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highway ontologyHighway Asset › Ground and Geotechnical System

Existing Ground Surface

highway.ground_system.existing_ground
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Definition

Natural ground line before construction, used as the earthwork datum.

Class kind
component
Abstract
no
Depth
2
Origin
reference source
Ontology
engineering-reference-book.highway v0.1.0
Aliases
OGL, Original Ground Level, NGL
Abbreviations
OGL, NGL
Last changed
7/27/2026, 2:50:06 PM

Identification

Positive labels
Existing Ground Surface, OGL, Original Ground Level, NGL
Negative labels
Visual features
irregular ground line under the formation
Min identity clues
2

Evidence

Preferred views
cross_section, longitudinal_section
Evidence types
view, detail, schedule, note, dimension, level, section_callout
Source trace required
yes

Measurements (1)

NameSymbolUnitRequired
Existing Ground LevelOGLmrequired

Relationships (1)

BOQ items (0)

None — no quantity is derived from this class directly.

Validation

Blocking if missing
no
Human review allowed
yes
  • no_evidence_no_number
  • retain_document_page_bbox_and_evidence_id
  • do_not_mix_drawing_revisions
  • do_not_average_conflicting_values
  • prefer_explicit_labels_over_shape_only
  • match_plan_profile_and_cross_section_when_applicable

Provenance

Basis
taxonomy_spec
Project values included
no
mindmap_module_spec_taxonomy_highway
no page list

Children (0)

None — this is a leaf class and can be deleted.