地形特征约束的等高线群渐进式简化方法

为保留等高线群简化过程中的地形特征信息，研究了一种等高线群渐进式简化方法。首先，从等高线数据中提取地形特征点及地形特征线；将提取的地形特征点和特征线作为约束条件予以量化，并作为控制变量；再依据渐进式图形简化的思想，利用控制变量对等高线上的非特征点、特征点、特征线及其关联的弯曲进行渐进式取舍，从而实现等高线群的动态简化。实验结果表明，该方法能够有效地保持地貌形态特征，同时提高了简化过程的智能化程度。

Progressive Simplification Methods of Contour Line Group Constrained by Topographic Feature

To preserve topographic feature during simplifying of contour line groups, a progressive simplification method is proposed. Firstly, topographic feature points and lines are extracted from contour lines according to expert rules. Secondly, both the extracted topographic feature points and lines as constraints are quantified as control variables. Based on the progressive graphics simplification approach, the non-feature points, feature points, feature lines and its associated bends on the contour lines are selected or deleted progressively according to the value of control variables so as to realize simplification of contour line groups with intelligence. Experimental results show that the proposed methods can effectively preserve topographic structural feature and improve the intelligence during contour line simplification.