This filter is a modification of the wbw_mean_filter, whereby the highest and lowest values in the kernel are dropped, and the remaining values are averaged to replace the central pixel. The result is a low-pass smoothing filter that is more robust than the wbw_mean_filter, which is more strongly impacted by the presence of outlier values. It is named after a system of scoring Olympic events.
Arguments
- x
Raster object of class WhiteboxRaster. See
wbw_read_raster()
for more details.- filter_size_x
integer
, X dimension of the neighbourhood size- filter_size_y
integer
, Y dimension of the neighbourhood size
Value
WhiteboxRaster object containing filtered values
Details
Neighbourhood size, or filter size, is specified in the x and y dimensions
using filter_size_x
and filter_size_y
These dimensions should
be odd, positive integer values (e.g. 3L, 5L, 7L, 9L, etc.).
References
For more information, see https://www.whiteboxgeo.com/manual/wbw-user-manual/book/tool_help.html#olympic_filter
Examples
f <- system.file("extdata/dem.tif", package = "wbw")
wbw_read_raster(f) |>
wbw_olympic_filter(filter_size_x = 3L, filter_size_y = 3L)
#> +-----------------------------------------------+
#> | WhiteboxRaster |
#> | dem.tif |
#> |...............................................|
#> | bands : 1 |
#> | dimensions : 726, 800 (nrow, ncol) |
#> | resolution : 5.002392, 5.000243 (x, y) |
#> | EPSG : 2193 (Linear_Meter) |
#> | extent : 1925449 1929446 5582091 5585717 |
#> | min value : 64.262451 |
#> | max value : 359.870361 |
#> +-----------------------------------------------+