清华山维EPSEM房产空间管理系统转换亿图软件的技术实现方案

介绍了当前福州市更新房地产信息管理软件亿图软件,由存量房产测绘成果转换到亿图软件带来的问题,提出了利用C#及AutoCAD的二次开发工具ObjectARX开发技术解决这些问题的方法并进行了总结。     

倾斜影像的量测方法研究

随着“数字地球”“数字城市”的提出,能够快速获取空间数据基础信息成为当今急需解决的问题之一。传统的航空摄影测量主要是对地物顶部信息的获取,而对侧面信息获取比较困难,因此倾斜航空测量技术成为国内外快速发展起来的一门高新技术。本文主要论述了基于倾斜影像量测的几种方法,并对以后量测方法的发展趋势进行了说明。     

铁路测量中坐标系的建立与转换

在铁路测量中,长度投影变形要求小于2．5cm／km。但是由于铁路为典型的线性工程,通常横跨多个投影带,因此采用国家标准3。带难以满足铁路测量精度要求,本文通过分析高斯投影长度变形,提出分段建立独立坐标系的方法,控制长度投影变形,满足精度要求,最后介绍利用GlobalMapper软件实现两个独立坐标系的转换。     

森林资源调查的便携式野外声控记录技术研究

随着精准林业的提出,林业数字化、自动化已经成为林业发展的必然趋势。为了解决森林调查中因人为因素而导致的记录偏差问题,本文介绍一种基于PDA,并将GPS、蓝牙、声控等技术进行综合集成的森林资源连续清查样地调查应用系统的设计和实现,并对其系统结构、工作原理、硬件构成、软件设计等进行论述。该系统的开发和实现把野外调绘和数据采集融为一体,将会改变传统的野外调查方式,实现数据采集自动化,并将大大提高外业和内业的工作效率。     

洪水淹没分析中的自适应逐点水位修正算法

洪涝灾害损失评估是防洪减灾科学决策的基础,其中洪水淹没分析是准确提取洪水淹没范围、水深及历时等灾情信息的关键。洪水淹没分析主要采用数字高程模型数据,由于DEM的格网分辨率与高程精度有限,常出现异常的洼地或平地,导致难以可靠地计算每个格网点处的流向,而传统方法采用统一高程的洼地填平处理又使得容易出现洪水演进过程中复杂起伏地形水面爬坡以及平坦地形水位断流的问题,为此提出顾及流速和淹没时间的自适应逐点水位修正算法,即在DEM坡面流模拟的基础上,根据洪水水流特性、地形、边界变化、水流速度、水深变化以及淹没点的淹没时间,计算水位修正值,对洪水演进过程中每个格网点的水位进行修正,采用多种地貌类型的DEM数据进行试验,证明洪水演进的淹没范围、水深及历时的实时计算结果准确可靠,可为快速评估灾害损失与防洪决策服务提供更为科学的依据。     

城市地下综合管网建设模式——以天津市为例

本文以天津市为例,分析了目前城市管网管理中存在的问题,提出了切实可行的综合管网系统建设模式,设计了有效的管网数据模型,并利用地理信息系统和三维数字仿真技术构建了城市地下综合管网管理系统,在实践中取得了良好的应用效果。     

The integrated spatial databases of GeoStar

GeoStar is the registered trademark of GIS software made by WTUSM in China. By means of the GeoStar, multi-scale images, DEMs, graphics and attributes integrated in very large seamless databases can be created, and the multi-dimensional dynamic visualization and information extraction are also available. This paper describes the fundamental characteristics of such huge integrated databases, for instance, the data models, database structures and the spatial index strategies. At last, the typical applications of GeoStar for a few pilot projects like the Shanghai CyberCity and the Guangdong provincial spatial data infrastructure (SDI) are illustrated and several concluding remarks are stressed.     

Analysis of spatial clustering optimization

Spatial clustering is widely used in many fields such as WSN (Wireless Sensor Networks), web clustering, remote sensing and so on for discovery groups and to identify interesting distributions in the underlying database. By discussing the relationships between the optimal clustering and the initial seeds, a clustering validity index and the principle of seeking initial seeds were proposed, and on this principle we recommend an initial seed-seeking strategy: SSPG (Single-Shortest-Path Graph). With SSPG strategy used in clustering algorithms, we find that the result of clustering is optimized with more probability. At the end of the paper, according to the combinational theory of optimization, a method is proposed to obtain optimal reference k value of cluster number, and is proven to be efficient.     

Data model and visualization of 3D city landscape based on integrated databases

Data acquisition and modeling are the two important, difficult and costful aspects in a Cybercity project. 2D-GIS is mature and can manage a lot of spatial data. Thus 3D-GIS should make the best of data and technology of 2D-GIS. Construction of a useful synthetic environment requires integration of multiple types of information like DEM, texture images and 3D representation of objects such as buildings. In this paper, the method for 3D city landscape data model and visualization based on integrated databases is presented. Since, the data volume of raster are very huge, special strategies (for example, pyramid gridded method) must be adopted in order to manage raster data efficiently. Three different methods of data acquisition, the proper data structure and a simple modeling method are presented as well. At last, a pilot project of Shanghai Cybercity is illustrated.     

Spatial decision support applications based on three-dimensional city models

The basic mathematic models, such as the statistic model, the time-serial model, the spatial dynamic model etc., and some typical analysis methods based on 3DCM are proposed and discussed. A few typical spatial decision making methods integrating the spatial analysis and the basic mathematical models are also introduced, e.g. visual impact assessment, dispersion of noise immissions, base station plan for wireless communication. In addition, a new idea of expectation of further applications and add-in-value service of 3DCM is promoted. As an example, the sunshine analysis is studied and some helpful conclusions are drawn.