| NOS | NIMA | |
IHO/Foreign NIMA Charts |
 |
 |
Sounding in true position (NOS uses upright print on English unit charts, italics for Metric charts). |
 |
 |
Sounding out of position |
 |
|
 |
Least depth in narrow channel |
 |
 |
No bottom found at depth shown |
 |
 |
 |
Soundings unreliable or taken from a smaller-scale source (NOS uses italics for English unit charts, upright print for Metric charts). |
 |
|---|---|---|---|
 |
Drying heights above chart datum |
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|