Table of Contents

EncDotNet.S100.Datasets.S411

Library for reading and portraying IHO/JCOMM S-411 (Ice Information for Surface Navigation) datasets.

S-411 provides a standard data model for distributing sea-ice and lake-ice information as GML-encoded datasets conforming to the S-100 framework.

Features

  • Parse S-411 GML datasets (S-100 Part 10b encoding, both s100gml/1.0 and s100gml/5.0 profile namespaces)
  • Extract sea-ice features (SeaIce, LakeIce, Iceberg, IceEdge, IceLead, etc. — see the S-411 1.2.1 Feature Catalogue for the full set)
  • Convert to S-100 Part 9 FeatureXML for portrayal pipeline consumption
  • XSLT-based portrayal via the S-411 Portrayal Catalogue

Overview

Key types:

  • S411Dataset — root model containing parsed features 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.
  • S411Feature — a geographic feature with type code, geometry, simple attributes, and complex attributes.
  • S411ComplexAttribute — a complex attribute instance containing sub-attribute values.
  • S100GeometryType — shared enum (from EncDotNet.S100.Core) describing the geometry primitive type of a feature.
  • S411FeatureXmlSource — IFeatureXmlSource adapter that projects an S411Dataset into S-100 Part 9 FeatureXML for XSLT portrayal rules.
  • Feature geometry reaches the renderers through the shared FeatureGeometryProvider<TFeature> (IFeatureGeometryProvider, from EncDotNet.S100.Core), which the dataset processor builds over the parsed features.
  • S411PortrayalCatalogue — IVectorPortrayalCatalogue implementation that loads XSLT rules, symbols, line styles, area fills, and color palettes.

Typed data model

In addition to the raw S411Dataset / S411Feature shapes used by the portrayal pipeline, the library exposes a strongly-typed projection under EncDotNet.S100.Datasets.S411.DataModel built on the shared EncDotNet.S100.DataModel abstractions in EncDotNet.S100.Core. This mirrors the typed projections added for S-124, S-125, S-128, and S-201 (see PRs #69, #70, #71, and #72).

Key types:

  • S411SeaIceInventory — top-level projection with a static From(S411Dataset, out IReadOnlyList<ProjectionDiagnostic>) factory that walks the source feature bag and produces typed subclasses.
  • S411IceFeature — abstract base. Concrete subclasses: S411SeaIce, S411LakeIce, S411Iceberg, S411IceEdge, S411IceLead, S411IceThickness, S411SnowCover, S411StageOfMelt, S411DataCoverage, and S411OtherFeature (catch-all).
  • S411EggCode — typed bundle for the WMO egg-code attributes carried by SeaIce / LakeIce features. Both vocabularies (JCOMM iceact/iceapc/icesod/iceflz and the IHO 1.2.1 sample totalConcentration/snowDepth) feed the same shape. List-valued JCOMM attributes are preserved as raw text because real-world producers serialise them as Python-list-style strings rather than the standard WMO tokenisation.
  • S411GeometryKind — None / Point / Curve / Surface.

Feature-type normalisation maps the JCOMM lowercase short codes (seaice, lacice, icebrg, icelne, icethk, snwcvr, stgmlt, …) to the canonical PascalCase Feature Catalogue class names. Both GML shapes therefore land on the same typed subclass, and consumers can dispatch on NormalizedFeatureType without caring which shape the dataset was emitted in. The raw element name remains available on SourceFeatureType.

S-411 carries no information types and no xlink cross-references, so the projection does not need an XlinkResolver graph; it still threads a ProjectionContext so attribute-parse failures surface as ProjectionDiagnostic entries rather than exceptions. The projection only throws when the source dataset has no features at all.

Example:

using var s = File.OpenRead("ice.gml");
var dataset = S411Dataset.Open(s);
var inventory = S411SeaIceInventory.From(dataset, out var diagnostics);

foreach (var seaIce in inventory.IceFeatures.OfType<S411SeaIce>())
{
    var conc = seaIce.EggCode?.TotalConcentration;
    // ... dispatch on seaIce.NormalizedFeatureType / seaIce.GeometryKind
}

Notes

Two GML shapes in the wild

S-411 1.2.1 datasets are encountered in two distinctly different XML shapes, both of which this reader handles:

  1. JCOMM / Canadian-Ice-Service operational shape (the common case in real-world data). Root element is <ice:IceDataSet xmlns:ice="http://www.jcomm.info/ice">, members are wrapped one-per-<ice:IceFeatureMember>, and feature elements use the short lowercase codes (ice:seaice, ice:icebrg, ice:lacice, ice:icelne, …). Geometry is inline as a direct <gml:Polygon> / <gml:LineString> / <gml:Point> child. The bundled portrayal catalogue was authored against this shape.

  2. IHO 1.2.1 sample shape (transitional; only seen in the official IHO S-411-Product-Specification repository's samples/ folder). Root is a bare <Dataset> with a plural <members> wrapper holding many feature siblings, and feature class names are PascalCase (SeaIce, Iceberg, …). The dataset-identification block declares the spec via <S100:productIdentifier>S-411</S100:productIdentifier>.

