🔍 Key Concepts
• Chart symbols for positions such as fix, dead reckoning (DR), running fix, and estimated position (EP)
• Difference between a precise position and a predicted or approximated position
• Standard plotting symbols used in traditional coastal navigation
💭 Think About
• Think about which of these positions is usually completely enclosed (for example, by a circle) versus one that is partially enclosed, like with a semi-circle.
• Ask yourself: which type of position depends on measured lines of position (LOPs) and which depends mainly on course and speed through the water?
• Consider which type of position symbol is used when you are least certain of your exact location and are allowing for possible error.
✅ Before You Answer
• Verify which symbol on a standard paper chart uses a full circle versus a semi-circle.
• Check which position type (fix, DR, running fix, or EP) is associated with no visual or electronic observations, only course, speed, and time.
• Confirm from a navigation textbook or plotting guide which position symbol is used when allowing for current, wind, and other unknowns.