Input Validation: Geographic control null handling

For the input geographic control files, if any cell is empty instead of 0, then the program will fail and throw an error “ZeroDivisionError: division by zero”.

Users would benefit from adding additional checking and converting all nulls, or “” from the input control files to 0s for numeric attributes. Or giving the user a more explicit warning message to specify that there are no valid values in the input control files.