EncDotNet.S100.Datasets.S128 0.25.1

EncDotNet.S100.Datasets.S128

EncDotNet.S100.Datasets.S128 reads IHO S-128 Catalogue of Nautical Products datasets: GML files (S-100 Part 10b) in which one agency lists the nautical products it produces and their coverage. It parses a dataset, offers queries over its product entries, projects it into a typed catalogue with resolved supersession links, validates it, and portrays the coverages. Reference it when you need to query an S-128 catalogue or validate it. To open and render any product, including S-128, use the EncDotNet.S100 package, which includes this one.

Install

dotnet add package EncDotNet.S100.Datasets.S128

Read a dataset

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

using EncDotNet.S100.Datasets.S128;
using EncDotNet.S100.Datasets.S128.DataModel;

var dataset = S128Dataset.Open("path/to/catalogue.gml");
var catalogue = S128ProductCatalogue.From(dataset, out var diagnostics);

foreach (var product in catalogue.Products)
{
    Console.WriteLine($"{product.FeatureType} {product.Id} " +
        $"(edition {product.EditionNumber}, spec {product.ProductSpecificationName})");

    foreach (var superseded in product.Supersedes)
        Console.WriteLine($"  supersedes {superseded.Id}");

    foreach (var successor in product.SupersededBy)
        Console.WriteLine($"  superseded by {successor.Id}");
}

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

Main types

What an S-128 dataset contains

Each feature describes one product and its coverage:

The upstream sample also has metadata records that the feature catalogue models as information types but that are encoded as features inside the inline <S128:members> container: DistributorInformation, ProducerInformation, ContactDetails and CatalogueSectionHeader.

Typed data model

S128ProductCatalogue, in the EncDotNet.S100.Datasets.S128.DataModel namespace, projects S128Dataset into a typed catalogue:

• Products lists every product through the S128CatalogueEntry base class. Each entry is an S128ElectronicProduct, S128PhysicalProduct or S128Service.
• Producers, Distributors, Contacts and SectionHeaders hold the metadata records.
• Supersession is resolved. Every theReference xlink with ProductMapping/categoryOfProductMapping=1 ("Higher Priority Alternative", S-128 §12) is resolved during projection. Each entry's Supersedes lists the products it supersedes, and SupersededBy lists the products that supersede it. Chains and cycles are allowed.
• References with other categoryOfProductMapping values are in RelatedProducts, with the category text kept as encoded.
• Unresolved xlinks and values that don't parse become ProjectionDiagnostic entries. From throws only when the dataset has no features and no information types.

Product status

S-128 2.0.0 has no single status attribute on a product. S128ProductEntry.Status derives one:

1. If serviceStatus is present: 1 is Planned, 2 is InForce, 3 is Withdrawn.
2. Otherwise, if distributionStatus is present: 1 is InForce, 2 is Withdrawn.
3. Otherwise, the status is InForce.

Supersession comes from the typed catalogue's Supersedes and SupersededBy, not from Status.

Validate

S128CatalogueRules, in the EncDotNet.S100.Datasets.S128.Validation namespace, is the default rule set for S128ProductCatalogue. Rule IDs have the form S128-R-{clause} and trace to S-128 Edition 2.0.0 (§12, Feature Catalogue), or to S-100 Part 10b §6 for geometry. The EncDotNet.S100 package's dataset.Validate() runs the same rule set.

using EncDotNet.S100.Datasets.S128;
using EncDotNet.S100.Datasets.S128.DataModel;
using EncDotNet.S100.Datasets.S128.Validation;

await using var stream = File.OpenRead("path/to/catalogue.gml");
var dataset = S128Dataset.Open(stream);
var catalogue = S128ProductCatalogue.From(dataset, out _);
var report = S128CatalogueRules.Validate(catalogue);

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

The rules check one catalogue at a time. Checking entries against the datasets you've actually loaded isn't included.

Portrayal

The bundled portrayal catalogue is the upstream IHO one, unchanged. Its main.xsl includes per-feature templates (ElectronicProduct.xsl, PhysicalProduct.xsl, S100Service.xsl, DistributorInformation.xsl), plus simpleLineStyle.xsl, textStyle.xsl and a Default.xsl fallback. This library adds no styling of its own; for example, entries aren't styled by status.

