clump
clump
Contiguous groups of cells with the same value (‘clumps’)
Result = clump(expression)
 expression
 spatial
boolean, nominal, ordinal
 Result
 spatial
nominal
Options
diagonal or nondiagonal
 diagonal
 cells of the same value are grouped if they are within the immediate 8cell neighbourhoodnof each other. This includes if they are to the right or left, above or below,nor are diagonal to each other (eight nearest neighbours, default).
 nondiagonal
 cells of the same value are grouped only if the cells are directly to the rightnor left, or above or below each other (four nearest neighbours).
Operation
Cells that have the same value on expression and are neighbours are grouped. Every group of cells satisfying these conditions is assigned a unique value on Result. Cells without neighbours with the same value on expression are also assigned a unique value on Result. The kind of connectivity needed for cells to be neighbours is specified by the option.
Notes
Cells with a missing value on expression are assigned a missing value on Result.
Group
This operation belongs to the group of Area operators
Examples
• pcrcalc
binding
Result1 = Result1.map;
Expr = Expr.map;
initial
report Result1 = clump( Expr);
• python
Expr = readmap(“Expr.map”)
Result1 = clump( Expr)
Result1.map 
Expr.map 


• pcrcalc
#! –nondiagonal
binding
Result2 = Result2.map;
Expr = Expr.map;
initial
report Result2 = clump( Expr);
• python
setglobaloption(“nondiagonal”)
Expr = readmap(“Expr.map”)
Result2 = clump( Expr)
Result2.map 
Expr.map 

