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基于傅里叶级数的等高线网络渐进式传输模型

刘鹏程1,艾廷华2,杨敏2   

  1. 1. 华中师范大学城市与环境科学学院
    2. 武汉大学资源与环境科学学院
  • 收稿日期:2011-08-08 修回日期:2011-11-09 出版日期:2012-04-25 发布日期:2012-04-25
  • 通讯作者: 刘鹏程

The Progressive Transmission Model for Contour based on Fourier Series

  • Received:2011-08-08 Revised:2011-11-09 Online:2012-04-25 Published:2012-04-25

摘要: 矢量地图渐进式传输的关键技术是建立连续的多尺度表达模型,并在服务器端将地图数据组织成线性结构。本文利用傅立叶级数对要素表达的多尺度特性,将傅立叶级数的参量引入到等高线要素的渐进式传输中:研究了地图尺度与曲线傅立叶展开项数的对应关系,并以此在服务器端建立了曲线多尺度表达的傅立叶描述子模型;客户端通过网络传输依次得到不同地图尺度的傅立叶描述子分量并进行曲线要素的重构,实现等高线要素渐进式的传输和表达。该模型的应用具有两大特点,其一,在网络传输的是由曲线要素提炼出来的特征向量而不是坐标数据,能起到了数据有效压缩的作用;其二,能够实现无极尺度的地图要素的表达。

Abstract: The key technology of progressive transmission for vector map is the successive multiple representations of spatial data to form the map data to line-structure organization in the server. The paper aims at vector contour data offering a new progressive transmission model based on Fourier series which has the properties of multiple representations. The corresponding relation between map scale and the number of Fourier series expanded-item is discussed, and the Fourier descriptor model for curve with multi-scale representation can be built with the relationship on the server site. The Fourier descriptor components for different map scale will be available gradually and curves will be rebuilt with them on the browser site, so the progressive transmission and representation for contours can be achieved. The actual application of model has two main characteristics. First, what is transmitted in the network is feature vectors extracted from curves, which played a important role in data compression, rather than coordinate data of curves; second, continuous map scale representation can be achieved with the model.