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New Geomatics Technologies and Applications

Fig. 2. Results of the proposed model and Douglas-Poker and Viswalingam methods for Zerivar Lake

There are a number of metrics that can be used to assess the effectiveness of simplification processes. To evaluate the
efficiency of the proposed model and commonly used simplification methods, four indices of corrected middle Housdroff
distances, area differences, similarity of angle changes, and similarity of average curvature were used in this study. The corrected
Hasdroff distance index is based on the minimum distances of each point from all points of the line [25]. The minimum distance

will be zero for the Douglas Poker and Viswalingam methods because they use the initial line points for fitting, while it will not
be zero for the proposed model of this research because it does not use the points and fits them all. This index in the proposed
method was very near to zero for Zerivar Lake. The evaluation results are presented in Fig. 3. The similarity percentage of the
changes in angle and average curvature were 12 to 14% better than other methods. In terms of the area criterion, the proposed
model has maintained the area better than the feature's original form. Also, in the Douglas Poker and Viswalingam methods,
there is a significant difference between the area of the initial feature and the area of the generalized feature, which is due to
these methods' focus on preserving the feature node and causes a lot of distortion in the area. The results of evaluating the outputs

of the three methods, based on these three indicators, are shown in Figures 4 to 6 via radar chart.

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