地图目标移位的面目标变形约束及其处理

The displacement operator is an important and still a hot topic in map generalization. In the generalization product, symbols must be unambiguous and easily perceived and readily understood, which makes space competition among features an important obstacle in the process of map objects displacement. Space conflict between objects, through propagation process, may be spread and more objects may drift into it. In order to maintain symbols equilibrium and spatial relationship between objects, some unimportant symbols or parts of symbols should be distorted under constraints according to visual graphic resolution thresholds to figure out space competition among map features. Three constraints including position, legibility and characteristics are important for the maintenance of symbols equilibrium and spatial relationship, which are discussed in this paper. The skeleton is introduced to represent area objects figure characteristic, in which an area object can be separated to parts hierarchically according to their importance in the construction. Then, the finite element method is applied to the map objects’ displacement and distortion, in which a strategy for the parameters of finite element method is discussed. Supported by the National Science Foundation of China (No.40401050), the Leading Academic Discipline Project of Shanghai Educational Committee (No.J50104), the Science Foundation of Shanghai Education Department (07ZZ09).     

Continuity markers as an aid for children in finding the peripheral continuity of world maps

ABSTRACT

Many map readers, including both children and adults, find it difficult to determine where they would be located along the edge of a world map after crossing that edge. Different types of markers have long been drawn close to the map’s edge – for example, in an atlas – to help map readers identify the map upon which they will find themselves if that edge is passed. In this study, a method similar to that used to show the continuity between maps in an atlas has been tested to determine whether continuity markers can also be used to help map readers find a world map’s actual peripheral continuity. The study involved children between the ages of 10 and 13 years and showed that continuity markers do help children determine the map’s actual peripheral continuity, in combination with a lesson that describes how to find the actual peripheral continuity of a world map. This article, therefore, concludes that continuity markers for world maps can be a useful part of map design that clarifies how the edges of a world map fit together for children who have learned to use this tool.     

The development and analysis of quasi-linear map projections

Map projections are an essential component of coordinate systems used in applications such as surveying, topographic mapping, and engineering, and care needs to be taken to select ones that minimize distortion for each case. This article explores the selection process for near-linear features on the surface of the Earth and derives limits for the extent of a project that can be projected within specified distortion tolerances. It is then demonstrated that a multifaceted set of projections of the Earth may be used to extend this concept to the mapping of features such as highways and railways that are quasi-linear but do not exactly follow a standard geometrical line (a great circle or a small circle) on the surface of the Earth. A continuous, conformal coordinate system may be derived in such situations, extending to indefinite length and applicable over a swath of several kilometers width, but it cannot be extended to cover situations with extensive variations in height. Instead, the Snake Projection is analyzed, and it is shown that this can be used to develop continuous (non-zonal) projected coordinate systems for major engineering projects extending for hundreds of kilometers and having extensive height ranges. Examples are shown of the application to railway projects.     

地图符号拓扑紧凑性和异质性信息测度

地图拓扑信息的准确测度,对于多比例尺地图表达、制图自动综合等具有重要意义。针对现有地图拓扑信息测度指标多单方面关注地图符号邻接方式的多样性或邻接关系的紧凑性,未能全面刻画地图符号拓扑空间格局与结构特征的问题,提出地图符号拓扑信息的构成包括拓扑结构紧凑性信息和拓扑结构异质性信息两部分。在此基础上,定义了地图符号拓扑结构紧凑性和异质性信息量,提出其计算方法,将其分别用于中国成都市、瑞典耶夫勒市和美国旧金山市的部分路网,结果表明该方法能较为准确地描述路网的拓扑结构。     

Quantitative relations between spatial similarity degree and map scale change of individual linear objects in multi-scale map spaces

