S-57 / ISO 8211 Glossary
Key abbreviations and terminology used throughout the EncDotNet codebase, drawn from the IHO S-57 and ISO/IEC 8211 standards.
File & Record Structure
| Term | Meaning |
|---|---|
| DDR | Data Descriptive Record — the ISO 8211 schema record at the start of each file |
| CATALOG.031 | The S-57 exchange set catalog file listing all chart files |
| CATD | Catalogue Directory record within CATALOG.031 |
Data Set Fields
| Term | Meaning |
|---|---|
| DSID | Data Set Identification field (dataset metadata: name, edition, agency) |
| DSSI | Data Set Structure Information |
| DSPM | Data Set Parameters field (coordinate systems, scales, multiplication factors) |
| COMF | Coordinate Multiplication Factor — divide raw integer coordinates by this to get decimal degrees |
| SOMF | Sounding Multiplication Factor — divide raw integer depths by this |
| CSCL | Compilation Scale (e.g., 22000 for a 1:22,000 chart) |
Feature Records
| Term | Meaning |
|---|---|
| FRID | Feature Record Identifier (contains PRIM, GRUP, OBJL) |
| FOID | Feature Object Identifier (contains FIDN, FIDS) |
| OBJL | Object Label/Code (the S57ObjectCode enum value, e.g., DEPARE=42, SOUNDG=129) |
| PRIM | Geometric Primitive (Point=1, Line=2, Area=3, None=255) |
| ATTF/NATF | Feature Record Attribute Field / National Attribute Field |
| ATTL/ATVL | Attribute Label (numeric code) / Attribute Value (string) |
| FSPT | Feature-to-Spatial Record Pointer (links features to vector geometry) |
| FFPT | Feature-to-Feature Pointer (links related features) |
Vector/Spatial Records
| Term | Meaning |
|---|---|
| VRID | Vector Record Identifier |
| RCNM | Record Name Code (110=Isolated Node, 120=Connected Node, 130=Edge, 140=Face) |
| RCID | Record Identification Number |
| SG2D | 2-D Coordinate field (lat/lon as integers) |
| SG3D | 3-D Coordinate (Sounding) field (lat/lon/depth as integers) |
| VRPT | Vector Record Pointer (edge-to-node topology) |
| ORNT | Orientation (Forward=1, Reverse=2) |
| USAG | Usage Indicator (Exterior=1, Interior=2) |
| MASK | Masking Indicator (Mask=1, Show=2) |
| TOPI | Topology Indicator (Beginning=1, End=2, LeftFace=3, RightFace=4) |
Topology Model
S-57 uses chain-node topology:
- Features reference spatial records via FSPT pointers
- Area features reference Faces, which are bounded by Edges
- Edges are polylines connecting two Connected Nodes
- Isolated Nodes represent standalone points (or sounding clusters)
- Edge orientation and usage indicators determine interior vs. exterior boundaries
Coordinate Handling
- Raw coordinates in S-57 files are integers; divide by COMF (typically 10,000,000) to get lat/lon in decimal degrees
- Soundings are stored in SG3D fields; divide depth by SOMF (typically 10)