数字化地图制图要素分类编码

数字化地图是地理信息系统建设的主要数据来源之一。数字化地图数据与地理信息数据的一致化,是地理信息系统建设,也是数字地图数据规范化的一项重要任务。实施地理信息系统数据工程时,人们往往在数字地图上对"地理信息要素"分类与代码进行工艺性扩展,没有有效区分数字地图制图要素与地理信息要素,从而导致不同的地理信息系统,形成不同的地理信息要素分类编码体系。本文认为,在本体论意义上,地图制图要素与地理信息要素是不同层面的概念。因此,本文根据功能特征,把数字地图制图要素划分为两类,一类是纯粹的地图制图要素,一类是G IS要素,并引入虚要素概念,把要素代码划分为G IS码、伪码、虚码三种类别,以此解决数字地图要素与地理信息要素的概念冲突,实现数字地图制图要素分类编码的可操作性,达到数字地图数据与地理信息数据一致化的目的。本文同时举例说明了符合地理空间信息要素分类代码标准要求的数字地图制图要素的分类编码方法。

Discussion on the System of Digital Mapping Element Classification and Codes

Nowadays geographical data working in GIS is mostly from digital map.The classification and encoding for the mapping elements on the digital map are very significant to building GIS,so the digital map data must be coincident with the geographical data which share GIS.The mapping elements are not equivalent to the geo-information features,or geo-information feature elements.The mapping elements and geo-information features are on different levels ontologically.To encode for the mapping elements,we must tell the difference of classification and codes for digital mapping elements from the geo-information feature's as well as give a system and encoding method of digital mapping elements which follows the geo-information feature's classification and codes.In the paper,the digital mapping elements are divided into two categories including "pure mapping elements" which are a set of mapping elements minus geographical feature elements,and "GIS′ elements" which are a set of mapping elements intersect the the geo-information feature elements;the concepts of virtual element,pseudo code and virtual code are introduced for the co-operation to the relations between the mapping elements and the geo-information features.The principle to design the classification and encoding method for the mapping elements on digital maps in the paper is to carry out the national standard of specifications for feature classification and codes of geo-information in the stage of digital mapping.The maneuverability of the classiication and encoding for the mapping elements in the paper is flexible and efficacious.The paper gives an example of the image from the mapping elements to the geographical features as well.