To determine the nearest neighbor, the algorithm uses the inverse of the transformation matrix to calculate the image file coordinates of the desired geographic coordinate. The pixel value occupying the closest image file coordinate to the estimated coordinate will be used for the output pixel value in the georeferenced image.
Output values are the original input values.
Other methods of resampling tend to average surrounding values. This may be an important consideration when discriminating between vegetation types or locating boundaries. Since original data are retained, this method is recommended before classification. Easy to compute and therefore fastest to use. The image has a rough appearance relative to the original unrectified data.