gis:sampling-method-of

gis:sampling-method-of RasterDataset

Reports the sampling method used to compute the value of the given raster dataset at a single point, or over an area smaller than a single raster cell. Sampling is performed by the GIS extension primitives raster-sample, resample, convolve, and apply-raster. The sampling method will be one of the following:

• "NEAREST_NEIGHBOR": the value of the cell nearest the sampling location is used.
• "BILINEAR": the value of the four nearest cells are sampled by linear weighting, according to their proximity to the sampling site.
• "BICUBIC": the value of the sixteen nearest cells are sampled, and their values are combined by weight according to a piecewise cubic polynomial recommended by Rifman (see Digital Image Warping, George Wolberg, 1990, pp 129-131, IEEE Computer Society Press).
• "BICUBIC_2": the value is sampled using the same procedure and the same polynomial as with BICUBIC above, but using a different coefficient. This method may produce somewhat sharper results than BICUBIC, but that result is data dependent.

For more information on these sampling methods and on raster sampling in general, see this wikipedia article.