A workflow for high-precision digital elevation model (DEM) production under complex urban environment was proposed in this paper. Firstly, outliers which were far above or below the terrain surface would be removed according to a threshold compared to surrounding points. Secondly, progressive TIN densification method was used to separate ground points from non-ground points. However, there might be some errors that manual filtering was needed to correct the misclassified points. For the area where there was absent of points, interpolation would be controlled with the help of existing survey data (break line, building boundary, etc.). Finally, all ground points were used to interpolate a 1m by 1m DEM and accuracy of the DEM was evaluated. Meanwhile, how to improve the accuracy of DEM under four typical complex situations in the urban area, i.e., overpass, complex buildings, underground park entrance, steep slope, was discussed.
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机译：提出了复杂城市环境下高精度数字高程模型（DEM）生产的工作流程。首先，与周围点相比，将根据阈值除去远高于或低于地形表面的异常值。其次，采用渐进式TIN致密化方法将地面点与非地面点分开。但是，可能存在一些错误，需要手动过滤以更正错误分类的点。对于缺少点的区域，将通过现有测量数据（折线，建筑物边界等）来控制插值。最后，使用所有接地点对1m x 1m DEM进行插值，并评估DEM的准确性。同时，讨论了如何在城市的四种典型复杂情况下，即立交桥，复杂建筑物，地下公园入口，陡坡上，提高DEM的准确性。
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