DEM generation by contour line dilation

A method is developed to generate digital elevation models by means of the dilation of contour lines stored in a raster grid. An iterative procedure produces an extension of contour lines by applying alternative four-connected and eight-connected erosions of the background until the produced surfaces become contiguous. The limits between these surfaces correspond to a new family of intermediate contour lines that are added to the raster grid. This procedure stops when no new contour lines can be generated. C subroutines are given. The algorithm is simple to apply and has a low computational cost.