The reader dispatches on the root element and produces an S411Dataset from either. The original parsed XDocument is preserved on S411Dataset.SourceDocument and passed through unchanged to the XSLT portrayal pipeline so that the official catalogue's element names and namespaces are honoured exactly.

Portrayal catalogue

The bundled pc/ tree under EncDotNet.S100.Specifications is byte-identical to the upstream catalogue at iho-ohi/S-411-Product-Specification (version 1.2.1). No edits, additions, or <ruleFile> insertions are made.

The upstream mainRule (pc/Rules/main.xsl) emits a display-list dialect that is incompatible with this codebase's Part9DisplayListReader (it uses <symbol><symbolReference>X</symbolReference></symbol> instead of <symbol reference="X"/>, etc.). To preserve the catalogue intact while still rendering, this library ships an embedded adapter at Adapter/main.xsl. S411PortrayalCatalogue.GetCompiledRuleAsync("mainRule") substitutes the adapter for the catalogue's mainRule only; all other rule references (sub-templates, simple-symbol templates, etc.) are loaded from the unmodified PC. The adapter handles both GML shapes described above.

Selectable display modes (issue #416)

A single S-411 dataset carries the full WMO egg code per polygon (iceact, iceapc, icesod, iceflz), and the upstream PC declares three display modes (S-100 Part 9 §11.7). The adapter honours the active mode via an <xsl:param name="displayMode"/> threaded in by the vector engine from the catalogue's DisplayModeController:

Display-mode id CLI --display-mode token Fill
IceScientificIceactDisplayMode (default) ice-concentration Total concentration — WMO iceact colours
IceScientificIcesodDisplayMode ice-sod Stage of development — WMO icesod colours
IceNavigationalDisplayMode ice-navigational Provisional preview derived from total concentration (adapter-authored) — not a POLARIS/RIO navigational-risk computation

The concentration and stage-of-development colours are held inline in the adapter as pre-converted #RRGGBB literals, mirrored from the bundled upstream tables (pc/Rules/seaice_wmo_iceact.xsl / seaice_wmo_icesod.xsl). Those upstream files remain the canonical source of the values and stay byte-identical to upstream; the S411WmoColourParityTests xunit test parses them, converts each number($iceX)=N -> colorToken "R G B" entry to #RRGGBB, and asserts equality with the adapter's inline tables — so any upstream drift fails the build loudly rather than silently degrading at render time. This keeps the single-source guarantee without runtime document() plumbing or per-render parse cost. When an egg code is absent from the upstream table (real CIS feeds use tenths / list-style codes) the concentration branch falls back to an adapter-authored leading-digit ramp. The navigational mode has no upstream colours in 1.2.1, so it uses a provisional adapter-authored traffic-light mapping derived from total concentration; this is a placeholder preview only and is not a POLARIS/RIO navigational-risk computation. Select the mode from the CLI with s100 render <dataset> --display-mode <token>; the available modes are listed by s100 info <dataset>.

Other

  • S-411 has no information types (<imember> elements); only feature wrappers.
  • Coordinate ordering in <gml:pos> / <gml:posList> follows the S-100 Part 10b convention of lat lon for EPSG:4326.
  • The S-411 Portrayal Catalogue ships several top-level XSLT entry points (mainRule, plus per-ice-class rules such as SeaiceClass1ARule). Only mainRule is exposed as an active portrayal rule by default; class-specific rules are still loadable by name via GetCompiledRule.

Validation rules

EncDotNet.S100.Datasets.S411.Validation.S411SeaIceRules exposes a pilot rule pack (8 rules) for an S411SeaIceInventory, mirroring the S-421 rule pack (PR #100). Rule identifiers follow S411-R-{clause}:

Rule Severity Summary
S411-R-3.1 Error Feature coordinates must lie within WGS-84 lat/lon ranges (S-100 Part 10b §6.2).
S411-R-3.2 Error Surface features must have a closed ring with ≥ 4 coordinates.
S411-R-3.3 Error Curve features must have ≥ 2 vertices.
S411-R-4.1 Warning Egg-code totalConcentration must be one of the S-411 Annex A enumerated WMO codes.
S411-R-4.2 Error iceAverageThickness must be ≥ 0 when present.
S411-R-4.3 Error Egg-code snowDepth must be ≥ 0 when present.
S411-R-4.4 Warning icebergSize must be one of the S-411 Annex A enumerated codes (1–9, 99).
S411-R-5.1 Error Feature identifiers must be unique across the dataset.

Rules bind to the typed projection (S411SeaIceInventory, S411IceFeature subclasses) and are therefore agnostic to the two real-world GML shapes (JCOMM/Canadian Ice Service operational shape and IHO 1.2.1 sample shape). Use S411SeaIceRules.Validate(inventory) for a one-shot run against the default rule set, or compose a custom set via ValidationRuleSet<S411SeaIceInventory>.

License

The bundled S-411 specification assets in EncDotNet.S100.Specifications are © JCOMM/IHO and used in accordance with their open-publication terms; see https://github.com/iho-ohi/S-411-Product-Specification.

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