EncDotNet.S100.Datasets.S201 0.25.1

EncDotNet.S100.Datasets.S201

EncDotNet.S100.Datasets.S201 reads IALA S-201 Aids to Navigation Information datasets: GML files (S-100 Part 10b, S-100 GML 5.0 profile) that authorities use to exchange detailed data about their aids to navigation. It parses a dataset, resolves the links between aids, equipment and information records, projects it into a typed inventory, validates it, and loads the S-201 portrayal catalogue. Reference it when you need typed access to S-201 data or its validation rules. To open and render any product, including S-201, use the EncDotNet.S100 package, which includes this one.

Install

dotnet add package EncDotNet.S100.Datasets.S201

Read a dataset

Open the dataset, then project it into the typed inventory:

using EncDotNet.S100.Datasets.S201;
using EncDotNet.S100.Datasets.S201.DataModel;

var dataset = S201Dataset.Open("path/to/aton.gml");
var inventory = S201AtonInventory.From(dataset, out var diagnostics);

// List each structure and the equipment mounted on it.
foreach (var structure in inventory.Structures)
{
    Console.WriteLine($"{structure.FeatureClass} {structure.AtoNNumber}");
    foreach (var equipment in structure.MountedEquipment)
    {
        var kind = equipment is S201Light light
            ? $"Light/{light.Kind}"
            : equipment.FeatureClass;
        Console.WriteLine($"  {kind} {equipment.Id}");
    }
}

// Filter AIS aids by kind.
foreach (var ais in inventory.ElectronicAtoNs.Where(a => a.Kind == AisAtonKind.Virtual))
    Console.WriteLine($"Virtual AIS {ais.Id} MMSI={ais.MmsiCode}");

foreach (var diagnostic in diagnostics)
    Console.Error.WriteLine($"{diagnostic.Severity} {diagnostic.Code}: {diagnostic.Message}");

Main types

• S201Dataset: the parsed dataset, with its features, information types and dataset identification. Open takes a path or a stream. ResolveReferencedFeatures and ResolveReferencedInformationTypes follow a feature's xlinks by role name. ReadMetadata (static, for a path or stream, or on an open dataset) returns the declared product specification and the WGS 84 extent of the feature geometry without running portrayal. The extent is null when no feature has geometry.
• S201Feature: a feature with its type code, geometry, simple and complex attributes, information references and feature references. It implements IS100Feature.
• S201InformationType: an information type, such as AtonStatusInformation, PositioningInformation, AtoNFixingMethod or SpatialQuality. It implements IS100InformationType.
• S201InformationReference: a link from a feature to an information type, read from an xlink:href attribute.
• S201FeatureReference: a link from a feature to another feature, such as equipment to its host structure, read from an xlink:href attribute.
• S201ComplexAttribute: a complex attribute's sub-attributes. It implements IS100ComplexAttribute.
• S201AtonInventory: the typed model. See Typed data model.
• S201AtonRules: the validation rule set. See Validate.
• S201FeatureXmlSource: an IFeatureXmlSource that converts an S201Dataset to the S-100 Part 9 FeatureXML form (Dataset/Features/* and Dataset/InformationTypes/*) that the S-201 XSLT rules match against.
• S201PortrayalCatalogue: an IVectorPortrayalCatalogue that loads the bundled catalogue's XSLT rules, symbols, line styles, area fills and colour palettes.

The reader recognizes features by namespace, so it doesn't need a list of the 62 concrete S-201 feature types. It splits xlinks into two kinds:

• Information references, whose target is an information type. For example, AtoNStatus to AtonStatusInformation, and Positioning to PositioningInformation.
• Feature references, whose target is another feature. For example, theParentFeature and theSubordinateFeature from the Structure/Equipment aggregation, and peer from Aggregations and Associations.

S-201 and S-125

S-201 is the IALA product specification for exchanging aid-to-navigation data between authorities. It carries the full model that IALA member authorities use: operational and technical attributes, equipment lifecycle, AIS aid routing and more. It isn't meant for ECDIS display.

EncDotNet.S100.Datasets.S125 covers many of the same physical objects (lights, buoys, beacons, AIS aids), but S-125 is the IHO's smaller aid-to-navigation feature set for ECDIS. The two are separate standards, with separate feature catalogues, XSDs and portrayal catalogues, and different audiences.

This library treats S-125 and S-201 as independent products. When an S-125 and an S-201 dataset cover the same area, the viewer draws them as separate layers; it doesn't merge or deduplicate them.

Typed data model

S201Dataset is a feature bag: attributes are ImmutableDictionary<string, string> values, xlinks are unresolved strings, and you'd have to follow equipment-to-structure links yourself. The EncDotNet.S100.Datasets.S201.DataModel namespace projects it into typed objects:

