The authors would like to clarify that in the published article [1], the proposed classification method is an improvement of their previous method of multi-resolution hierarchical classification (MHC) which used computationally costly analytical thin plate spline (TPS) for interpolating initial ground points [2]. The improved classification method [1] replaced the interpolated values with the original values, and used discrete cosine transform (DCT)-based finite difference TPS, as previously developed by Damien Garcia in [3], to perform interpolations only where no lidar points were located. The PLOS ONE article does not present a new interpolation method; basic information about the existing interpolation methods of analytical TPS and (weighted) finite difference TPS was included in the article for completeness.
展开▼
