On hydrographic and coastal maps, the heaviest (boldest) shoreline line is conventionally used to demarcate which feature?

Introduction / Context:
Map line weights communicate hierarchy and importance. In coastal mapping, distinguishing between high- and low-water lines helps mariners and planners understand tidal inundation limits and safe clearances.

Given Data / Assumptions:

• Standard cartographic conventions are used.
• Both high-water and low-water lines may be shown, but with different emphasis.

Concept / Approach:
The high-water line often receives a heavier (bolder) representation to show the land–sea boundary at maximum regular tidal reach, which is relevant for property limits, coastal regulation lines, and planning. Low-water lines and marsh/swamp limits are shown with lighter or patterned symbols; current directions are indicated by arrows, not bold shorelines.

Step-by-Step Solution:
Identify which shoreline is emphasized: in many charting conventions, the high-water line is the bold coast outline.Other features (low-water line, swamp limits, currents) use different symbols or weights.Hence, the heaviest line marks the high-water line.

Verification / Alternative check:
Review of coastal map legends confirms heavier coast outlines correspond to high-water lines.

Why Other Options Are Wrong:

• Low-water lines are typically lighter or dashed.
• Swamp limits use distinct hachures/patterns.
• Current direction is not represented by shorelines at all.

Common Pitfalls:

• Assuming low-water is bold because nautical depths use low-water datum—line weight is a cartographic choice, not a datum indicator.

Final Answer:
the high water line