A multi-scale representation method for map curves based on BLG tree structure

Abstract

Based on the linear BLG tree storage structure, a new multi-scale representation method for map curves is proposed. Firstly, the feature point sets under different thresholds are calculated by DP algorithm, after which data points are stored in a certain order by using the linear BLG storage structure, the map scales corresponding to different feature point sets are calculated according to the minimum visible distance of human eyes and combined with the average distance between adjacent feature points, finally, according to the preset map scale, the corresponding feature point sets are selected, the B spline curve is used to generate the final map curve by fitting. The experimental results show that, unlike the frequency filtering method which shifts the local features of the simplified curves, this method can take into account the overall shape of the simplified curves and the accuracy of the local features, and the multi-scale expression results with obvious differences can be formed by choosing different scales, which verifies that this method has better effects on the multi-scale expression of map elements.