地图数字化的数学基础及在世界地图数字化中的应用

地图作为地图数据库、地理信息系统、遥感等最基础和最重要的数据源 ,其精度问题已成为各学科共同关注的问题。本文提出了地图数字化的数学基础 ,详细讨论了两种常用的数据采集模型 :并以世界地图数字化系统为实例 ,介绍了系统的构成 ;并重点讨论了破译地图数学基础的原理和方法。     

一种电子地图要素和属性的组织方式

针对电子地图数据的组织效率问题,提出了一种易于操作及更新的数据组织方式。探讨了地图要素及其属性数据的组织特点,并描述了一种更加柔性的电子地图数据模型,最后使用一个具体实例验证地图数据模型的可行性。     

对我国数字城镇建设的几点思考

我国城镇化快速发展迫切需要在全国大中小城市和小城镇加快实施信息化战略,建设具有中国特色的“数字城镇”。本文从“数字城镇”技术构成出发,分析了我国“数字城镇”发展现状及其面临的主要科技问题,提出要加强对“数字城镇”数据平台、综合信息服务平台、业务应用平台构建等关键技术问题的研究,以从整体上提升我国城镇信息化的水平。     

中国古典叙事文学的时空叙事数字模型研究——以《李娃传》为例

文学制图作为一种再现文学空间的文学地理研究方法,能将历时性叙事与共时性空间进行相互映射,但是过往的实践案例往往受限于单一的研究视角,忽略了二者内部的整体性互动关系及其与外部时空的联系。为了促使文本中的线性叙事与并置空间作为整体概念而服务于当代的文学制图实践活动,本文依据巴赫金文学时空体中的历史时空、文本时空和读者时空的概念提出了一个叙事时空数字模型,并以唐传奇小说《李娃传》为文学制图实践案例,可视化再现了这个以唐长安为中心的爱情故事。在融合了计算叙事和地理叙事研究路径的基础上,本文对叙事文本所蕴含的顺序的、多维的和背景性的信息,进行了语义提取、语义的时空循环映射和“时间—时空—空间”的叙事再现,从而呈现叙事的语言线性、体验性和意义性的特征。该模型以开放的和可对话的框架帮助当代人理解古典文学叙事及其地方性历史语境,同时将拓展从宏观、微观的角度以沉浸式方式对地方（place）进行叙事的潜力。     

ArcGIS Model Builder在历史数据处理中的应用

在智慧潍坊时空大数据与云平台的建设中,需要将历史地形图数据进行数据入库。与传统的地形图人工内业数据入库处理方法相比,基于ArcGISModelBuilder技术对数据处理过程建模,对数据进行自动化处理的做法在作业中具有极大的优势。利用该工具创建了房屋、高程点、控制点等几种地物的自动化处理模型,实现了多种地形图要素的自动化处理,简化了传统的地形图入库作业流程,提高了数据处理效率。该文以潍坊市历史地形图为例,验证了该方法在保证数据质量的同时,能够有效提高数据的生产效率,为历史地形图数据的生产入库提供了切实可行的操作思路和实现工具,同时可为其他地区历史地形图数据入库工作提供参考。     

伪随机码调制的CW半导体激光雷达试制报告

本文报告一种用半导体激光器作光源,用子脉冲宽度100ns,长度为511的周期伪随机码对半导体激光器的输出作幅度调制;APD作光电检测器,高速数字信号处理器TMS320C25作信号处理的激光雷达组成方案和试作样机的实验结果。     

Development of spectral hazard maps for a proposed revision of the Indonesian Seismic Building Code

The need to revise the current Indonesian Seismic Hazard Map contained in Indonesian Earthquake Resistant Building Code SNI 03-1726-2002 which partially adopts the concept of UBC 1997, was driven among others by the desire to better reflect the potential larger earthquake disasters faced by the nation in the future. The much larger than maximum predicted Aceh Earthquake (M _w 9.0–9.3) of 2004, followed by the destruction observed during the 2005 Nias Earthquake (M _w 8.7) urgently underline to need to consider the new conceptual approach and technological shift shown in the transition of UBC 1997 to IBC 2006. This paper presents research works for developing spectral hazard maps for Indonesia. Some improvements in seismic hazard analysis were implemented using recent seismic records. Seismic sources were modeled by background, fault, and subduction zones by considering a truncated exponential model, pure characteristic model or both models. A logic tree method was performed to account for the epistemic uncertainty and several attenuation functions were selected. Maps of PGA and spectral accelerations for a short period (0.2 s) and for a 1-s period were then developed using a probabilistic approach. The maps will be proposed as a revision for the current seismic hazard map in the Indonesian Seismic Building Code.     

Automatic Sounding Generalization in Nautical Chart Considering Bathymetry Complexity Variations

Sounding acts as the main feature in a digital nautical chart as it describes the concerned marine topography for the safety of navigation. Unlike the geometry-oriented selection of point feature, the generalization of soundings for chart compiling is expected to be context-oriented, which means bathymetry complexity variations across the study region should be preserved in the sounding selection process. However, such variations are not explicitly accessible to automated systems. This paper proposes an approach that effectively analyzes and measures bathymetry complexity from sounding data, with a focus on topography variations among different regions. The presented approach first divides the exploring region into several subregions, by adopting techniques of computational geometry and graph theory. Then, the approach quantitatively measures the bathymetry complexity of the subregions from grid-based digital terrain model. Finally, a composite bathymetry complexity index integrating aspects of steepness and depth variation is developed to guide the operation of sounding selection in different subregions. Generally, when seafloor is rugged with steep slopes, the number of soundings is high. While in flatter areas, a smaller amount of soundings is retained. The potential of our approach is demonstrated by an application to a real data set.     

The influence of topography and land use on water quality of Xiangxi River in Three Gorges Reservoir region

A self-organizing map (SOM) was used to cluster the water quality data of Xiangxi River in the Three Gorges Reservoir region. The results showed that 81 sampling sites could be divided into several groups representing different land use types. The forest dominated region had low concentrations of most nutrient variables except COD, whereas the agricultural region had high concentrations of NO₃N, TN, Alkalinity, and Hardness. The sites downstream of an urban area were high in NH₃N, NO₂N, PO₄P and TP. Redundancy analysis was used to identify the individual effects of topography and land use on river water quality. The results revealed that the watershed factors accounted for 61.7% variations of water quality in the Xiangxi River. Specifically, topographical characteristics explained 26.0% variations of water quality, land use explained 10.2%, and topography and land use together explained 25.5%. More than 50% of the variation in most water quality variables was explained by watershed characteristics. However, water quality variables which are strongly influenced by urban and industrial point source pollution (NH₃N, NO₂N, PO₄P and TP) were not as well correlated with watershed characteristics.     

The digital seismometer, a modern instrument

On the basis of an analysis of the development history of seismometers, the conclusion is made that a new generation of instruments—digital seismometers—should be created. The functions of a digital seismometer and its advantages over other existing instruments are described in brief.