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基于代数结构的地形图制图模型

李霖1,朱海红2,贺 彪2,王红2,邱俊武2,于忠海2   

  1. 1. 武汉大学资源与环境科学学院
    2. 武汉大学
  • 收稿日期:2010-02-24 修回日期:2010-05-11 出版日期:2011-06-25 发布日期:2011-06-25
  • 通讯作者: 李霖

Topographic cartographic model based on algebraic structure

  • Received:2010-02-24 Revised:2010-05-11 Online:2011-06-25 Published:2011-06-25

摘要: 随着海量地理信息的累积,生产高质量地图的过程对地理信息系统技术提出了重大的挑战,基于地理数据库驱动的地图制图方法,是应对此挑战的一个有效方法,但到目前为止,还没有从过程建模方面对这种方法进行系统地深入研究。本文根据地图表达的特点,将地理信息抽象表达为二元结构,即反映语义属性及空间位置属性的地理要素和要素间空间关系;利用代数结构形式,在地理空间数据库和地图中分别构建表达地理信息的地理要素空间和地图要素空间;地理要素空间中的空间关系是基于欧式空间原理建立的,而地图要素空间中的空间关系则是用视觉模型来刻画。据此,提出了以地理要素为对象的从地理要素空间向地图要素空间转换的制图模型。通过定义符号单元同核变换将目前制图过程中的符号化过程从面向地理要素类层延展到面向地理要素实例层,克服了统一符号化过程不能同时满足共性和特性要求的矛盾;定义的地理要素有效移位变换可使地图制图过程更加流畅,减少中间人工干预过程。此模型明确了制图过程中提高自动化制图程度的关键技术,在原理上揭示了制图过程中地理信息转换的机理,为数据库驱动的制图系统功能设计提供了良好的理论基础。

Abstract: With an accumulation of abundant geo-information, production of high quality maps for presenting the geo-information challenges the capacity of GIS. Geo-database-driven cartography emerging as an effective means to produce maps from geo-databases, have not been scrutinized in a systematic way, especially in terms of modeling the process of map-making. A cartographic model being put forward in this paper characterizes the process of map-making by a transformation from geographical space to map space based on an algebra structure, and provides with a theoretical foundation and operational guideline for this merging technology. According to cartographic presentations of geo-data in topographic maps, geo-information is abstracted into two elements: geo-features and spatial relationships between the features, and further structured in form of algebra into two algebraic spaces; Geo-Feature Space in a geo-databases world and Map-Feature Space in a map world respectively. The spatial relationships in Geo-Feature Space are modeled by Euclidean space and the spatial relationships in Map-Feature Space are calibrated by the visual cognitive mechanism. The cartographic model is built up by transforming geo-features into map-features which is restrained by the consistent spatial relationships in the two spaces. By defining an equivalent-kernel transform among symbol cells, map symbolization based on feature classes is extended into that based on feature instances, fitting cartographic representations being both specified and universalized. With defining the displacement transform for geo-features, the process of map-making proceeds more smoothly, reducing being intervened to a large extent. This model through the two transforms, articulates the key issue for automating map-making and reveals the mechanism of the transformation of geo-information from geo-databases to map representation, providing a guideline for better design of functionality of GIS.