Spatio-temporal GIS data model based on event semantics

There are mainly four kinds of models to record and deal with historical information. By taking them as reference, the spatio-temporal model based on event semantics is proposed. In this model, according to the way for describing an event, all the information are divided into five domains. This paper describes the model by using the land parcel change in the cadastral information system, and expounds the model by using five tables corresponding to the five domains. With the aid of this model, seven examples are given on historical query, trace back and recurrence. This model can be implemented either in the extended relational database or in the object-oriented database.     

Correction on effect of Earth’s oblateness in inversion of GPS occultation data

By using observed CHAMP orbit ephemeredes and MSISE-90 dry air model and regarding the earth as a sphere and an ellipsoid respectively, phase delays are simulated and the simulated data are retrieved under different schemes. The comparison between the inverted temperature profiles and the model temperature profiles shows that by inverting observed data, we will get temperature results with large errors if the effect of Earth’s oblateness is omitted. The correction method is proved to be effective because the temperature errors decreased obviously with this method.     

Forward simulation of gravity for crustal structure of Xiachayu-Gonghe profile in eastern Tibetan plateau

The crustal structure of Xiachayu-Gonghe geophysical profile in eastern Tibetan plateau is simulated with Bouguer anomaly corrected for sediments and lithosphere. The forward simulation shows that the thickness of upper crust in eastern Tibetan plateau is about 20 km, and the density is 2.78×103kg/m3. The bottom interface of middle crust changes from 30 km to 40 km, the density of middle crust is 2.89×103kg/m3. The materials with low density of 2.78 ×103kg/m3 exist in middle crust, and those with high density of 3.33 ×103kg/m3 exist at the bottom of middle crust between Wenquan and Tanggemu. The density is 3.10 ×103kg/m3 in lower crust. The shallowest depth of Moho interface is about 56 km, and the deepest one is about 74 km, the undulation of interface is large, the deep Moho is located in Xiachayu, Chayu, Nujiang, and Wenquan. The crustal density of eastern Tibetan plateau is larger than that of central section; the low velocity layers are located in middle crust and bottom in eastern Tibetan plateau and at the bottom of the upper crust in the central plateau.     

资源三号数据在省域主体功能区监测方面的应用

当前国家以及各地区主体功能区区域规划已经完成,如何对规划后的主体功能区进行监测,是当今主体功能区监测面临的重大课题。资源三号卫星数据为主体功能区监测提供新的数据源。本文以资源三号卫星数据为数据源,开展主体功能区监测应用,并建立主体功能区监测平台,用于主体功能区监测与地物提取。     

基于MAPX的MapInfo数据空间索引的建立

空间索引技术在诸多领域均有十分重要的研究意义,目前已存在很多种建立方法,各有优缺点。MapInfo软件功能强大易用,但不具有建立空间索引这项功能,因此本文主要研究在MAPX基础上建立一种适合MapInfo数据的空间索引。该方法主要针对车载导航系统中的一个基本算法地图匹配来进行研究。采用单层规则格网建立的空间索引并对其进行改进,在第一步划分的基础上再次进行网格划分,建立起两级交错式划分方法的空间索引。通过实验表明该方法使实时路段搜索过程的实现简单、方便、明了。     

基于遥感影像的土地动态变化监测

土地利用/覆盖变化是目前研究全球及区域环境的一个重要领域,在城镇化加速的今天,城镇的土地利用格局也发生了飞速的变化。本文通过其一研究区内的Landsat TM遥感影像进行处理,获取了2007~2016年10个时相土地利用/覆盖信息,通过不同的预测模型对监测到的数据进行处理及比较,根据相应的最优预测方法预测了2017~2019年南昌市各土地类型的数据,由此研究并探讨了南昌市土地利用/覆盖的时空格局变化。     

基于夜间灯光数据的南京城镇用地提取

针对多时相夜间灯光影像无法直接对比的问题,该文提出了一种基于不变目标进行不同年份不同卫星夜间灯光数据的校正方法。在系统校正多时相夜间灯光数据的基础上,应用支持向量机分类算法提取城镇用地信息,并分析1992—2013年南京城镇扩张动态变化规律。结果表明:该数据校正方法可以有效减少年际夜间灯光影像之间的异常差异,提高不同年份数据间的连续性和可比较性;支持向量机分类算法提取的4个样区城镇用地信息总体精度和Kappa系数平均值分别为88.35%和0.56,能够准确反映区域城镇发展的实际情况;1992—2013年南京城镇经历先缓慢后快速的扩张过程,主城区在1992年城镇基础上往四周扩张,并沿长江及南北交通走廊发展。     

基于代理技术的多源GIS服务访问控制方法设计与实现

GIS门户用于整合各种来源的GIS服务,并为用户提供统一的GIS服务访问入口.访问控制是GIS门户建设的重要技术基础,现有方法是通过授权机制,授予用户相应GIS服务的访问权限.由于不隐藏原始服务地址,即使用户被取消授权,但因其已获取过原始服务地址,依然可绕过GIS门户访问相应的GIS服务,GIS门户无法对已注册GIS服务的访问情况进行控制.通过代理技术可以有效地隐藏原始服务地址,但由于GIS门户的特殊性,使用现有的代理服务器不仅配置复杂,而且要与GIS门户的授权机制相结合,实现难度大.为解决以上问题,本文基于代理技术的思路,自主研发实现了一种多源GIS服务访问控制方法,采用对注册GIS服务的原始服务地址的隐藏机制,以及建立与之对应的代理服务地址的映射关系,使得被授权用户只能访问代理服务地址,进而实现GIS门户中对注册GIS服务的访问控制.基于此设计实现的SuperMap iPortal注册服务访问控制模块,支持对注册的多源GIS服务进行代理,提供统一的代理服务根地址,方便对多源GIS服务进行统一使用、管理和维护.     

Image Pose Estimation Based on Procrustes Theory

This paper has established a high-precision hierarchical estimated pose parameters of image. Firstly, we select corresponding three image points of 3D points which constitute the largest area in image as a base, in order to estimate the depth and translate information; then based on the above method, we obtain the scale parameter of camera exterior information. And finally, the topic is transformed to a problem of estimating rotation relationship by vector, using Procrustes theory to obtain the best estimate of the angle elements of exterior parameters. The method can effectively solve problems which depth and coupling pose parameters cannot deal with. Experimental results show that this method of determining position and orientation parameter estimation model is of briefness, easy convergence and it can also achieve higher parameter estimation accuracy than the direct projection matrix factorization.     

Error analysis of the 3D similarity coordinate transformation

The 3D similarity coordinate transformation with the Gauss–Helmert error model is investigated. The first-order error analysis of an analytical least-squares solution to this problem is developed in detail. While additive errors are assumed in the translation and scale estimates, a 3 × 1 multiplicative error vector is defined to effectively parameterize the rotation matrix estimation error. The propagation of the errors in the coordinate measurements to the errors in the estimated transformation parameters is derived step-by-step, and the formulae for calculating the variance–covariance matrix of the estimated parameters are presented.