GIS环境下污水管网设计流量的快速计算

针对ＧＩＳ环境下污水管网设计问题，提出了一种快速计算管段设计流量的方法——递归方法。分析了递归的原理、链式表的建立以及递归算法的具体实现等，并以实例阐述了递归计算的各个步骤     

GIS环境下污水管网设计流量的快速计算

针对ＧＩＳ环境下污水管网设计问题，提出了一种快速计算管段设计流量的方法－递归方法。分析了递归的原理、链式表的建立以及递归算法的具体实现等，并以实例阐述了递归计算的各个步骤。     

基于广度优先的排水管网连通性分析算法设计

针对衡阳市石鼓区雨污水管网合流带来的各种问题,在对排水管网数据特征进行分析的基础上,依据定向和物探点号唯一的特征以及基于广度优先搜索的基本思想,设计并实现了基于广度优先的排水管网连通性分析算法,并将此算法应用于衡阳市石鼓区地下综合管线系统,实现了高效、科学的排水管网连通性分析,精确获取管网流动物质来源,为排水系统末端污水处理、科学化的城区污水排放规划和管理提供辅助决策支持。     

数字管网连通分析的淘汰算法与实现

本文从图论的观点出发,分析了数字化市政管网的构成和连通的特点,探索出数字化管网线路连通性分析的规律,提出了逐步淘汰算法进行连通性分析的方法。给出了基于mapbsic的实现这种算法的关键语句和注意问题。     

基于OpenGL城市大规模管网三维建模

城市管网是城市建设的重要组成部分。本文讨论了基于OpenGL的大规模城市管网三维建模技术,从介绍世界坐标系和局部坐标系的转换关系出发,重点介绍了管网的直线部分建模和管网衔接处的建模,提出了一种基于顶点混合技术来绘制管网衔接处的新算法,该算法方便高效,能产生逼真的效果,并给出了加快三维显示速度的方法,实现了城市管网的大规模实时建模。     

适用于关阀分析算法的供水管网单元-阀门图模型

关阀分析在供水管网施工中用来快速确定最佳的关阀停水方案,对于供水安全具有重要意义。在管网传统结点-边图模型的基础上,提出了优化实体数量并简洁表达拓扑结构的单元-阀门图模型。该模型是结点-边图的一种伪对偶图,它将管网内被阀门区隔形成的封闭连通区域归为顶点,将分隔两个区域的阀门作为边。设计了关断单元生成算法,从而实现单元-阀门图的构建,并提出基于该模型的高效供水管网关阀分析算法。实验表明,与基于结点-边图的传统算法相比较,结合单元-阀门图模型的新算法能够大幅度提高关阀分析效率,并且可以在多施工点情况下得出正确的关阀方案。     

排水管网系统精细拓扑模型描述与实现

针对当前排水管网拓扑模型简单、拓扑分析能力较弱的现状,提出了一种管网拓扑精细模型,改进了节点单一问题,将节点细分为多类并提出相应的拓扑规则,使之更符合管线客观模型,有利于进行空间分析。在管线和节点数据结构设计中,采用十字链表作为管网数据结构,便于管线与节点双向分析,同时建立R树索引,实现对空间数据管理。结合镇江管网地理信息系统开发实验,实现了基于改进拓扑模型的空间分析算法,结果发现本文提出的拓扑模型结构简单,易于实现,能够模拟管线排水细节,提供更多基于水务模型的空间分析类型,数据访问效率较高。     

空间格网化燃气管网风险评价

本文基于空间格网化思想,综合利用空间格网模型、城市地下燃气管网危险度分析模型和承灾体易损性分析模型,实现城市地下管线风险评价空间化、可视化。通过格网化空间分割,可以减少管段划分环节人为主观因素的影响。风险空间可视化为用户提供了事故威胁对象、位置和风险大小的空间信息,为用户风险空间认知提供形象、直观的工具,结合报表等数据实现精确又形象的风险认知,为决策者进行城市燃气管网规划、改造、运营决策提供科学依据。     

排水管网GIS数据入库与更新方法研究

在对排水管网数据特征进行分析的基础上,设计了其在排水管网GIS系统中的入库算法,对新测管网数据和历史管网数据先进行缓冲区分析确定数据更新范围,然后叠加分析并进行相应数据编辑,实现排水管网GIS系统中数据的更新。     

九、P28 地图制图学(地图学)

CH971841 GIS环境下污水管网设计流量的快速计算/孟令奎(武汉测绘科技大学)……∥武汉测绘科技大学学报.一1997,22(1).—16～20 针对GIS环境下污水管网设计问题,提出了一种快速计算管段设计流量的方法——递归算法。其原理是把污水管网这种重力流的枝状结构网络,抽象成由若干有向树构成的森林。对于每棵有向树而言,根结点表示污水处理厂,叶结点为污水收集节点,内节点(除根节点以外的节点)是污水转输节点,同时也可能是污水收集节点(当有本段流量时),树枝代表污水管道(段)。树的方向性表现在污水是从叶节点(或内节点)逐级往下游管段和节点流动,直至达到根结点。分析了链式表的建立,实例阐述了递归计算的各个步骤。图1表     

阿克苏河-塔里木河水系水质污染遥感监测与评价

 采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的 污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体 污染变化曲线,得出污染物浓度随着远离上游而增加。     

Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data

The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw.     

使用FME与VBA提取机场方格网高程数据

因受机场工程设计软件的测量数据容量限制,基于LiDAR采集、点云分类后得到的地面点云数据LAS不能完整应用于目前设计软件进行设计计算。本文通过对拟选技术方案的筛选,提出了利用FME Workbench数据处理功能,结合VBA编程获取外部方格网平面数据的方法。该方法在FME Workbench中实现了地面点云数据构建TIN、采用逐点内插方法从TIN中提取方格网高程数据、等高线生成及相应图形处理与成果输出。最终通过实际算例证明了该方法的有效性。     

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.     

Gravity Changes Before Large Earthquakes in China: 1998-2005

Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200...     

GNSS系统及其技术的发展研究

阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议.     

自动车辆定位导航系统中传感器的误差分析

对国界定位导航系统中几种常见的辅助传感器所产生的误差进行了分析，导出了不同传感器的误差模型。这些误差模型是估计车辆位置的扩展卡尔曼滤波器的基础，同时也为选择适当的传感器提供了理论根据。     

“4D”技术及其应用

介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。     

Virtual Australia: its key elements – know,think, communicate

Abstract

Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised.