Why do COSTALLOCATION, COSTDISTANCE and COSTBACKLINK fail when using floating point grid as the source grid?

Description

If a floating point grid is used as the <source_grid> for COSTALLOCATION, COSTDISTANCE and COSTBACKLINK, an error message similar to the following will appear:

"Grid: costalloc = COSTALLOCATION(srcgrd_flt, costgrd)
Source_grid SRCGRD must be of integer type to be used for allocation values.
Cost Distance mapping Failed
AML MESSAGE - Stopping execution of AML file due to ERROR condition"

The Workstation documentation indicates that the <source_grid> can be integer or floating point for COSTALLOCATION, COSTDISTANCE and COSTBACKLINK. This is not correct.

Floating point grids are not supported as input for the source grid.

Workaround