focal_minimum

focal_minimum#

Signature#

focal_minimum(array, kernel) → Field#

Determine the minimum value in a neighbourhood

Parameters:

  • array (Field) – Arithmetic array to analyse

  • kernel (Kernel) – Neighbourhood to search. The weights must be integral and will be used to determine whether a cell’s value is to be evaluated (weight is non-zero) or not (weight is zero).

Returns:

New arithmetic array

Description#

Focal operation for determining the minimum value in a neighbourhood.

No-data handling#

As long as there is at least one valid value found within the input neighbourhood, a valid value is written to the focal cell in the output array. Only when no such value is found is a no-data value written. The output array is likely to contain less no-data values than the input array.

Example#

/* TODO */

auto const kernel = lue::box_kernel<BooleanElement, rank>(1, 1);
auto const result = lue::value_policies::focal_minimum(array, kernel);

// TODO

kernel = np.full((3, 3), 1, dtype=lfr.boolean_element_type)
result = lfr.focal_minimum(array, kernel)
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