A new two-step robust surface matching approach for three-dimensional georeferencing of historical digital elevation models

In this letter, a new approach based on a two-step (coarse and fine) automatic surface matching for registering two overlapping multidate digital elevation models (DEMs) is proposed to avoid the costly and time-consuming ground-control-point acquisition. The proposed methodology was tested to georeference a historical grid DEM obtained from a photogrammetric flight taken in 1977 and located at a heavily developed coastal area of Almera (southeast Spain). The reference DEM consisted of a newer DEM produced by the Andalusia Regional Government from a photogrammetric flight taken in 2001. The results obtained from this work may be deemed as very promising, showing high efficiency and accuracy for historical-DEM georeferencing. The vertical accuracy of the finally coregistered DEM was computed over a recent LiDAR-derived DEM (validation data set) which presented relatively unaltered areas, yielding a standard deviation that is fairly similar to the estimated uncertainty of the reference DEM.