windowmajority

windowmajority

Most occurring cell value within a specified square neighbourhood

Result = windowmajority(expression, windowlength)
windowlength
spatial, non spatial scalar
expression
spatial boolean, nominal, ordinal
Result
spatial type of expression

Options

--unittrue or -unitcell

--unitcell
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 most often occurring 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. At a cell, if two or more values occur the same (largest) number of times in its window, the windowlength at that cell is increased with two times the celllength of expression. The most often occurring cell value in this enlarged window is assigned to the cell under consideration. If this enlarged window still does not result in one most often occurring value, the window is progressively enlarged (with steps of two times the cellsize of expression) until a most often occuring cell value is found in the window.

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 which is not the centre cell of the window the value on expression in that cell is included in the computation of the average of the cell values in the window.

Group

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

Examples

  1. • pcrcalc
    binding
    Result2 = Result2.map;
    Expr = Expr.map;
    WinLen2 = WinLen2.map;
    initial
    report Result2 = windowmajority( Expr, WinLen2);

    • python
    Expr = readmap(“Expr.map”)
    WinLen2 = readmap(“WinLen2.map”)
    Result2 = windowmajority( Expr, WinLen2)
    Result2.map Expr.map WinLen2.map
    _images/windowmajority_Result2.png _images/windowmajority_Expr.png _images/windowaverage_WinLen2.png

  2. • pcrcalc
    binding
    Result1 = Result1.map;
    Expr = Expr.map;
    initial
    report Result1 = windowmajority( Expr, 6);

    • python
    Expr = readmap(“Expr.map”)
    Result1 = windowmajority( Expr, 6)
    Result1.map Expr.map
    _images/windowmajority_Result1.png _images/windowmajority_Expr.png

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