摘要
Li-Openshaw算法是一种基于客观综合自然规律的自适应线状要素综合算法,使用该算法可得到较合理真实的综合结果。在分析Li-Openshaw算法特点的基础上,依据线化简的原则和目的,对算法进行改进:①首先提出利用点与直线的关系来识别弯曲以找出所有局部极大值点的方法以保持曲线整体形状;②SVO圆形与待综合曲线发生多次相交时按照线的顺序索引找到第一个近似交点,选取与曲线上圆心与交点的中点最接近的原始数据点作为综合后的选取点。在此基础上,给出化简时间、位移标准差和位置误差等评价指标,提出基于分形理论的曲线形状结构特征的评估方法等对两种算法进行比较与评估,实验结果证明,同原算法相比,改进的Li-Openshaw算法在线化简中更好地保持曲线的整体形状,具有较高的位置精度,提高化简效率。
Li-Openshaw algorithm is a self-adapted linear feature＇s generalization algorithm based on impersonality generalized natural law, and using this algorithm can get reasonable and genuine generalization results. On the basis of analyzing characteristics of Li-Openshaw algorithm, according to the principle and purpose of linear simplification, Li-Openshaw algorithm is improved as follow： （1） first method of identifying the bend using the relationship between point and line is proposed, in order to find all the local maximum points and save to keep the entire shape of curve before simplification; （2） find the first approximate point of intersection according to lines＇ index when there are more than one point of intersection between SVO circularity and curve, then select the point which is nearest to the midpoint of center point of a circle and point of intersection on the curve to save after generalization. What＇s more, two algorithms are compared and assessed by evaluating figures such as time to simplification, Standardized Measure of Displacement, position error and so on, and the method of curves＇ shape structure characteristic assessment based on fractal theory is proposed. According to experiments＇ results, compared with original algorithm, improved algorithm can keep the entire shape of curve better, has a higher position accuracy and increases simplifying speed.
出处
《测绘学报》
EI
CSCD
北大核心
2007年第4期450-456,共7页
Acta Geodaetica et Cartographica Sinica
基金
国家自然科学基金项目(40701157)
国家863计划项目(2007AA12Z211)
