Then triangulation is used for the calculation of a polygon's surface area, and viewshed analysis is carried out using the method of reference plane.

设计方案中对已有的数字高程模型进行加密内插，使用三角化方法来计算地表曲面面积，采用参考平面法实现区域通视分析。

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For viewshed analysis based on DEM database, the algorithm having a good experimental effect reduces obviously the frequency of access to database with lower time complexity.

对基于DEM数据库的可视域分析，该算法在时间复杂度较低的情况下大大减少了访问数据库的次数，取得了很好的效果。

youdao

For viewshed analysis based on DEM database, the algorithm having a good experimental effect reduces obviously the frequency of access to database with lower time complexity.

对基于DEM数据库的可视域分析，该算法在时间复杂度较低的情况下大大减少了访问数据库的次数，取得了很好的效果。

youdao