windowminimum

windowminimum

Minimum value within a specified square neighbourhood

Result = windowminimum(expression, windowlength)
expression
spatial ordinal, scalar
windowlength
spatial, non spatial scalar
Result
spatial expression

Options

--unittrue or --unitcell

--unittrue
windowlength is measured in true length (default)
--unitcell
windowlength is measured in number of cell lengths

Operation

For each cell a square window with the cell in its centre is defined by windowlength. The windowlength is the length of the window in horizontal and vertical directions. For each cell on expression, the minimum cell value within its window is determined and assigned to the corresponding cell on Result. Both cells on expression which are entirely in the window and cells which are partly in the window are considered.

Notes

The cell value on windowlength should be greater than 0, else a missing value is assigned to the corresponding cell on Result.

A cell on windowlength with a missing value results in a missing value on Result at the corresponding cell. However, if a missing value on windowlength occurs in a cell in the window which is not the centre cell of the window the value on expression in that cell is considered for determination of the minimum cell value in the window.

Group

This operation belongs to the group of Neigbourhood operators; window operators

Examples

  1. • pcrcalc
    binding
    Result1 = Result1.map;
    Expr = Expr.map;
    initial
    report Result1 = windowminimum( Expr, 6);

    • python
    Expr = readmap(“Expr.map”)
    Result1 = windowminimum( Expr, 6)
    Result1.map Expr.map
    _images/windowminimum_Result1.png _images/windowaverage_Expr.png

  2. • pcrcalc
    binding
    Result2 = Result2.map;
    Expr = Expr.map;
    WinLen2 = WinLen2.map;
    initial
    report Result2 = windowminimum(Expr, WinLen2);

    • python
    Expr = readmap(“Expr.map”)
    WinLen2 = readmap(“WinLen2.map”)
    Result2 = windowminimum(Expr, WinLen2)
    Result2.map Expr.map WinLen2.map
    _images/windowminimum_Result2.png _images/windowaverage_Expr.png _images/windowaverage_WinLen2.png

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