Fourier-based multi-scale representation and progressive transmission of cartographic curves on the internet

ABSTRACT

Automatic generation of multi-scale representations from the same spatial data source has been the research focus in map generalization for a long time. Based on the Fourier technique, this paper proposes a continuous, multi-scale representation model for progressive transformation of cartographic curves on the Internet. In our method, all the curves, whether closed or open, are depicted as periodical functions which are further expressed as Fourier series. The convergence degrees of the Fourier series are explored for different kinds of curves, and truncating frequencies are derived based on the similarity between the original and reconstructed curves. Using information theory and the Radical Law in cartography, the relationship between map scales and Fourier frequencies is established. Based on the proposed multi-scale model, we also introduce the principles and implementation of a progressive transmission method. Our method is evaluated using the contours from a topographic map. The results show that our model is a valid approach to multi-scale representation of cartographic curves.     

中国地图藏南地名的表示

该文针对1958年之后,中国地图上西藏南部有一片地区只标志寥寥无几地名的历史状况,以中国地图上藏南地区编制方法的历史状况为纽带,搜索相关历史事实,重现1958年针对藏南地区地图问题引发的两国交流,认清地图对于国家领土主权确认的重要性,推动标注藏南地区地名标注工作的进行。     

近百年中国、北半球和南半球气温内在结构比较（I）

气温气候资料是一个含有月、年、十年、百年等时间尺度的分形客体．大尺度上是冷暖之分,而每个冷（或暖）又分为较小尺度上的冷暖,形成层次结构．利用它的子波变换的尺度α－时间位置ｔ０表述,可以构造出分段线性一维映射动力系统,这个映射表征气候的层次结构,反映气候变化的突变点时间位置的规律和标度不变性．文中讨论了构造一维动力映射的基本原理,并以中国气温为例进行了验证．     

国家新版1：50000地形图制图技术设计与实践

国家新版1：50 000地形图制图工程是国家1：50 000数据库更新工程主要任务的有效延伸和重要补充,它基于最新的1：50 000地形数据库,采用数据库驱动制图技术,实现了地形图制图数据的快速生产与建库。本文在对现状和需求分析的基础上,重点介绍开展制图工程的技术方法、工艺流程、成果特点等内容。     

Automated extraction of hydrographically corrected contours for the conterminous United States: the US Geological Survey US Topo product

The US Topo is a new generation of digital topographic maps delivered by the US Geological Survey (USGS). These maps include contours in the traditional 7.5-min quadrangle format. The process for producing digital elevation contours has evolved over several years, but automated production of contours for the US Topo product began in 2010. This process, which is quite complex yet fairly elegant, automatically chooses the proper USGS quadrangle, captures the corresponding 1/3 as grid points from the national elevation data set (3D Elevation Program), and adjusts elevation data to better fit water features from the National Hydrography Dataset. After additional processing, such as identifying and tagging depressions, constructing proper contours across double-line streams, and omitting contours from water bodies, contours are automatically produced for the quadrangle. The resulting contours are then compared to the contours on the original (legacy) topographic map sheets, or to the 10-m contours from the original map sheets. Where the elevation surface used to generate the contours has been derived from the previously published contours for a quadrangle, the generated contours match the legacy contours quite well. Where newer elevation sources, such as lidar, originate the elevation surface, generated contours may vary significantly from the previous cartographically produced contours due to more accurate representations of the surface, and less reliance on cartographic interpretation.     

基于GIS的城市规划用地定级研究——以辽宁沿海产业基地为例

本文以辽宁(营口)沿海产业基地一期用地规划为例,根据自然条件、环境条件、社会条件等多个因素建立一套用地定级指标体系。采用GIS强大的分析功能综合分析总体规划区范围内三种用地(居住用地,商业用地,商业办公用地)的土地等级,结合ESRI的ArcObject组件和VS.net平台建立用地定级的计算平台,以便快速进行定级结果的计算。为城市规划、管理、经营提供定量的分析指标。     

全国1:200 000数字地质图（公开版）空间数据库

全国1：200 000数字地质图空间数据库是基于目前中国唯一的、实测的、全国性的1：200 000区域地质调查成果,由全国多家单位共同完成的全国性基础地质学空间数据库之一。数据库在空间上包含1 163幅1：200 000地质图数据,覆盖整个国土范围的72%,包含MapGIS和ArcGIS两种格式,总数据量达到90 GB。数据库主要资料来源于1：200 000区域地质调查报告和地质图及矿产图,原始资料时间跨度从20世纪50年代中期到90年代初期。全国1：200 000数字地质图（公开版）空间数据库通过国家级验收,数据完整性、逻辑一致性、位置精度、属性精度、接缝精度均符合中国地质调查局制定的有关技术规定和标准的要求,质量优良可靠。全国1：200 000数字地质图空间数据库是国家空间数据的重要组成部分,为国民经济信息化提供数字化空间平台,为国家和省级各部门进行区域规划、地质灾害监测、地质调查、找矿勘查、宏观决策等提供信息服务。     

使用AutoCAD等软件快速绘制宗海图技术研究

绘制宗海图是海域使用论证工作的重要组成部分。文章研究使用AutoCAD等软件的基本方法和技巧,重点描述界址点的快速生成、画点和编号、直角坐标系转化成经纬度格式、AutoCAD布局成图以及确定精确比例尺等方法,以期高效快速绘制符合国家标准的宗海图。     

“天地图”市级节点地名地址数据建设的研究

结合＂哈尔滨市大比例尺基础测绘＂项目及＂城市基础地理信息调查＂项目所获取的地名地址数据,通过研究该类数据的概念模型、基本属性项,以及几何表达规则,阐述＂天地图＂市级节点地名地址数据的建设、获取方法等内容。