Understanding logical values
Logical values simply keep
track of the values, true and false. In Map Algebra, any non-zero input value
is considered to be a logical true, and zero is considered a logical false.
Some Map Algebra operators and functions evaluate input cell values and return
logical 1 values (true) and logical 0 values (false). The relational and
Boolean operators all return logical values.
In this example, cells
are evaluated as to whether their value is greater than 15. The value 1, or
logical true, is assigned to those cells that are greater than 15. The value 0,
or logical false, is assigned to all other cells.