Quantitative relations between spatial similarity degree and map scale change in multi-scale map spaces play important roles in map generalization and construction of spatial data infrastructure. Nevertheless, no achievements have been made regarding this issue. To fill the gap, this paper firstly proposes a model for calculating spatial similarity degrees between an individual linear object at one scale and its generalized counterpart at the other scale. Then psychological experiments are designed to validate the new model, taking four different individual linear objects at five different scales as test samples. The experiments have shown that spatial similarity degrees calculated by the new model can be accepted by a majority of the subjects. After this, it constructs a formula that can calculate spatial similarity degree using map scale change (and vice versa) for individual linear objects in multi-scale map spaces by the curve fitting method using the point data from the psychological experiments. Both the formula and the model can calculate quantitative relations between spatial similarity degree and map scale change of individual linear objects in multi-scale map spaces, which facilitates automation of map generalization algorithms for linear features.     

雪龙船南北极考察走航图的制作

“雪龙船南北极考察走航图”是采用新编《系列世界地图》制作的成果。极地考察是一项全球性的重要的科学活动,雪龙船是我国目前唯一的极地科学考察破冰船,表现雪龙船极地科学考察航行路线的走航图,将成为我国南北极考察活动与社会公众沟通的新形式和重要媒介之一。     

儿童电子地图特征及基本设计原则

儿童电子地图是一种儿童电子读物,必须集趣味性与知识性为一体,并充分兼顾儿童的读图和识字能力。本文根据对当前比较有影响的几个地图网站上的电子地图的实际操作并兼顾儿童的生理与心理特征,提出了儿童电子地图的内容设置、特点、功能和设计原则。     

地形图的确定性与不确定性

地形图是地球科学研究中的基础资料。本文阐述了地形图上等高线、线性要素、面积要素的确定性与不确定性,即除非比例尺为1∶1,否则等高线并不真正具有“等高线上点的高度相等”的意义,这一不确定性特征,这种不确定性随着比例尺、地貌类型等的变化而变化。线性要素、面积要素的确定性与不确定性问题与之类似。     

序列比例尺地图缩编中建筑物综合算法

针对在序列比例尺地图综合中较少涉及如何构建面向大规模工程化应用的、顾及不同居民地分布特征的建筑物综合算子的现状,该文以广州地区为例,从纵横两条线开展。纵向上,对建筑物随尺度变换依次从单幢房屋向建筑群组、建筑区域、街区转换过程中涉及的综合操作和关键算子进行研究;横向上,主要研究同一尺度转换过程中顾及空间分布特征的建筑物多边形分组合并方法,基于"分而治之"的思想对城区、城中村、郊区等三种典型样本设计综合算子。该文设计的算子兼顾了适用性和效率,在广州地区序列比例尺空间数据库快速构建中得到了应用。     

一种新的地图数据检索方法及其应用软件

本文提出了一种新的实用地图数据检索方法——“放大镜”式地图数据检索,建立了相应的软件系统,并讨论了该方法的数学基础、软件的特点,还给出了应用实例。     

土地利用现状图扫描符号的自动提取与识别

土地利用现状图扫描符号的自动提取能节省人力财力物力。本文采用地图代数和人工神经网络的方法进行扫描现状图符号的自动提取和识别。首先根据图例建立用于特征匹配的符号模板库,然后使用加壳变换和蜕皮变换进行点状符号和线状符号的分离,并使用Canny算子平滑符号,再通过人工神经网络的训练进行色彩聚类而实现符号分割。定义多重相似度,实现符号的预分类识别,在此基础上计算加权距离再次识别。最后采用加壳变换连接断点并提取骨架线对这些断线进行连接,形成完整的线状符号。实验表明,本方法的正确率达到90%以上。     

车载移动测量系统在大比例尺地形图数学精度检测中的应用

研究了车载移动测量系统在大比例尺地形图数学精度检测中的应用。首先在小范围内对其进行了相关试验,得到其有效性后,对某市全市域的地形图进行了抽样检测;对车载移动测量检验与常规方法检验在外业数据采集、内业数据处理及存储量等几方面进行了比较,分析了车载移动测量检验方法的优劣性,为提高测绘质检效率提供了一种新方案。     

