Supplementary Suffix

Purpose

This note defines the optional alphabetical suffix used for compound features.

Source Priority

HAPI User Manual.pdf
HAPI Quick Start Guide.pdf
Point Code and Style Code.md

Definition

A Supplementary Suffix is an alphabetical character appended after a two-digit Clustering_Number to represent a compound feature at the same surveyed coordinate.

It supports the surveying practice of representing more than one physical object at a single point.

Syntax

FeatureCode + ClusteringNumber + SupplementarySuffix

Example:

KX01G

Segment	Meaning
`KX`	Kerb Bottom straight segment.
`01`	Clustering Number.
`G`	Supplementary Suffix for Grating.

Known Supplementary Suffix Rules

Feature Code	Supplementary Suffix	Compound Feature
`FX`	`G`	Gate
`KX`	`G`	Grating

Business Rules

Supplementary Suffixes are feature-specific.
The suffix must be appended after a two-digit Clustering Number.
The base feature should still be processed according to its normal geometry route.
The compound feature should be generated at the coordinate of the suffixed survey point.
A Supplementary Suffix should not be globally interpreted without checking the host Feature Code.

Example

700 KX01
701 KX01
702 KX01G
703 KC01G
704 KC01
705 KX01G
706 KX01
707 KX01

Expected behaviour:

the KX/KC records form one kerb-bottom feature string
grating symbols are placed at the points carrying suffix G
curve state is still respected for KC01G

Implementation Notes

Preferred planned functions:

ParseSupplementarySuffix
ResolveCompoundFeature
CreateCompoundFeatureSymbol

The parser should return Supplementary Suffix as a separate field rather than embedding it inside NumericSuffix.

Open Questions

Confirm the complete official Supplementary Suffix dictionary.
Confirm whether compound feature rules should live in FeatureCatalogue.json, a separate compound catalogue, or both.