EncDotNet.S100.Routes.Rtz

EncDotNet.S100.Routes.Rtz reads and writes RTZ route plans, the route exchange format of IEC 61174 Annex S that ECDIS and route planning tools use. It handles RTZ 1.0 (IEC 61174 Ed. 4.0:2015), 1.1 (the STM extended Annex S) and 1.2 (IEC PAS 61174-1:2021).

The package depends on EncDotNet.S100.Core and EncDotNet.S100.Navigation (for the passage plan conversion). RTZ isn't an S-100 product, so it lives beside the S-421 package rather than in it. A tool that reads both formats installs both.

Install

dotnet add package EncDotNet.S100.Routes.Rtz

Read a route

using EncDotNet.S100.Routes.Rtz;

var route = RtzReader.Read("Nab to Southampton.rtz");
Console.WriteLine($"{route.Info.RouteName} (RTZ {route.Version}), {route.Waypoints.Count} waypoints");

// A waypoint's leg is the leg directed to it, so leg i of the route is the
// leg of waypoint i + 1. GetEffectiveLeg applies the defaultWaypoint values.
for (var i = 1; i < route.Waypoints.Count; i++)
{
    var leg = route.GetEffectiveLeg(i);
    Console.WriteLine($"Leg {i}: XTD {leg?.PortsideXtd} / {leg?.StarboardXtd} NM, draught {leg?.MaxDraught} m");
}

// The calculated table wins over the manual one where both are present.
if (route.GetPlanningSchedule() is { } schedule)
    Console.WriteLine($"Departs {schedule.ElementFor(route.Waypoints[0].Id)?.Departure:u}");

To recognise a file before reading it, pass its first few kilobytes to RtzVersions.Sniff. It returns the version the file declares, or null when the file isn't RTZ.

Write a route

RtzWriter.Write(route, "Nab to Southampton.rtz", RtzVersions.V1_0);

The writer uses the target version's spelling (sheduleElement in 1.0, scheduleElement later), time format (xsd:time windows in 1.0, xsd:duration later) and extension layout.

Check a route

ToPassagePlan converts the route to the PassagePlan that the EncDotNet.S100.Navigation route and clearance checks take:

using EncDotNet.S100.Routes.Rtz;

var plan = RtzReader.Read("Nab to Southampton.rtz").ToPassagePlan();
Console.WriteLine($"{plan.Legs.Count} legs, departs {plan.Departure:u}");

It applies RTZ's semantics. Leg i reads the leg of waypoint i + 1, with the default waypoint's values filled in. Cross-track limits are converted from nautical miles to metres, and the draft is the deeper of the forward and aft draughts. Speeds and the departure come from the planning schedule; a leg without a speed gets one implied by the previous departure and its ETA. RTZ has no squat allowance.

What round-trips

The model names every attribute in the RTZ schema. Everything else is kept:

Attributes the model doesn't know, or can't parse, are kept in each element's ExtraAttributes.
The children of every extensions element are kept as XElements, with the root's namespace prefixes, so a vendor extension (such as STM's RouteInfoEx) is written back unchanged.

A route read and written in the same version keeps its content. Writing another version changes only what the versions differ in: a bare 1.0 extension element is wrapped in an extension element (manufacturer "unknown") for 1.1 and 1.2, leg extensions (a 1.2 addition) are left out of 1.0 and 1.1, and 1.2 gives every waypoint a revision.