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EncDotNet.S100.Datasets.S104

Reader and coverage pipeline for S-104 Water Level Information for Surface Navigation datasets.

Overview

This library reads S-104 datasets from HDF5 files and provides gridded and positioned-station water-level time series for the portrayal pipeline. Key types include:

  • S104Dataset — root model containing horizontal CRS, vertical datum, data coding format, and time-step coverages.
  • S104DatasetReader — reads regular-grid DCF2 plus existing time-major DCF1 and station-major DCF8 datasets. DCF1 uses each Group_NNN/timePoint as the authoritative timestamp, including non-uniform axes, and transposes time-major values into the shared station-series model. The reader targets the Edition 2.0.0 HDF5 layout while retaining compatibility with older declared editions; schema failures raise S100DatasetSchemaException. The waterLevelTrend compound member accepts the signed/unsigned integer widths encountered in production, including IC-ENC's Int16 representation.
  • S104CoverageSource — ICoverageSource adapter for the coverage pipeline.
  • S104PortrayalCatalogue — viewer-parity heatmap catalogue with hand-coded Day / Dusk / Night band tables (see Portrayal below).
  • WaterLevelCoverage, WaterLevelValue — water level data models. WaterLevelCoverage.GroupPath carries the HDF5 instance path (e.g. /WaterLevel/WaterLevel.01) and is used by the validation rule pack as the per-coverage RelatedFeatureId.
  • S104TimeSeriesSampler — samples a regular-grid (dcf=2) dataset at an arbitrary geographic point across its time steps, returning an S104TimeSeries (nearest cell + a per-step S104TimeSeriesPoint list of height/trend, ordered by time and optionally windowed to a from/to range). This is the shared kernel for depth-over-time visualisations and tide reconciliation; the MCP sample_coverage windowed path delegates its nearest-cell and containment math to it. Nearest-cell selection operates in the coverage's geographic space (EPSG:4326 per S-104 Ed 2.0.0) without reprojection; NoData cells (FillValue, -9999f) report a null height.

Portrayal

S-104 Edition 2.0.0 does not define an official portrayal catalogue — the spec treats water-level data as input to ECDIS depth adjustment rather than a visual layer. S104PortrayalCatalogue therefore ships hand-coded Day / Dusk / Night band tables synthesised for viewer parity with the other coverage products (S-102, S-111):

Palette Band styling NoData fill
Day ColorBrewer-style diverging blue (below datum) → green (above datum), preserved byte-for-byte transparent (#00000000)
Dusk Day with saturation × 0.70 and lightness × 0.85 dim cool grey (#4A4A4AFF)
Night ECDIS night-mode dark navy / olive, all luminance < 0.2 darker dim grey (#1A1A1AFF)

SwitchPalette(PaletteType) actually swaps the active band table (the pre-PR-H implementation was a no-op). ResolveColorScheme populates CoverageColorScheme.NoDataColor so the renderer paints S-104 fill cells (S104CoverageSource.FillValue, -9999f) with the active palette's no-data colour rather than leaving them transparent.

If IHO publishes an official S-104 portrayal catalogue, the bundled content/S104/pc/ directory (today .gitkeep-only by design) will be the landing point and this catalogue will be re-wired against it.

Visibility and water-area clipping (issue #483)

Because the heatmap is non-normative, the gridded surface (data coding format 2) loads hidden by default in the viewer — the user can reveal it from the layer controls. Discrete positioned-station glyphs (data coding formats 1 and 8) remain visible by default; they are point features and are unaffected. S104DatasetProcessor.IsGriddedSurface distinguishes the two so the loader only defaults the surface hidden.

When the surface is shown alongside an S-101 ENC, the S-98 interoperability rule R-101-104-B (S98DefaultRules.R_101_104_B_ClipSurfaceToWater) attaches the ENC's LandArea geometry to the surface sub-layer (GridCoverageSubLayer.LandAreaMask). The coverage renderers (MapsuiCoverageRenderer and the headless CoverageHeadlessRenderer) then clip the rasterised surface to water at output-pixel resolution: CoverageLandClip.BuildLandPath projects the land polygons (honouring interior water rings via even–odd fill) into the destination pixel space and the surface is drawn under an antialiased SKClipOperation.Difference clip. Pixel-accurate clipping is essential because real S-104 grids are often very coarse (e.g. the Rotterdam sample is only 5×6 cells ≈ 1 km each); an earlier per-cell mask could only toggle whole grid cells and so straddled piers and basins. The surface is thus layered like S-102 bathymetry — beneath ENC line work and clipped to water — so it never bleeds over land.

Validation

A bundled rule pack (EncDotNet.S100.Datasets.S104.Validation.S104DatasetRules.Default) evaluates a typed S104Dataset against the S-104 Edition 2.0.0 checklist and emits a ValidationReport of findings. The pack is invoked automatically by S104DatasetProcessor.Validate() and is also runnable directly:

var report = S104DatasetRules.Default.Run(dataset);
foreach (var finding in report.Findings)
    Console.WriteLine($"{finding.RuleId} {finding.Severity}: {finding.Message}");
Rule id Severity Checks
S104-R-1.1 Error Each coverage's Values.Length equals NumPointsLatitudinal × NumPointsLongitudinal.
S104-R-1.2 Error DataCodingFormat is in the supported gridded set {2, 3}.
S104-R-2.1 Warning Coverages are strictly increasing by TimePoint (one finding at first violation; cascade suppression).
S104-R-2.2 Warning Successive TimePoint deltas vary by no more than ±10% of the median delta (skipped when Coverages.Count < 3).
S104-R-3.1 Warning MethodWaterLevelProduct is set when Coverages.Count > 1.
S104-R-4.1 Warning Non-NODATA water-level values lie in [-15, 15] m (one finding per offending coverage; -9999f/NaN/±Infinity skipped).
S104-R-4.2 Error Each coverage's origin and origin + (numPoints - 1) × spacing extent are valid in HorizontalCRS (WGS-84 ranges without antimeridian wrap when geographic; UTM bounds, reprojecting to WGS 84, when projected).
S104-PROJ-SCHEMA Error Defensive surrogate: emitted when the underlying HDF5 dataset fails schema-level parsing inside Validate().
S104-STATION-SHAPE Error Station timestamps, heights, trends, and declared sample count disagree.
S104-STATION-TIME Error Explicit station timestamps are not strictly increasing.
S104-STATION-TREND Error A station contains a trend code outside 0–3.

R-2.1 and R-2.2 are the time-axis rule patterns; they are the template the S-111 (V-3) rule pack reuses against SurfaceCurrentCoverage.

Installation

dotnet add package EncDotNet.S100.Datasets.S104
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