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EncDotNet.S100.Datasets.S421

Library for reading and portraying IHO S-421 (Route Plan) datasets.

S-421 defines a standard exchange format for ship route plans — waypoints, leg information, schedules, and action points — encoded as GML conforming to the S-100 framework.

Features

  • Parse S-421 GML datasets (S-100 Part 10b encoding)
  • Extract route features (Route, RouteWaypoints, RouteWaypoint, RouteSchedules, RouteSchedule, RouteWaypointLeg, RouteActionPoints, RouteActionPoint)
  • Extract information types (RouteInfo, etc.)
  • Resolve xlink:href cross-references between objects (e.g. a Route to its RouteWaypoints collection, a RouteWaypoints to its individual RouteWaypoints)
  • Convert to S-100 Part 9 FeatureXML for portrayal pipeline consumption
  • XSLT-based portrayal via the bundled S-421 Portrayal Catalogue

Overview

Key types include:

  • S421Dataset — root model containing parsed features, information types, and dataset identification. ReadMetadata() (plus static ReadMetadata(path) / ReadMetadata(stream)) is the phased-loading "peek" path (issue #460): it returns a DatasetMetadata with the declared spec and the raw WGS-84 extent folded from feature geometry (null when the dataset carries only geometry-less container features), skipping the XSLT portrayal pipeline.
  • S421Feature — a feature with type code, optional geometry, simple attributes, complex attributes, and xlink references.
  • S421InformationType — a non-spatial information type instance (e.g. RouteInfo).
  • GmlReference (namespace EncDotNet.S100.Features, in the EncDotNet.S100.Core package) — an xlink:href reference from one object to another.
  • S421ComplexAttribute — a complex attribute instance containing sub-attribute values.
  • S100GeometryType — shared enum (from EncDotNet.S100.Core) describing the geometry primitive type of a feature (None, Point, Curve, Surface).
  • S421FeatureXmlSource — IFeatureXmlSource adapter that projects an S421Dataset into S-100 Part 9 FeatureXML for XSLT portrayal rules.
  • S421PortrayalCatalogue — IVectorPortrayalCatalogue implementation that loads XSLT rules, symbols, line styles, area fills, and color palettes.

Strongly-typed data model

The types above expose the dataset as a feature bag — schema-agnostic, well suited for the portrayal pipeline, but inconvenient when client code wants to inspect routes, waypoints, or schedules directly. The EncDotNet.S100.Datasets.S421.DataModel namespace layers a strongly-typed projection on top:

  • S421RoutePlan.From(dataset, out diagnostics) — projects an S421Dataset into a typed object graph rooted at S421Route, resolving xlink:href cross-references and parsing primitive values (int, double, bool, DateTimeOffset).
  • S421Route with Info, Waypoints, Legs, ActionPoints, Schedules.
  • S421Waypoint with typed OutgoingLeg and IncomingLeg bidirectional navigation along the route.
  • S421Leg with typed StartWaypoint / EndWaypoint endpoint references, so consumers holding a leg can reach both of its bounding waypoints without coordinate matching.
  • S421ActionPoint, S421Schedule + variants (Manual / Calculated / Recommended), S421ScheduleElement.
  • Anything the typed model does not understand is preserved on each object's ExtraAttributes dictionary, so extension and future-edition attributes round-trip verbatim.
  • Projection failures (unresolved references, unparseable date/times) surface as ProjectionDiagnostic entries (from EncDotNet.S100.DataModel) rather than exceptions.

Shared abstractions. As of Pass 1 of the typed-model initiative, the projection layer consumes the cross-cutting ProjectionDiagnostic, DiagnosticSeverity, GeoPosition, XlinkResolver, AttributeParser, and ExtraAttributes helpers from EncDotNet.S100.DataModel in EncDotNet.S100.Core. The previous per-spec types (S421ProjectionDiagnostic, S421DiagnosticSeverity, S421Reference) have been removed.

Installation

dotnet add package EncDotNet.S100.Datasets.S421

Quick start

using EncDotNet.S100.Datasets.S421;

var dataset = S421Dataset.Open("RTE-TEST-GMIN.s421.gml");

Console.WriteLine($"Dataset: {dataset.DatasetIdentifier}");
Console.WriteLine($"Features: {dataset.Features.Length}");
Console.WriteLine($"Information types: {dataset.InformationTypes.Length}");

foreach (var wp in dataset.Features.Where(f => f.FeatureType == "RouteWaypoint"))
{
    var (lat, lon) = wp.Points[0];
    Console.WriteLine($"  Waypoint {wp.Attributes["routeWaypointID"]}: {lat}, {lon}");
}

Quick start (typed model)

using EncDotNet.S100.DataModel;
using EncDotNet.S100.Datasets.S421;
using EncDotNet.S100.Datasets.S421.DataModel;

var dataset = S421Dataset.Open("RTE-TEST-GMIN.s421.gml");
var plan = S421RoutePlan.From(dataset, out var diagnostics);

Console.WriteLine($"Route {plan.Route.RouteId} ed.{plan.Route.EditionNumber}");
Console.WriteLine($"  Author: {plan.Route.Info?.Author}");
Console.WriteLine($"  Vessel: {plan.Route.Info?.Vessel?.Name} (MMSI {plan.Route.Info?.Vessel?.Mmsi})");

foreach (var wp in plan.Route.Waypoints)
{
    var leg = wp.OutgoingLeg;
    Console.WriteLine(
        $"  WP{wp.WaypointNumber} {wp.Position.Latitude:F4}, {wp.Position.Longitude:F4}"
        + (leg is not null ? $" → leg {leg.Id}" : ""));
}

// Walk the route via typed endpoint references — no href parsing required.
var cursor = plan.Route.Waypoints.FirstOrDefault();
while (cursor?.OutgoingLeg is { } leg)
{
    Console.WriteLine($"  leg {leg.Id}: {leg.StartWaypoint?.Id} → {leg.EndWaypoint?.Id}");
    cursor = leg.EndWaypoint;
}

foreach (var d in diagnostics) Console.WriteLine(d);
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