针对江苏某高速公路改扩建工程构建全球导航卫星系统(GNSS)工程控制网并进行外业观测,对观测数据进行检核计算,分析三维无约束平差和二维约束平差结果.结果表明:GNSS工程控制网内、外符合度好,网形设计良好,成果质量可靠.

针对南京市明城墙本体安全状况监测系统需要定期进行野外数据采集和分析工作的现状,本文首先进行了常规光电仪器测绘方案的不适用性分析,然后介绍了全球定位系统(GPS)静态定位(静态GPS)技术的主要优势及工作原理等,最后提出了应用静态GPS技术对南京市明城墙本体进行定期位移监测方法,并对其监测数据进行汇总分析,结果表明,变形最大值为11.1mm,平均值为3.3mm,变化速率极大值0.55mm/d,平均速率为0.12mm/d,均未达到报警值.

为了确定南京市明城墙本体安全状况需定期进行野外沉降数据采集和分析工作.通过对常规建筑物沉降监测方法进行对比分析,给出沉降监测方案,布设监测点,并采用二等水准测量方法对南京市明城墙分7段共计33个监测点进行监测.对监测数据进行汇总分析的结果表明,全段沉降监测变形最大值-5.3 mm,平均值-4.5 mm,变化速率极大值-0.020 mm/d,平均速率-0.012mm/d,均未达到报警值.

For the needs of digital earth development and solving many global problems,a new discrete global grid systenm-DQLLG (degenerate quadtree latitude/longitude grid) was put forward,which was based on WGS-84 ellipsoidal facet.The hierarchical subdivision method,characteristics and grid column/row coordinate system were detailed.The Latitude/Longitude coordinate,area and side length of multiresolution meshes on different subdivision levels were calculated.Then the changes of mesh areas and side lengths were analyzed and compared that with spherical DQLLG.The research indicates that the DQLLG had many excellent features:uniformity,hierarchy,consistency of direction,extensive data compatibility and so on.It has certain practicality for Global GIS in the future.

This paper introduces the technical requirement of high-rise construction settlement observation in the first place,then introduces settlement observation plan of the office building of Police Center of Tongzhou District of Nantong City.It focuses on the analysis of settlement observation data.The result shows that point ZL08 is the least stable,ZL02,ZL06,ZL07 points are next to it,ZL05 is the most stable point from the point of view of a single point,but the settlement value of all points

This paper firstly introduces the conventional requirement of observing construction subsidence,puts forward the technical design of Xingyuan-Hexie Mansion subsidence observation in Tongzhou District of Nantong city,focuses on the analysis of the resulting data of subsidence observation,which proves that CJ 3 is the least stable,CJ 4 is the most stable,and the subsidence of all observation points is within 1 mm.The mansion is stable in subsidence in the observation period,conforms to the requirement of subsidence accuracy.The authors propose that the observation be carried on according to subsidence observation technical plan in order to monitor the future stability of the construction.

针对目前海洋环境数据的多源、异构特点,分析海洋环境数据共享的现实需求,探讨海洋多源环境数据集成与共享的技术难点。基于当前分布式网络技术,提出海洋环境数据分布式共享方法和实现手段。通过建立海洋多源环境数据数字化共享系统平台,实现多源海洋环境数据的实时集成与共享,证明相关技术的可行性。

In order to resolve the defects in translating efficiency or precision between the traditional spherical grids and longitude/latitude coordinates,a new translating algorithm is presented in this paper.Firstly,the partition principle and encoding rules of the degenerate quadtree grid on sphere were analyzed.Then,the definition of row & column of DQG units was given and a fast translating algorithm between DQG code and longitude/latitude coordinates was designed in details.In the end,efficiency analysis by comparing experiment was done between this algorithm and other three traditional algorithms,i.e.QTM,ZOT,and ETP algorithms.The results illustrate that time consume of this algorithm is only 53%,39%,and 7% to that of three traditional algorithms by dealing with 1 million grids and the half-grid error produced by QTM is avoided in this algorithm.

In this paper, a new modeling method of global discrete grid based on the spherical degenerate quadtree is described. Our approach starts with a new partition method, called Degenerate Quadtree Grid (DQG), and an encoding scheme of the corresponding grids is presented. Next, the adjacent characteristics of DQGs in different positions are analyzed. Then, an adjacent searching algorithm of DQGs is given in details. The experiment and analysis are carried out with the global terrain data, GTOPO30. The results illustrate that: (1) the global discrete grid based on the spherical degenerate Quadtree is seamless, hierarchical, and regular over the whole Earth, and it has the same simple geometrical structure as Longitude-Latitude Grid; (2) the geometrical distortion of DQG cells is stable and astringency with the partition level increasing; and (3) the efficiency of adjacent searching in this model has been improved 100 times and 30 times respectively relative to the traditional Bartholdi Algorithm and Decomposing Algorithm. The results are good and receivable.

Adjacent search is the basis of spatial operations, such as spatial aggregation, index, query, and dynamic dilatation, and has become one of the key problems in the global discrete grids researches. In order to overcome some deficiencies in adjacent search based on the traditional latitude/longitude grid or quaternary triangular mesh (QTMs), a new partition method, called degenerate quadtree grid, and the corresponding grid code scheme are presented in this paper. Firstly, the adjacent characteristics of DQGs in different positions are analyzed. Then, an adjacent searching algorithm of DQGs is given in details. Finally, the experimental analysis is developed and the results demonstrate that the efficiency of adjacent search in this algorithm has been improved by 100 times and 30 times respectively relative to those of traditional Bartholdi algorithm and decomposing algorithm.

To overcome the deficiency in global terrain modeling of both Longitude-Latitude Grid and Quaternary Triangular Mesh(QTM),bilinear-polynomial interpolating method is selected to get the elevation of DQG(Degenerate Quadtree Grid) nodes,the efficiency analyzing and algorithm of digital elevation modeling are given in details.In the end,experiment and analy-sis are implemented with the GTOPO30 data of USGS.The results show that the DEM grids number is about 2/3 of both Lon-gitude-Latitude Grid and QTM at the same level,and the effect of visualization operations(zooming in,zooming out and crui-sing and so on) are good.

To overcome the deficiency in managing and operating the global data of both Longitude-Latitude Grid and Quaternary Triangular Mesh(QTM),a new discrete global grid——Degenerate Quadtree Grid(DQG) is put forward,and its tessellating principle and coding rule are presented.Then,its geometrical distortion is calculated and analyzed in details.The experiment results show that the DQG has not only simple geometrical structure,but stable geometrical distortion as well.