• S201AtonInventory is the root. It has typed lists (Structures, Equipment, ElectronicAtoNs) and the resolved Aggregations, Associations, StatusInformation, PositioningInformation, FixingMethods and SpatialQualities.
• S201AtonObject is the abstract base for every aid. It has the attributes all aids share: identifier, lifecycle dates (InstallationDate, FixedDateRange, PeriodicDateRange), inspection data, source, status history, and geometry as an S201GeometryKind plus an ImmutableArray<GeoPosition>.
• S201StructureObject is for beacons, buoys, landmarks, lighthouses, light vessels, offshore platforms and other structures. It adds AtoNNumber, AidAvailabilityCategory, Condition, ContactAddress, the resolved MountedEquipment, and typed PositioningInformation and FixingMethods.
• S201Equipment is for daymarks, fog signals, radar reflectors, racons, power sources and other equipment. HostStructure is the structure it's mounted on.
• S201Light is an S201Equipment that covers the four light types in the feature catalogue (LightSectored, LightAllAround, LightAirObstruction, LightFogDetector); Kind (a LightKind) says which. It adds Height, Status codes, VerticalDatum, VerticalLength, EffectiveIntensity and PeakIntensity.
• S201ElectronicAtoN covers the three AIS aid types (VirtualAISAidToNavigation, PhysicalAISAidToNavigation, SyntheticAISAidToNavigation); Kind (an AisAtonKind) says which. It has MmsiCode, the AIS Status and, for physical and synthetic aids, the resolved HostStructure.
• S201GenericAtonObject is for aid features with no dedicated class, such as NavigationLine, DataCoverage and DangerousFeature. It has the shared S201AtonObject attributes and geometry, and keeps everything else in ExtraAttributes.

The projection is read-only. From throws only when the dataset has no features and no information types. Everything else, such as an unresolved xlink, an attribute that doesn't parse or a target of an unexpected type, becomes a ProjectionDiagnostic in the out parameter.

Compared with the S-125 typed model

The S-201 typed model adds what the authority exchange needs:

1. Equipment and host structure linked both ways (Equipment.HostStructure, Structure.MountedEquipment).
2. Lifecycle dates (InstallationDate, FixedDateRange, PeriodicDateRange) on every aid.
3. Status history through the AtoNStatus information binding, including the ChangeTypes code list.
4. Positioning and fixing-method bindings on structures.
5. Remote monitoring system data on equipment.

The two typed models share only the types in the EncDotNet.S100.DataModel namespace (GeoPosition, ProjectionDiagnostic, ProjectionContext, XlinkResolver, AttributeParser, ExtraAttributes), not any product-specific types. If you use both, project each dataset to its own model and reconcile them in your code.

Validate

S201AtonRules, in the EncDotNet.S100.Datasets.S201.Validation namespace, is the default rule set for S201AtonInventory. Rule IDs have the form S201-R-{clause} and trace to S-201 Edition 2.0.0, or to S-100 Part 10b §6.2 and §6.4 for coordinates and identifiers. The rules focus on the integrity of the inventory: xlink resolution, equipment-to-structure links, aggregation membership and AIS MMSI format. The EncDotNet.S100 package's dataset.Validate() runs the same rule set.

using EncDotNet.S100.Datasets.S201;
using EncDotNet.S100.Datasets.S201.DataModel;
using EncDotNet.S100.Datasets.S201.Validation;

var dataset = S201Dataset.Open("path/to/aton.gml");
var inventory = S201AtonInventory.From(dataset, out _);
var report = S201AtonRules.Validate(inventory);

foreach (var finding in report.Findings)
    Console.WriteLine($"[{finding.Severity}] {finding.RuleId}: {finding.Message}");

The rules check one dataset at a time. Cross-dataset checks, such as comparing an aid's position with an S-101 chart, aren't included. Problems found while projecting are reported in the diagnostics from From.

Portrayal

The bundled S-201 portrayal catalogue's top-level template is main_PaperChart.xsl. It's taken from the IALA-IGO upstream repository at commit 7ddfe8145812141fb8ca413107254f42febd893e, and has a single Day colour profile. See EncDotNet.S100.Specifications/content/S201/README.md for its provenance and how upstream files were renamed.

Encoding notes

• S-201 datasets come in two shapes, and the reader accepts both:
  • The shape the bundled application schema declares: a <Dataset> root in the namespace http://www.iho.int/S-201/gml/cs0/1.0, with <member> wrappers for features and <imember> wrappers for information types, as in S-125 and S-127. The hyphen and /gml/cs0/1.0 suffix are part of the namespace.
  • The shape seen in IALA-IGO sample and operational datasets: a <DataSet> root in the namespace http://www.iho.int/S-201/gml/cs0/2.0 (or the older http://www.iho.int/201/gml/1.0), with one <members> container for features and information types. Features in this shape are usually in the default namespace.
• Geometry uses the S-100 GML 5.0 profile namespace, http://www.iho.int/s100gml/5.0. The reader also accepts the older S-100 GML 1.0 namespaces that some encoders still write.
• Coordinates in <gml:pos> and <gml:posList> are latitude then longitude for EPSG:4326 (S-100 Part 10b §6.2).
• Some features have no geometry: abstract supertypes such as AidsToNavigation, StructureObject and Equipment, and aggregation containers such as AtonAggregation and AtonAssociation. Code that reads features must allow for that.
• Time validity (fixedDateRange, periodicDateRange) is UTC. Don't convert it to local time when you read it.

License

The bundled S-201 specification assets in EncDotNet.S100.Specifications are © IALA and are used under their open-publication terms; see https://github.com/IALA-IGO/S-201_AtoN-Information.

See also

• Loading datasets: open files, folders, ZIPs and exchange sets through the EncDotNet.S100 package.
• Reading product data: features, information types and typed models for each product.
• Typed data models: the typed root for each product and the shared diagnostic codes.
• Custom catalogues and validation: run the bundled rules and add your own.