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

   
   
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