| Parameters | AtoBviaCToken | String | 
| FromPortCode | String | |
| String | ||
| ToPortCode | String | |
| Long | ||
| MapDetails | ||
| Return Value | 
This service call is used to obtain the shortest distance between two ports routing through a via point, the permitted via points are tabulated here.
If the Distance returned is negative then this value is the error code, these are tabulated here.
This method requires a 'token' from logging into the service.