By default the web service does not allow routing through the following:-

The Kiel and Corinth canals, the Magellan, Bonifacio, Messina straits, the Bahama channel, West of Taiwan and Laeso Island, Chelyuskina, inshore at North Cape, and the Norwegian inshore and Indreleia routing.  All other passages, capes and canals are open and used.

When the GetShortestDistance method does not obtain the route that you require we provide two methods of obtaining the 'correct' distance, 'going via' and 'user defined routing' These two methods are explained below.

Going 'via'

This is the simplest method and, for the majority of cases, will provide the route you require without using the more complex method of user defined routing.

There are 21 via codes available, these are tabulated below and are also obtainable via the GetViaCodes method.

The via method 'hides' away the complexity of manipulating routing points and is often the simplest, quickest and most effective method of obtaining the majority of distances and routes.

User defined routing

Where routing 'via' does not get you the route you require, you can define your own routing restrictions and obtain the distance using GetDistanceUsingRouting method.

The 'engine' that powers the web service is very efficient at seeking out the shortest route and needs to be constrained by closing off canals, capes, straits and other passages in order to force it into going the way you want.

When specifying route options, you do so via a code string, the default routing string is shown below.

014ENVGOCASLPANSUZDOVHINLOMSINSUNCHOCGHNCATHUSP1600SP0400SP0410SP5110SP5100SP5120RP4700RP4710RP9995RP9993RP9998SP0700

The code string can be broken into two distinct parts, Primary and Advanced routing, this is analogous with the methods used to display routing options in a number of our commercial products.

Primary routing options are the first part of the string and consist of 3 digits (representing the number of primary codes that follow) and then a number of 3 character codes, there are no spaces between these codes nor the number at the start of the string, thus

014ENVGOCASLPANSUZDOVHINLOMSINSUNCHOCGHNCATHU

translates to 14 primary codes which are ENV, GOC, ASL, PAN, SUZ, DOV, HIN, LOM, SIN, SUN, CHO, CGH, NCA and THU

The three character codes indicate to the engine that the Routing option is IN USE or OPEN, the absence of a code indicates that the routing option is NOT in use or is CLOSED. Experience has shown that these Primary codes provide sufficient routing control for the majority of routes obtained from the tables.

The following table shows the complete list of codes that are available in the current release of the tables, you can sort this table by clicking on the column header.

 

 

The remainder of the routing string consists of groups of 6 character codes that represent Advanced routing points, unlike Primary codes the presence of a code in this section of the string indicates to the service that this routing point should be CLOSED. The Advanced routing codes are provided to allow absolute control over routing when abnormal conditions apply or specific routing is required. Routing through Korsor (the Great Belt) rather than the Sound or avoiding routing via the Bangka passage are examples.

The default Advanced codes are show below and expanded into a table for clarity.

SP1600SP0400SP0410SP5110SP5100SP5120RP4700RP4710RP9995RP9993RP9998SP0700

 

This single 'routing string' is capable of controlling all routing in the web service.

You may have noticed that by default a number of Advanced codes are missing from the default routing string, these are:-

KIE, COR, MAG, BON, MES, BAH, WOT, NCI, CHL, NIR, N10, CCN, CCS, CDE and CDW - All these Primary routing points are closed by default as are Advanced routing points SP1600, SP0400, SP0410, SP5110, SP5100, SP5120, RP4700, RP4710, RP9995, RP9993, RP9998 and SP0700.

There is a relationship between certain Primary and Advanced routing points. A method called GetRoutingPointXml has been provided that returns XML that contains the full list of Primary and Advanced routing points and their relationships where it exists. This XML is used in the demonstration program to load a property inspector, you should study the demo source to familiarise yourself with setting Primary routing points and ensuring that Advanced routing points 'follow'.

 

Example North Cape Inshore

Routing through North Cape Inshore TSS's (Traffic Separation Schemes) is controlled by the Primary code of NCI. There are however two Advanced routing points for North Cape Inshore, North Cape - Inshore - East Bound and North Cape - Inshore - West Bound. When the Primary North Cape Inshore routing point is closed, these two will be closed automatically and should NOT BE opened unless the Primary routing point is also Open. In the demo project the object inspector for Routing points will disable the two advanced routing points whilst the Primary routing point is closed and enable them when it is open, see the display of Advanced routing below (note that Chelyuskina is also disabled as the Primary is also closed):

 

The table below shows which Primary routing points are 'controllers' and which Advanced routing points they control:

You are urged to look at the Demo program for the web service which includes the source code. This will give you a valuable insight into the way that user defined routing is designed to work.