ratio and complex cross-sections,a finite element model based on the material property test of the solid granules medium was established to optimize the scheme of the back pressure deep drawing.The effects on the forming performance of sheet metal from back pressure load and the approach of blank holding control were analyzed through this model.

Generating Graphic User Interface of Web Applications Using Source Code Generator Based on Dynamic Frames

This paper deals with a problem of application generation together with their Graphic User Interface （GUI）. Particularly, the source code generator based on dynamic frames was improved for more effective specification of GUI. It＇s too demanding for the developers to have specification of the application that contain all physical coordinates and other details of buttons and other GUI elements. The developed solution for this problem is based on post-processing of generated source code using iterators for specifying coordinates and other values of graphic elements. The paper includes two examples of generating web applications and their GUI.

Phase equilibria in Ni-Ti-Ta ternary system

Phase diagrams of two isothermal sections of the Ni-Ti-Ta ternary system at 1000 and 1200℃in a full composition range were determined by X-ray diffraction and electron probe microanalysis.The experimental results indicated a ternary compoundτphase with low solid solubility and composition ranges of(16.3-22.4)at.%Ta,(15.9-24.1)at.%Ti and(58.5-60.0)at.%Ni at 1000℃.The two terminal solid solutions(bcc-(Ta)andβ-Ti)formed a continuous solid solution at 1000 and 1200℃.A certain amount of Ti can dissolve into Ni-Ta intermetallic compounds near the Ni-Ta side,with the highest value of 21.9 at.%observed in the Ni;Ta compound at 1000℃.

Modeling diurnal variation of ground thermal radiance images using energy balance model and endmember composing technique

Modeling and analyzing dynamic changes of land thermal radiance scenes play an important role in thermal remote sensing. In this paper, the diurnal variation of ground surface thermal scene is mainly discussed. Firstly, based on the land surface energy balance equation, the diurnal variation of land surface temperatures （LSTs） over bare land covers were simulated by an analyt- ical thermal model with second harmonic terms, and the diurnal LST variation of vegetation canopy was simulated using the Cupid model. Secondly, normalized difference vegetation index （NDVI）, normalized difference water index （NDWI）, and ratio resident-area index （RRI） were used to evaluate the endmember abundance of four land cover types including vegetation, bare soil, impervious and water area, which were calculated from IKONOS visible and near infrared （VNIR） bands. Finally, the thermal radiance scenes at various times and view angles were modeled based on the linear-energy-mixing hypothesis. The re- suits showed that the simulated daily LST variations for vegetated and bare surfaces are correlated with the measured values with a maximum standard deviation of 2.7℃, that land thermal radiant textures with high-resolution are restored from the lin- ear-energy-mixing method, and that the information abundance of the scene are related to the distribution of land cover, the imaging time, and the view angle.

Transformation Method of Exterior Orientation Angular Elements Obtained via Position and Orientation System Under Gauss-Kruger Projection Coordinate System

Data obtained via airborne position and orientation system （POS） is in WGS 84 global geocentric reference frame, while the national coordinate reference system for topographic mapping in China is generally Gauss-Kruger projection coordinate system. Therefore, data obtained via a POS must be transformed to national coordinate system. Owing to the effects of earth curvature and me- ridian deviation, there are some errors in the process of angle transformation from roll, pitch, and heading （φ,θ,ψ） obtained directly via a POS to the attitude angles of images （φ,ω,κ） needed in photogrammetry. On the basis of effect theories of earth curvature and meridian deviation on exterior orientation angular elements of images, a method using a compensation matrix to correct the transformation errors from attitude angles obtained via the POS to exterior orientation angular elements of images is proposed in this paper. Moreover, the rigorous formula of the compensation matrix is deduced. Two sets of actual data obtained via a POS AV 510, which are different in scale and terrain, are selected and used to perform experiments. The empirical results not only indicate that the compensation matrix proposed in this paper is correct and practical but also show that transformation accuracy of exterior orientation angular elements obtained via the POS based on compensation matrix is relevant to the selection of vertical axis （a projection of central meridian） of Gauss-Kruger projection coordinate system; the proper vertical axis should be the Gauss-Kruger projection of the central meridian of projection zone in which the survey area locates. However, the transformation accuracy of exterior orientation angular elements is irrelevant to the choice of origin of coordinate system; it is appropriate that the origin of coordinate system locates at the center point of the survey area. Moreover, transformation accuracy of exterior orientation angular elements achieved based on the compensa- tion matrix deduced in this paper is higher than that obtained via the existing POS processing software.