Augmenting Grid-based Contours to Improve Thin Plate DEM Generation

We present two new pre-processing techniques that improve thin plate Digital Elevation Model (DEM) approximations from grid-based contour data. One method computes gradients from an initial interpolated or approximated surface. The aspects are used to create gradient lines that are interpolated using Catmull-Rom splines. The computed elevations are added to the initial contour data set. Thin plate methods are applied to all of the data. The splines allow information to flow across contours, improving the final surface. The second method successively computes new, intermediate contours in between existing isolines, which provide additional data for subsequent thin plate processing. Both methods alleviate artifacts visible in previous thin plate methods. The surfaces are tested with published methods to show qualitative and quantitative improvements over previous methods.