The Densify process consists of several steps:
For a detailed description of the nearest neighbour method, bilinear and bicubic interpolation, refer to Resample : functionality or Resample : algorithm.
With a nearest neighbour interpolation, the pixels of the output map are assigned the same class names, IDs or values as the pixels of the input map.
A bilinear interpolation takes much less time than a bicubic interpolation.
A bilinear interpolation results in discontinuity of the first derivative. This means that a bilinear interpolation gives artefacts when you for example want to use a DFDX, DFDY, or a SHADOW filter on the map later on.
A bicubic interpolation remains continuous up to the second derivative.
See also: