Japanese map symbol for a lava field

An irregular hatched area of solidified flow.

Also known as: Yoganryu mark, Lava flow mark

Maps & navigationStandard profile

Meanings

Denotes a solidified lava flow on a Japanese topographic map.

Officially standardisedVerified fact
Marks a solidified lava flow on a GSI topographic sheet.
Contexts: Maps
Officially standardisedVerified fact
Follows the outline of the flow rather than a survey boundary, so the symbol's shape is itself a record of how the lava moved.
Contexts: Maps

An irregular area filled with short broken strokes running in no consistent direction, its outline following the flow.

IdentityModerate confidence: Moderate confidence because the identity is documented in encyclopedic references, but only a single source has been found so far.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useModerate confidence: Moderate confidence because the current use is documented in encyclopedic references, but only a single source has been found so far.
Visual matchModerate confidence: Moderate confidence because the visual match is documented in encyclopedic references, but only a single source has been found so far.

Map symbols used on Japanese topographic maps
Geospatial Information Authority of Japan (GSI) · retrieved 2026-08-23
Japan's national mapping agency's own published legend. Cited for the form and meaning of a symbol on Japanese topographic maps; the historical origin of individual symbols is cited separately where claimed.

Last reviewed 2026-08-26

Meanings

Denotes a solidified lava flow on a Japanese topographic map.

Officially standardisedVerified fact

Marks a solidified lava flow on a GSI topographic sheet.

Contexts: Maps

Officially standardisedVerified fact

Follows the outline of the flow rather than a survey boundary, so the symbol's shape is itself a record of how the lava moved.

Contexts: Maps

Confidence

IdentityModerate confidence: Moderate confidence because the identity is documented in encyclopedic references, but only a single source has been found so far.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useModerate confidence: Moderate confidence because the current use is documented in encyclopedic references, but only a single source has been found so far.
Visual matchModerate confidence: Moderate confidence because the visual match is documented in encyclopedic references, but only a single source has been found so far.

Sources

Map symbols used on Japanese topographic maps
Geospatial Information Authority of Japan (GSI) · retrieved 2026-08-23
Japan's national mapping agency's own published legend. Cited for the form and meaning of a symbol on Japanese topographic maps; the historical origin of individual symbols is cited separately where claimed.

Last reviewed 2026-08-26