Outline-only coverages

The upstream rules fill each product's coverage with CHYLW, CHGRN or CHMGD at transparency 0.30 (70% opaque) on display plane OVERRADAR, and the S-98 layer stack puts S-128 on OtherChartOverlays, above the ENC's line work. Nested products, such as a harbour cell inside an approach cell, add up to about 91% opaque and hide the chart, contrary to S-98 Main §9.2.1.

Upstream reached the same view: issue #51 recommends outlines only, and the Lua port of the catalogue (pull request #56) comments the fills out. S128PortrayalCatalogue does the same with an adapter, Adapter/outlineOnly.xsl. The adapter imports the upstream main.xsl with xsl:import. For ElectronicProduct, PhysicalProduct and S100Service surfaces, it keeps everything the upstream rule emits except its areaInstruction, so coverages draw as the upstream dashed outlines.

S128CoverageOverlayTests checks that the adapter's output equals the upstream output without the fills, and that the upstream rule still emits them. When a catalogue update drops the fills, that test fails and the adapter can be removed. Moving to the upstream Lua catalogue is tracked in issue #763.

Encoding notes

Coordinates in <gml:pos> and <gml:posList> are latitude then longitude for EPSG:4326 (S-100 Part 10b §6.2).

The reader handles these producer variations, most of which it shares with the other GML products:

1. s100gml namespaces. It accepts http://www.iho.int/s100gml/5.0 (the namespace for 2.0.0), http://www.iho.int/s100gml/1.0, and the older profile namespace http://www.iho.int/S100/profile/s100gml/1.0.
2. <member> and <members> containers. It accepts both the wrapper and the inline form. The upstream 2.0.0 sample uses inline <S128:members>.
3. Commas in gml:posList and gml:pos. It accepts lon,lat lon,lat pairs written in the gml:coordinates style.
4. Longitude-first coordinates. When the dataset has a <gml:Envelope>, and the parsed coordinates clearly fall outside it as parsed but inside it when swapped, the reader swaps the axes for the whole dataset. Without an envelope it doesn't check; the upstream 2.0.0 sample has none.
5. gml:gmlId identifiers. Some S-128 GML 1.0 catalogue datasets from IC-ENC and Denmark identify features with a non-standard gml:gmlId attribute instead of gml:id. The reader accepts either. Without this, the feature identifier is empty and the feature doesn't render.
6. Polygons without an exterior. Some GML 1.0 datasets write <gml:Polygon><gml:posList>... directly, without the <gml:exterior>/<gml:LinearRing> wrapper. The shared GmlCoordinateParser reads a posList or pos sequence directly under the surface as the exterior ring.
7. One ordinate per <gml:pos>. Some GML 1.0 datasets split each coordinate across consecutive single-value <gml:pos> elements (<gml:pos>41.68</gml:pos><gml:pos>21.61</gml:pos>...). The shared GmlCoordinateParser detects this and pairs the values as latitude and longitude.

Items 5 to 7 recover geometry from S-128 GML 1.0 catalogues, which otherwise render blank. Two GML 1.0 gaps remain, tracked in issue #247: full portrayal of the GML 1.0 feature classes (ElectronicChart, PaperChart and others), and a reliable axis order for longitude-first datasets that have no <gml:Envelope>.

Limitations

• Entries aren't styled by status (in force, superseded, withdrawn, planned). The typed catalogue resolves supersession, but the portrayal doesn't use it.
• Datasets that onlineResource/linkage URLs point to aren't downloaded.
• Writing S-128 datasets isn't supported.
• Labels aren't resolved by language.
• The viewer has no catalogue browser panel for S-128. Datasets load through the standard pipeline and draw as coverage outlines.

Bundled specification

The feature and portrayal catalogues are in src/EncDotNet.S100.Specifications/content/S128/ and load through Specification.OpenFeatureCatalogueAsync() and Specification.CreatePortrayalCatalogueSource().

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.