互联网地图搜索引擎视觉质量的模糊评价与可视化分析

本文采用用户分类调查和模糊评价方法,对互联网地图搜索引擎案例的视觉质量现状进行综合评估和横向比较,并对评语细化差异进行分类分用户的多变量可视化分析.总体评价结果为"良",国外比国内略好.其中,各指标权重表明,颜色配置、界面构图和道路表达对互联网地图的视觉效果起首要的决定作用.最后,基于用户为中心和跨学科协同的理念,提出...     

面向嵌入式GIS应用的地图标注算法设计与实现

本文提出的一种基于栅格的地图标注算法,应用于嵌入式G IS系统中电子地图标注的自动配置。该算法将地图中各要素标注的自动配置作为一个统一的整体来对待,从而避免了一般局部标注配置算法可能终止于一个局部最优解的缺点。通过实例证明,利用该算法进行电子地图中标注的自动配置,数据计算量小,通用性强,速度较快。     

国家基础地理信息数据库在西部地区县(市)挂图项目中的应用及技术分析

西部地区县 (市 )挂图工程是以国家测绘局现有的基础地理信息数据库、高分辨率卫星影像数据及其他多种测绘资料为基础 ,采用基于地理信息系统的全数字计算机桌面制图新工艺 ,设计制作科学性强、艺术性高、制作精良的高技术地图产品 ,充分展现地图学理论、制作技术与我国经济发展的水平。本文以分析西部地区县 (市 )挂图项目中的国家基础地理信息数据库的应用范围及数据适宜性评价为基础 ,提出了数据库应用于地图制图的方案 ,总结了若干技术问题及方法。     

基于信息熵的面状要素在地图综合中的量测方法分析

目前,信息熵理论被广泛用于地图信息含量的量测,但对于地图综合的信息量分析评价的研究还不多。介绍信息熵理论及地图综合中的几何信息熵概念,并将其运用到面状要素的地图综合信息量量测中。在实例分析中,通过将不同地类分类,较好地反映了不同地类在地图综合中信息量的变化,说明用几何信息熵表征面状要素在地图综合中的信息量是可行的。并在之后进一步提出几何信息熵的加权理论,为进一步研究提供方向。     

基于Geodatabase建立数字地质图数据库的方法与实践

本文简要介绍了Geodatabase空间数据模型的特点及优势,列举了创建Geodatabase数据库通用的三种方法,并以1:5万却勒塔格幅地质图为例,重点探讨了用CASE工具建立基于Geodatabase数字地质图数据库的具体过程。研究表明,用这种方法建立地质图数据库可以将面向对象方法很好地应用于空间数据库的设计中,大大缩短了建库时间,提高了建库效率,并使商用关系型数据库的技术和优势得到充分发挥。     

基于MapGuide的校园电子地图应用平台的设计与实现

基于Autodesk公司开源版Mapguide为平台,设计了江南大学蠡湖校区校园电子地图应用平台,并在该应用平台上设计和实现了基于RFID电子标签的校园车辆查询功能.     

对立统一在地图学中的体现和意义

辩证法简要地确定为对立统一的学说。文中论述地图投影、地图比例尺、专题制图、地图概括、地图现势性的演化和地图制图过程等地图学中的对立统一问题,说明对立统一在地图学中普遍存在,从而在哲学层面上阐释地图学发展演进的动力机理。     

LBS导航认知地图服务系统设计与实现

科技发展改变了电子地图制作和使用环境。本文在分析传统大数据量地图形式在LBS中的应用缺陷后,提出了符合用户需求和移动终端条件的认知地图可视化方案,这种不同于传统制图综合原则制作的认知地图能有效缓解目前在LBS应用中存在的地图数据与屏幕大小的矛盾,适应了移动环境下用户的多行为状态和终端硬件特点。