Routing Via

By default the Distance Tables will provide the shortest route between two locations, taking into account the environmental risk associated with the route; but on many occasions an alternative route will be required. This can be achieved by adjusting the Routing Options that will be used when calculating a distance. For example, if the shortest route between two ports involves transiting the Suez Canal, then 'closing' the Suez Canal routing point will result in the Distance Tables finding the next shortest route by going a different way.

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Shortest Routing

As an example, consider a voyage between Copenhagen and Chiba.

Using the system default routing options, the distance is 12,405 Nm routing via the Suez Canal.

Via Panama

By closing the Suez Canal routing point, a distance of 12,927 Nm is obtained for a route via the Panama Canal.

Via Cape of Good Hope

Then by closing the Panama Canal, a distance of 15,370 Nm is obtained for a route via the Cape of Good Hope.

Distances quoted are from version 1.1.3.97 of the Distance Tables dated 4th May 2012. Similar distances obtained from other versions of the Distance Tables may be different if adjustment to the routes used become necessary as a result of changes to regulatory/recommended routing or changes identified with reference to the UKHO Notices to Mariners.

Via Cape of Good Hope

The same route and distance can also be achieved by specifying the Cape of Good Hope in the ports list.

In this example, the Cape of Good Hope is a single location and deserves no further consideration when used as a via point. Since the Distance Tables reflect the use of Traffic Separation Schemes further consideration has to be give to the via point where the location to be used can differ depending on the direction of travel. Fortunately, the issue is addressed within the software by use of the concept of 'Assisted Routing', which has its own help topic.