character. Method used for estimating the new cell values. One of:
near: nearest neighbor. This method is fast, and it can be the preferred method if the cell values represent classes. It is not a good choice for continuous values. This is used by default if the first layer of x is categorical.
bilinear: bilinear interpolation. This is the default if the first layer of x is numeric (not categorical). (3x3 cell window).
cubic: cubic interpolation. (5x5 cell window).
cubicspline: cubic B-spline interpolation. (5x5 cell window).
lanczos: Lanczos windowed sinc resampling. (7x7 cell window).
sum: the weighted sum of all non-NA contributing grid cells.
min, q1, med, q3, max, average, mode, rms: the minimum, first quartile, median, third quartile, maximum, mean, mode, or root-mean-square value of all non-NA contributing grid cells.