中国地壳运动观测网络基准站重力场变化的海潮负荷信号改正问题

利用最新的全球海潮模型（Csr3．0，Fes95．2，Tpxo2和Csr4．0）和原有的Schwiderski海潮模型以及中国近海海潮数据和标准地球模型负荷格林函数，采用直接褶积积分方法研究了中国地壳运动观测网络25个基准站重力固体潮观测中的海潮负荷效应问题，计算了 8个主要潮汐波的负荷振幅和相位，构制了北京和上海等10个台站重力负荷随时间变化函数。     

Performance of different TEC models to provide GPS ionospheric corrections

The existence of a worldwide international GPS service (IGS) permanent network of dual-frequency receivers makes the computation of global ionospheric maps (GIMs) of total electron content (TEC) feasible. The GIMs computed by the IGS Associate Analysis Centers on a daily basis and by other kinds of forecast GIMs, which can be computed from, for instance, the international reference ionosphere (IRI) model, and the GPS broadcast models in the navigation message, can be applied to a broad diversity of fields, for instance as, navigation and time transfer.In this context, the performance of different kinds of models are presented in order to determine the accuracy of the different GIM. This is carried out by comparison with the TOPEX data that provides an independent and precise (at the level of few TECU) vertical TEC determination over the oceans and seas. Thus, the obtained accuracies, in terms of global relative error, ranging from 54% corresponding to the GPS broadcast model, to about 41% corresponding to IRI climatological model, and to less than 30% corresponding to GPS data driven models.     

二维和三维电子地图的空间认知差异研究

讨论了二维和三维电子地图在空间认知特点、空间认知模式和空间认知效果方面的差异。与纸质地图相比,二维电子的地图的空间认知具有动态性、交互性以及制图和读图过程的模糊化等特点,三维电子地图的认知效率更高、认知维度和深度更广。空间认知模式方面,二维电子地图类似于"阅读式",而三维电子地图则类似于"观看式"。二维电子地图对位置、距离、方向等空间格局的认知效果较好,而三维电子地图对目标、形状等空间对象的认知效果较好。     

综合性军事地理图集内容框架设计

本文分析了军事地理环境和要素随着现代战争发展所发生的重要变化,阐述了综合性军事地理图集图组设计和内容选题的基本原则,提出了综合性军事地理图集表达内容框架.     

古地图与现代空间数据的河道变迁研究——以清代潇河为例

潇河是汾河的第二大支流,清代河道变迁频繁.本文利用清代山西地方志中的舆地图和现代空间数据,结合历史文献记载与实地考察,研究了潇河河道变迁最为剧烈的时期--清代近300年间的变迁过程,复原了不同时段的面貌,并对变迁原因进行了分析.认为在气候变干的大背景下,河道变迁的原因主要有两个:一是潇河及其支流泥沙含量大,造成旧河道的...     

Applying GPR-amplitude wave maps and Am-scans as a semi-quantitative approach to the internal structure of sediments

In this work we analyse the applicability of amplitude grid maps to the routine of geological surveys by means of GPR (ground penetrating radar). Although amplitude grid maps have been commonly used in archaeological surveys, their use in geological prospecting (including the detection of voids and determination of the internal geometry of sedimentary bodies) is not widespread. The direct analysis of GPR-profiles permits the analysis of geometrical features and other qualitative aspects that can be related to changes in EM properties. Aspects such as changes in the density of the banded disposition in radargrams, loss of reflector definition or higher scattering in particular zones of the profiles can give useful, though non-quantitative, information. The GPR wave-amplitude is a qualitative measurement of magnetic properties that can be processed as a semi-quantitative layout. The main differences observed in changing wave amplitude are related to the surveyed materials and their geometry. These changes produce variations in the relative wave amplitude or vertical wave-phase changes related to differences in the propagation velocity, the attenuation factor, the reflectivity and the geometry of the materials. Maps based on the lateral correlation between profiles (C-scans) or the lateral correlation of wave amplitudes along the same profile (as a tomography or Am-scans) permit the analysis of these changes. Variations in amplitude grid maps or Am-scans are related to (i) geometrical changes of surveyed materials, (ii) changes in the dielectric constant, and (iii) changes in the potential penetration depth (higher attenuation in particular zones of a profile) than can be correlated to the type, state or clay content of subsoil materials. Direct analysis of exposures helps to constrain interpretation using the geometrical features in radargrams resulting from the geological structure. In the same way, analysis of geometrical features in radargrams, together with time-slices of C-scans, can be used to determine the areal distribution of changes in the subsoil and approach the changes in EM properties. An example with parallel profiles and different devices, constrained by means a broadband multifrequency EM survey is shown.     

"电纸"服务平台的研制

从GIS平民化服务的角度,研制一种"电纸平台",即把纸质地图和电子地图的展现方式融为一体,使其优势互补,在老百姓应用和享受地理信息成果时,既能像纸质地图一样,一目了然,使用方便,又能具有电子地图海量数据库的支持,灵活方便展现、更新和网络化操作.     

基于MSORQ-Tree的三维景观地图表示

针对WebGIS多尺寸三维景观地图数据处理问题,提出了一种高速数据索引结构MSORQ-Tree。根据该索引的算法,得出移动WebGIS景观图,将该索引和其他索引进行性能比较。结果显示,基于金字塔分割规则的区域,进行分割四叉树所获取的MSORQ-Tree高速索引可有效处理WebGIS中海量景观地图数据。     

环境空气质量系列专题地图制图方法研究

环境与发展是当今世界共同关注的重大问题。目前我国经济正处于高速发展时期,随着经济社会的快速发展和城镇一体化进程的加快,空气污染问题日趋严重,对人体健康造成很大伤害,因此环境保护的重要性日益突出。本文通过建立环境质量空间数据库,利用地理信息软件ArcGIS为基础平台,将环境空气质量监测数据与地理空间位置进行地理匹配,利用地理信息可视化技术,实现环境空气质量监测数据中各主要空气污染物的浓度时间分布的可视化表达,制作环境空气质量专题地图,有助于有效地从海量监测数据中发现有价值的信息,为环境保护部门提供决策参考依据。     

General Principles for Automated Generation of Schematic Network Maps

Usually, a street map contains various types of detailed information and appears to be crowded. As a result, to many users, a street map looks complicated and is not easy to read and follow. In fact, to a certain degree, too much detail makes the map uninformative and noisy. The London tube map, called a schematic or topological map in some literature, has often been cited as an excellent example of a simplified map. Algorithms have been developed by researchers to automate the generation of schematic maps for road networks. However, it is found that there is still a lack of defined general principles and here four general principles have been formulated for schematisation – the Principle of the Preservation of the Topological Relationship; the Principle of the Preservation of the Main Structure of the Line Network; the Principle of Relativity in Position; and the Principle of Relativity in Length. The first two are the principles of preservation: these two should never be violated. The last two are principles of relativity: it is very desirable to keep these two intact unless there is an absolute need to violate them.