EncDotNet.S100.Datasets.S104 0.25.1

EncDotNet.S100.Datasets.S104

This package reads S-104 Water Level Information for Surface Navigation datasets from HDF5 files: water-level grids per time step, and time series at fixed stations. It also draws them as a colour-banded surface and validates them against the S-104 Edition 2.0.0 checklist. Reference it when you need the water levels directly, for example to sample a tide curve at a position. To open and render a dataset without wiring catalogues yourself, use the EncDotNet.S100 package instead.

Install

dotnet add package EncDotNet.S100.Datasets.S104
dotnet add package EncDotNet.S100.Hdf5.PureHdf

EncDotNet.S100.Hdf5.PureHdf provides the HDF5 reader the example uses.

Read a dataset

A file holds either a regular grid per time step or a series of values per station. ReadAny returns whichever the file contains:

using EncDotNet.S100.Datasets.S104;
using EncDotNet.S100.Hdf5.PureHdf;

using var file = PureHdfFile.Open("path/to/dataset.h5");

switch (S104DatasetReader.ReadAny(file))
{
    case S104DatasetData.GriddedCoverage gridded:
        foreach (WaterLevelCoverage step in gridded.Dataset.Coverages.Take(3))
            Console.WriteLine($"{step.TimePoint:u}: {step.Values.Length} cells");
        break;

    case S104DatasetData.StationSeries stations:
        foreach (WaterLevelStation station in stations.Dataset.Stations)
            Console.WriteLine($"{station.Identifier}: {station.NumberOfTimes} samples");
        break;
}

Each WaterLevelValue has a Height in metres relative to the dataset's vertical datum and a Trend: 1 (decreasing), 2 (increasing), 3 (steady) or 0 (unknown). Grid cells without data hold the fill value -9999. For more, see Reading product data.

Main types

• S104Dataset: a gridded dataset, with its horizontal CRS, vertical datum, data coding format and one coverage per time step.
• S104DatasetReader: reads data coding formats 2 (regular grid), 1 (time-major station series) and 8 (station-major station series).
  • For format 1, each Group_NNN/timePoint is the timestamp, including on uneven time axes. The time-major values are transposed into the same per-station model as format 8.
  • The reader targets the Edition 2.0.0 HDF5 layout and still reads datasets that declare older editions. Schema errors throw S100DatasetSchemaException.
  • The waterLevelTrend compound member accepts the signed and unsigned integer widths found in production data, including IC-ENC's Int16.
• WaterLevelCoverage and WaterLevelValue: a grid at one time step and its values. WaterLevelCoverage.GroupPath is the HDF5 path of the coverage, such as /WaterLevel/WaterLevel.01. Validation findings use it as RelatedFeatureId.
• S104StationSeriesDataset and WaterLevelStation: a station series and one station's heights and trends.
• S104TimeSeriesSampler: samples a regular-grid (format 2) dataset at a geographic position across its time steps. It returns an S104TimeSeries: the nearest cell and an S104TimeSeriesPoint per step with height and trend, in time order and optionally limited to a from/to range. It finds the nearest cell in the coverage's geographic coordinates (EPSG:4326 in S-104 Ed 2.0.0) without reprojecting. Cells with the fill value report a null height. The MCP server's sample_coverage tool uses it for time windows.
• S104CoverageSource: the ICoverageSource for the coverage pipeline.
• S104PortrayalCatalogue: the colour bands for the water-level surface. See Portrayal.

The S104DatasetProcessor that renders, samples and validates a dataset is in EncDotNet.S100.Datasets.Pipelines.

Portrayal

S-104 Edition 2.0.0 has no portrayal catalogue. The specification treats water levels as input for ECDIS depth adjustment rather than as a layer to draw. So that S-104 can be shown like the other coverage products (S-102, S-111), S104PortrayalCatalogue defines its own Day, Dusk and Night colour bands:

SwitchPaletteAsync(PaletteType) switches the active band table. ResolveColorScheme sets CoverageColorScheme.NoDataColor, so the renderer paints fill-value cells (S104CoverageSource.FillValue, -9999) in the active palette's no-data colour.

The content/S104/pc/ folder in EncDotNet.S100.Specifications is empty. If the IHO publishes an S-104 portrayal catalogue, it goes there and this catalogue will use it.

Visibility and clipping to water

The colour bands aren't defined by the specification, so SoundCharts loads the gridded surface (data coding format 2) hidden. You can show it from the layer controls. Station glyphs (formats 1 and 8) are point features and are shown by default. S104DatasetProcessor.IsGriddedSurface tells the two apart.

When the surface is shown with 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 surface to water at output-pixel resolution. CoverageLandClip.BuildLandPath projects the land polygons into pixel space, keeping interior water rings with even-odd fill, and the surface is drawn under an antialiased SKClipOperation.Difference clip. Clipping per pixel rather than per grid cell matters because S-104 grids are often coarse: the Rotterdam sample is 5×6 cells of about 1 km each. The surface is layered like S-102 bathymetry, under the ENC's line work and clipped to water, so it doesn't cover land.

Validation

The bundled rule pack, EncDotNet.S100.Datasets.S104.Validation.S104DatasetRules.Default, checks an S104Dataset against the S-104 Edition 2.0.0 checklist and returns a ValidationReport. S104DatasetProcessor.Validate() runs it for you. To run it directly:

using EncDotNet.S100.Datasets.S104.Validation;

var report = S104DatasetRules.Default.Run(dataset);
foreach (var finding in report.Findings)
    Console.WriteLine($"{finding.RuleId} {finding.Severity}: {finding.Message}");

S104DatasetProcessor checks station series itself with the S104-STATION-* rules, because the rule pack works on gridded S104Datasets. The S-111 rule pack reuses the time-axis checks in S104-R-2.1 and S104-R-2.2.

For the validation API and your own rules, see Custom catalogues and validation.

See also

• Reading product data: read grids and station series for S-104 and S-111.
• S-98 interoperability: how S-104 is layered with other products.