This tool assigns each cell in the output grid the minimum value in a moving window centred on each grid cell in the input raster (`input`). A maximum filter is the equivalent of the mathematical morphological erosion operator.

Neighbourhood size, or filter size, is specified in the x and y dimensions using the `filterx` and `filtery` flags. These dimensions should be odd, positive integer values, e.g. 3, 5, 7, 9... If the kernel filter size is the same in the x and y dimensions, the silent `filter` flag may be used instead (command-line interface only).

This tool takes advantage of the redundancy between overlapping, neighbouring filters to enhance computationally efficiency. Like most of WhiteboxTools' filters, it is also parallelized for further efficiency.

## See Also

maximum_filter

## Function Signature

`def minimum_filter(self, raster: Raster, filter_size_x: int = 11, filter_size_y: int = 11) -> Raster: ...`

## Project Links

WbW Homepage User Manual Support WbW