地形图的数字化对构建地理信息系统有十分重要的意义。借鉴面向对象的思想，提出了一种扫描地形图自动分层算法，算法先将地形图线划要素与普染区背景分离；然后把具有相同特征的像素分割成线段对象与块对象，以这些对象为最基本的分类单元；通过提取对象的颜色、形状和近邻关系等特征，建立分类标准，实现地形图的自动分层。该算法能有效克服扫描引起的颜色混淆和假彩色的影响，分层结果完整连通，从而很大程度上抑制“椒盐”现象的发生。

Digitization of topographical maps is significant for creating geographical information system. In this paper, object-oriented approach is introduced into of segmentation scanned map. The procedure is described as follows. First, linear elements and area elements are separated. Then they are partitioned into image objects which are basic cells to classify map features, not single pixels. And a set of features combining color, shape and topological are extracted from each object. Based on the features, a classification criterion is employed to perform the map segmentation. The proposed method overcomes aliasing and false colors induced by the scanning process. The results seem coherent, with name of the “salt and pepper” effects.