s101-enc

name: s101-enc description: | Expert knowledge of IHO S-101 Electronic Navigational Chart Product Specification. Covers ISO 8211 record encoding (S-100 Part 10a), S-101 feature/spatial/information records, the Lua-based portrayal pipeline (S-100 Part 9A) including drawing instructions, symbol references, line/area styles, and the data provider contract used by rule scripts. USE FOR: S-101 datasets, ENC files, ISO 8211 parsing, S101DocumentReader, S101Dataset, S101VectorSource, S101LuaPortrayal, S101LuaDataProvider, DrawingInstructionParser, S101PortrayalCatalogue, drawing instructions, Lua portrayal rules, vector pipeline changes affecting S-101, adding S-101 features. DO NOT USE FOR: S-124 GML-encoded features (use s124-nav-warnings), HDF5 coverage products S-102/S-104/S-111 (use their respective skills), generic S-100 framework questions (use s100-framework).

S-101 ENC expert

When engaged

• Tasks touching src/EncDotNet.S100.Datasets.S101/** or tools/TestS101Lua/**
• Changes to the vector pipeline (VectorPipeline, IVectorSource, IVectorPortrayalCatalogue) that affect S-101
• ISO 8211 reader integration (EncDotNet.Iso8211 package usage)
• Lua portrayal authoring, debugging, sandboxing concerns
• Drawing instruction parsing or rendering of S-101 output

Spec anchors

• Canonical: S-101 Edition 1.x product specification
• S-100 Part 9 / 9A: Portrayal catalogue + Lua rules engine
• S-100 Part 10a: ISO 8211 encoding
• S-101 Annex A: Feature Catalogue
• S-101 Annex B: Portrayal Catalogue

Review checklist

1. ISO 8211 record reads go through EncDotNet.Iso8211; do not re-implement field/subfield parsing.
2. Feature/Spatial/Information records map to the model defined in S101Document.cs; preserve invariants when adding fields.
3. Lua execution stays inside MoonSharpLuaEngine (sandboxed Lua 5.2). Do not expose host file IO or reflection to scripts.
4. S101LuaDataProvider is the only contract the rules see — every addition is a spec-defined function from S-100 Part 9A; cite the section in XML docs.
5. Drawing instructions parsed by DrawingInstructionParser must round-trip through DrawingInstruction records used by the renderers (Skia / Mapsui).
6. Portrayal catalogue assets are loaded via S101PortrayalCatalogue from EncDotNet.S100.Specifications (not hard-coded in the dataset library).
7. Tests live in tests/EncDotNet.S100.Pipelines.Tests (or a dedicated S101 test project). Use SkippableFact when a real ENC is required.

Known pitfalls in this repo

• ISO 8211 string fields can be ISO/IEC 8859-1, UTF-8, or UCS-2; honor the DSSI/DSPM character set declaration rather than assuming UTF-8.
• Lua 5.2 (MoonSharp) — not 5.1 or 5.4. Avoid goto/bit32 quirks.
• Drawing instruction priorities and the display-priority ordering are spec-defined; do not reorder in the renderer.
• Coordinate values in S-101 are in COMF/SOMF-scaled integers; convert to decimal degrees at the source boundary.