Chart Symbols and Abbreviations
Charts use hundreds of standardised symbols defined in INT 1 (also known as Chart 5011 in the UK). Key categories include: depth contours and soundings, rocks and wrecks, buoys and beacons, lights, anchorages, traffic separation schemes, and land features.
Blue tint indicates shallow water (drying or very shallow). White or no tint is deeper water. Green tint shows land areas that may dry. A depth sounding of 3.2 means 3.2 metres below Chart Datum. A drying height of 1.5 (underlined) means 1.5 metres above Chart Datum.
Key Points
- INT 1 (Chart 5011) — reference for all chart symbols
- Blue = shallow water, White = deeper, Green = drying land
- Soundings = depth below Chart Datum
- Underlined values = drying heights above Chart Datum
- Asterisk with purple 'flare' = light